Replimune Group, Inc. (REPL)

Item 7.    Management’s discussion and analysis of financial condition and results of operations

You should read the following discussion and analysis of our financial condition and results of operations in conjunction with our consolidated financial statements and related notes and other financial information included elsewhere in this Annual Report on Form 10-K. In addition to historical information, some of the statements contained in this discussion and analysis or set forth elsewhere in this Annual Report on Form 10-K, including information with respect to our plans and strategy for our business, constitute forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act. We have based these forward-looking statements on our current expectations and projections about future events. The following information and any forward-looking statements should be considered in light of factors discussed elsewhere in this Annual Report on Form 10-K, particularly including those risks identified in Part I, Item 1A “Risk factors” and our other filings with the SEC.

We caution you that forward-looking statements are not guarantees of future performance and that our actual results of operations, financial condition and liquidity, and the development of the industry in which we operate may differ materially from the forward-looking statements contained in this Annual Report on Form 10-K. Statements made herein are as of the date of the filing of this Annual Report on Form 10-K with the SEC and should not be relied upon as of any subsequent date. Even if our results of operations, financial condition and liquidity, and the development of the industry in which we operate are consistent with the forward-looking statements contained in this Annual Report on Form 10-K, they may not be predictive of results or developments in future periods. We disclaim any obligation, except as specifically required by law and the rules of the SEC, to publicly update or revise any such statements to reflect any change in our expectations or in events, conditions or circumstances on which any such statements may be based or that may affect the likelihood that actual results will differ from those set forth in the forward-looking statements.

61

TABLE OF CONTENTS

Overview

We are a clinical-stage biotechnology company committed to applying our leading expertise in the field of oncolytic immunotherapy to transform the lives of cancer patients through our novel oncolytic immunotherapies. Our proprietary oncolytic immunotherapy product candidates are designed and intended to maximally activate the immune system against cancer.

Oncolytic immunotherapy is an emerging drug class, which we intend to establish as the second cornerstone of immune-based cancer treatments, alongside checkpoint blockade. Oncolytic immunotherapy exploits the ability of certain viruses to selectively replicate in and directly kill tumors, as well as induce a potent, patient-specific, anti-tumor immune response. Our product candidates incorporate multiple mechanisms into a practical “off-the-shelf” approach that is intended to maximize the immune response against a patient’s cancer and to offer significant advantages over other approaches of inducing anti-tumor immunity, including personalized vaccine approaches. We believe that the bundling of multiple approaches for the treatment of cancer into single therapies will increase clinical efficacy and simplify the development path of our product candidates, while also improving patient outcome.

Financial

Since our inception, we have devoted substantially all of our resources to developing our proprietary RPx platform, building our intellectual property portfolio, conducting research and development of our product candidates, business planning, raising capital and providing selling, general and administrative support for our operations. To date, we have incurred significant operating losses and we have financed our operations primarily with proceeds from the sale of equity securities and to a lesser extent the proceeds from the issuance of debt securities. Our ability to generate product revenue sufficient to achieve profitability will depend on the successful development and eventual commercialization of one or more of our product candidates. We do not have any products approved for sale and have not generated any revenue from product sales.

Since our initial public offering, or IPO, on July 20, 2018, we have raised an aggregate of approximately $1,101.8 million in net proceeds to fund our operations, of which $101.2 million was from our IPO, $862.0 million was from five separate follow-on offerings, or the Public Offerings, that we closed in November 2019, June 2020, October 2020, December 2022, and November 2024, respectively, $96.7 million was from our private placement transaction in June 2024, and $41.9 million was from at-the-market offerings.

Our net losses were $247.3 million and $215.8 million for the years ended March 31, 2025 and 2024, respectively. As of March 31, 2025, we had an accumulated deficit of $948.6 million. These losses have resulted primarily from costs incurred in connection with research and development activities and selling, general and administrative costs associated with our operations. We expect to continue to incur significant expenses and increasing operating losses for at least the next several years.

We anticipate that our expenses and capital requirements will fluctuate from period to period depending upon the Company's development programs and priorities. We expect to continue to incur costs in connection with our ongoing development activities, including further advancement of any preclinical activities and clinical trials of our product candidates across our platform, and if and as we:

•conduct our current and future clinical trials;

•further preclinical development of our platform;

•operate our in-house manufacturing facility;

•seek to identify and develop additional product candidates;

•seek marketing approvals for any of our product candidates that successfully complete clinical trials, if any;

•establish a sales, marketing and distribution infrastructure to commercialize any products for which we may obtain marketing approval;

•until our manufacturing facility is fully validated, continued limited manufacturing by third parties for clinical development;

•maintain, expand and protect our intellectual property portfolio;

•hire and retain additional clinical, quality control, scientific and selling, general and administration personnel;

•acquire or in-license other drugs, technologies or intellectual property rights; and

62

TABLE OF CONTENTS

•add operational, financial and management information systems and personnel, including personnel to support our research and development programs, any future commercialization efforts and operations as a public company.

Because of the numerous risks and uncertainties associated with pharmaceutical product development, we are unable to accurately predict the timing or amount of increased expenses or when, or if, we will be able to achieve or maintain profitability. Even if we are able to generate product sales, we may not become profitable. If we fail to become profitable or are unable to sustain profitability on a continuing basis, then we may be unable to continue our operations at planned levels and be forced to reduce or terminate our operations.

As of March 31, 2025, we had cash and cash equivalents and short-term investments of $483.8 million. Based on our current operating plan, we believe that our existing cash and cash equivalents and short-term investments will enable us to fund our operating expenses and capital expenditure requirements through at least 12 months from the issuance of the consolidated financial statements included in this Annual Report on Form 10-K.

See “Results of Operations — Liquidity and capital resources” and “Risk factors — Risks related to our financial position and need for additional capital.”

Components of our results of operations

Revenue

To date, we have not generated any revenue from product sales as we do not have any approved products and we can not be certain we will generate any revenue from the sale of products in the future. If our development efforts for RP1 or any other product candidates that we may develop in the future are successful and result in regulatory approval, or if we enter into collaboration or license agreements with third parties, we may generate revenue in the future from a combination of product sales or payments from those collaborations or license agreements.

Operating expenses

Research and development expenses

Research and development expenses consist primarily of costs incurred for our research activities, including our discovery efforts and the development of our product candidates, and include:

•expenses incurred under agreements with third parties, including clinical research organizations, or CROs, that conduct research, preclinical activities and clinical trials on our behalf as well as contract manufacturing organizations, or CMOs that manufacture our product candidates for use in our preclinical and clinical trials;

•salaries, benefits and other related costs, including stock-based compensation expense, for personnel engaged in research and development functions;

•costs of outside consultants engaged in research and development functions, including their fees, stock-based compensation and related travel expenses;

•the costs of laboratory supplies and acquiring, developing and manufacturing preclinical study and clinical trial materials;

•costs related to compliance with regulatory requirements in connection with the development of our product candidates; and

•facility-related expenses, which include direct depreciation costs and allocated expenses for rent and maintenance of facilities and other operating costs.

We expense research and development costs as incurred. We recognize external development costs based on an evaluation of the progress to completion of specific tasks using information provided to us by our service providers. Payments for these activities are based on the terms of the individual agreements, which may differ from the pattern of costs incurred, and are reflected in our consolidated financial statements as prepaid or accrued research and development expenses.

Direct research and development costs, consisting of costs, such as fees paid to consultants, contractors, CMOs and CROs in connection with our preclinical and clinical development activities, are tracked by study. Additional costs, consisting primarily of our initial manufacturing costs, including materials, supplies, depreciation and facility costs, are allocated at a program level, based upon manufacturing runs, as the drug product can be utilized across multiple studies for any particular program. Additional costs to label, package and distribute the drug product is then directly allocated to the specific studies when

63

TABLE OF CONTENTS

incurred, as that drug product has then been assigned to a particular study. In the event our additional future or ongoing study costs become meaningful to investors, we will present those costs by study.

We do not allocate personnel costs, costs associated with our discovery efforts, laboratory supplies or other indirect costs, to specific product development programs because these costs are deployed across multiple product development programs and, as such, are not separately classified.

Research and development activities are central to our business model. Product candidates in later stages of clinical development generally have higher development costs than those in earlier stages of clinical development, primarily due to the increased size and duration of later-stage clinical trials. We expect that our research and development expenses will continue to increase for the foreseeable future as we continue enrollment and initiate additional clinical trials and continue to discover and develop additional product candidates. The successful development and commercialization of our product candidates is highly uncertain. This is due to the numerous risks and uncertainties associated with product development and commercialization, including the following:

•the scope, rate of progress, expense and results of our ongoing clinical trials, as well as future clinical trials or other product candidates and other research and development activities that we may conduct;

•the number and scope of preclinical and clinical programs we decide to pursue;

•our ability to maintain our current research and development programs and to establish new ones;

•uncertainties in clinical trial design;

•the rate of enrollment in clinical trials;

•the successful completion of clinical trials with safety, tolerability, and efficacy profiles that are satisfactory to the FDA or any comparable foreign regulatory authority;

•the receipt of regulatory approvals from applicable regulatory authorities, if any, and our ability to maintain approval of any of our product candidates;

•our success in operating our manufacturing facility, or securing manufacturing supply through relationships with third parties;

•our ability to obtain and maintain patents, trade secret protection, and regulatory exclusivity, both in the United States and internationally;

•our ability to maintain, expand and protect our rights in our intellectual property portfolio;

•the commercialization of our product candidates, if and when approved;

•the acceptance of our product candidates, if approved, by patients, the medical community, and third-party payors;

•our ability to successfully develop our product candidates for use in combination with third-party products or product candidates;

•negative developments in the field of immuno-oncology;

•competition with other products; and

•significant and changing government regulation and regulatory guidance.

A change in the outcome of any of these variables with respect to the development of a product candidate could mean a significant change in the costs and timing associated with the development of that product candidate. For example, if the FDA or another regulatory authority were to require us to conduct clinical trials beyond those that we anticipate will be required for the completion of clinical development of a product candidate, or if we experience significant trial delays due to patient enrollment or other reasons, we could be required to expend significant additional financial resources and time on the completion of clinical development. We may never succeed in obtaining regulatory approval for any of our product candidates.

Selling, general and administrative expenses

Selling, general and administrative expenses consist primarily of salaries and other related costs, including stock-based compensation, for personnel in our executive, finance, corporate, commercial, and business development and administrative functions. Selling, general and administrative expenses also include professional fees for legal, patent, accounting, auditing, tax and consulting services, pre-commercial planning, travel expenses, and facility-related expenses, which include direct depreciation costs and allocated expenses for rent and maintenance of facilities and other operating costs.

64

TABLE OF CONTENTS

We expect that our selling, general and administrative expenses will continue to increase in the future as we increase our selling, general and administrative headcount to support our continued operations and pre-launch activities to prepare for potential commercialization of our product candidates. We also expect to continue to incur increased expenses, including accounting, audit, legal, regulatory and tax-related services associated with maintaining compliance with exchange listing and SEC requirements; director and officer insurance costs; and investor and public relations costs.

Other income (expense), net

Research and development incentives

Research and development incentives consists of reimbursements of research and development expenditures. We participate, through our subsidiary in the United Kingdom, in the research and development program provided by the United Kingdom tax relief program, such that a percentage of up to 16.2% of our qualifying research and development expenditures are reimbursed by the United Kingdom government, and such incentives are reflected as other income.

Investment income

Investment income consists of income earned on our cash and cash equivalents and short-term investments.

Interest expense on finance lease liability

Interest expense on finance lease liability consists of amortization of finance charges under our financing lease.

Interest expense on debt obligations

Interest expense on debt obligations consists of the amortization of debt discount and cash paid for interest under the Hercules Loan Agreement.

Other (expense) income, net

Other (expense) income, net consists primarily of realized and unrealized foreign currency transaction gains and losses.

Income taxes

During the year ended March 31, 2025 and 2024, the Company recorded an income tax provision of $0.5 million and $0.4 million, respectively, related to U.S. current taxes primarily due to the transfer pricing arrangement between the U.S. and the U.K., as well as unfavorable adjustments related to stock compensation, resulting in U.S. taxable income partially reduced by certain tax attributes and U.S. tax partially reduced by certain credits and U.S. tax partially reduced by certain credits.

Results of operations

Comparison of the years ended March 31, 2025 and 2024

The following table summarizes our results of operations for the years ended March 31, 2025 and 2024:

65

TABLE OF CONTENTS

Research and development expenses

Research and development expenses for the year ended March 31, 2025 were $189.4 million, compared to $175.0 million for the year ended March 31, 2024. The following table summarizes our research and development expenses for the years ended March 31, 2025 and 2024:

The total increase of $14.5 million in research and development expenses was driven by an increase of $26.0 million in unallocated expenses, partially offset by a decrease of $11.5 million in our direct research and development costs. The increase in unallocated expenses includes $14.8 million in other costs and $11.2 million in personnel-related costs. The increase in other costs is driven primarily by an increase in consulting costs, medical affairs and facility costs. The increase in personnel-related costs largely reflected the hiring of additional personnel in our research and development functions, most specifically within the manufacturing departments, as we prepared and scaled operations for commercial launch.

The decrease of approximately $11.5 million in our direct research and development costs primarily relates to a decrease of $8.2 million related to RP3 as a result of the deprioritization of development efforts on this product candidate, which began in

66

TABLE OF CONTENTS

the second half of the prior fiscal year, as well as a decrease of $4.6 million in RP1 costs as a result of declining enrollment and the wind down of the CERPASS study and completion of enrollment in the IGNYTE advanced melanoma cohort. These decreases are slightly offset by an increase of approximately $1.3 million in RP2 costs as the Company began to ramp up costs for the MUM study, specifically with spending related to set up costs and Clinical Research Organization ("CRO") costs. In addition, in the prior year, the company incurred costs related to manufacturing batches for RP1, as well as significant costs related to the CERPASS trial in the areas of CROs, investigators and imaging costs in preparation of the primary data release, which did not recur in the current year.

Selling, general and administrative expenses

Selling, general and administrative expenses were $72.2 million for the year ended March 31, 2025, compared to $59.8 million for the year ended March 31, 2024. The increase of $12.4 million in sales, general and administrative costs is driven primarily by an increase of $9.3 million in sales and marketing costs related to promotional materials, market access and insights and analytics, as the Company prepares for a potential commercial launch of RP1. In addition, there is a year over year increase of $4.3 million in personnel related costs, comprised of an increase of $7.1 million in payroll and fringe benefits offset by a stock-based compensation decrease of $2.8 million. The increase in personnel related costs was driven by the continued hiring of additional personnel within our selling, general and administrative functions, specifically focusing on planning for a potential commercial launch. Personnel related costs for the year ended March 31, 2025 and 2024 included stock-based compensation expense of $16.6 million and $19.4 million, respectively.

Total other income (expense), net

Other income for the year ended March 31, 2025 was $14.8 million compared to $19.4 million for the year ended March 31, 2024. The net change of $4.6 million is primarily attributable to a decrease of $2.2 million in investment income in the current year as compared to the prior year as a result of the cash and investment balance being lower throughout the year as compared to the prior year due to normal cash burn, as well as an increase in interest expense on debt obligations in the amount of $1.3 million as a result of a higher debt balance during the current year vs. the prior year. In addition, there is a $1.0 million increase in expense due to the changes in foreign exchange rates of the Great British Pound to United States Dollar.

Income tax provision

Income tax provision for the year ended March 31, 2025 was $0.5 million compared to $0.4 million for the year ended March 31, 2024. The income tax provision for the current year is attributable to U.S. current taxes primarily due to the transfer pricing arrangement between the U.S. and the U.K., as well as unfavorable adjustments related to stock compensation, resulting in U.S. taxable income partially reduced by certain prior year available net operating losses and U.S. tax partially reduced by certain credits.

Liquidity and capital resources

Since our inception, we have not generated any revenue from product sales and have incurred significant operating losses and negative cash flows from our operations. Until we are able to generate sufficient revenue from RP1 and our other product candidates that we develop, if at all, we anticipate that we will continue to incur significant operating losses and negative cash flows from our operations.

Sources of liquidity

To date, we have financed our operations primarily with proceeds from the sale of equity securities and, to a lesser extent, proceeds from borrowing under a secured loan facility. Through March 31, 2025, we had received net proceeds of $1,101.8 million through the sale of shares of common stock and pre-funded warrants exercisable for common stock in public offerings, a private placement transaction, and at-the-market offerings, as well as our incurrence of debt under the Hercules Loan Agreement. As of March 31, 2025, we had cash and cash equivalents and short-term investments of $483.8 million.

Cash flows

The following table summarizes our cash flows for each of the periods presented:

67

TABLE OF CONTENTS

Operating activities

During the year ended March 31, 2025, net cash used in operating activities was $192.3 million, primarily resulting from our net loss of $247.3 million, which was partially offset by non-cash charges of $31.0 million, consisting primarily of stock-based compensation expense of $35.0 million and depreciation expense of $3.5 million, somewhat offset by $8.9 million related to the net amortization of premiums and discounts on short-term investments. Additionally, there was an increase in cash of $24.1 million related to changes in our operating assets and liabilities. Changes in our operating assets and liabilities for the year ended March 31, 2025 consisted primarily of a $11.7 million increase in accrued expenses and other current liabilities, a $9.9 million increase in accounts payable, and a net $2.4 million change in operating and financing right-of-use assets and lease liabilities.

During the year ended March 31, 2024, net cash used in operating activities was $185.5 million, primarily resulting from our net loss of $215.8 million, which was partially offset by non-cash charges of $24.8 million, consisting primarily of stock-based compensation expense of $34.1 million offset by $12.3 million related to the net amortization of premiums and discounts on short-term investments. Additionally, there was an increase in cash of $5.5 million related to changes in our operating assets and liabilities. Changes in our operating assets and liabilities for the year ended March 31, 2024 consisted primarily of a $9.2 million increase in accrued expenses and other current liabilities, a $2.8 million decrease in accounts payable, and a net $2.4 million change in operating and financing right-of-use assets and lease liabilities.

Investing activities

During the year ended March 31, 2025, net cash used in investing activities was $23.8 million, consisting of $403.6 million in purchases of available for sale securities and $6.7 million in purchases of property, plant and equipment, partially offset by $386.5 million in proceeds from sales and maturities of short-term investments.

During the year ended March 31, 2024, net cash provided by investing activities was $97.2 million, consisting of $592.4 million in proceeds from sales and maturities of short-term investments, partially offset by $489.5 million in purchases of available for sale securities and $5.7 million in purchases of property, plant and equipment.

Financing Activities

During the year ended March 31, 2025, net cash provided by financing activities was $252.4 million, consisting primarily of $252.7 million in proceeds from the Company's private placement transaction in June 2024 as well as the Company's November 2024 public offering.

During the year ended March 31, 2024, net cash provided by financing activities was $16.3 million, consisting primarily of $15.0 million in proceeds from the incurrence of debt under the Hercules Loan Agreement, as well as approximately $1.8 million in proceeds from the exercise of stock options.

Funding requirements

Our plan of operation is to continue implementing our business strategy, continue research and development of RP1 and our other product candidates and continue to expand our research pipeline and our internal research and development capabilities. We expect our expenses to increase substantially in connection with our ongoing activities, particularly as we advance the preclinical activities and clinical trials of our product candidates, and potential commercialization of RP1 and if and as we:

•conduct our current and future clinical trials with RP1, RP2 and RP3;

•further preclinical development of our RPx platform;

68

TABLE OF CONTENTS

•operate, qualify and maintain our in-house manufacturing facility and qualify and maintain our product candidates made therein for use in our clinical trials;

•seek to identify and develop additional product candidates;

•seek marketing approvals for any of our product candidates that successfully complete clinical trials, if any;

•establish a sales, marketing and distribution infrastructure to commercialize any products for which we may obtain marketing approval;

•until our planned manufacturing facility is fully validated, continued limited manufacturing by third parties for clinical development;

•maintain, expand and protect our intellectual property portfolio;

•acquire or in-license other drugs, technologies or third-party intellectual property; and

•add operational, financial and management information systems and personnel, including personnel to support our research and development programs, any future commercialization efforts and operations as a public company.

As of March 31, 2025, we had cash and cash equivalents and short-term investments of $483.8 million and $46.4 million in long term debt. Based on our current operating plan, we believe that our existing cash, cash equivalents and short-term investments as of March 31, 2025, will enable us to fund operations into the calendar fourth quarter of 2026 which includes scale up for the potential commercialization of RP1 in skin cancers and for working capital and general corporate purposes and excludes any potential revenue. We have based these estimates on assumptions that may prove to be wrong, and we could utilize our available capital resources sooner than we expect.

Because of the numerous risks and uncertainties associated with the development of RP1 and other product candidates and programs, and because the extent to which we may enter into collaborations with third parties for development of our product candidates is unknown, we are unable to estimate the timing and amounts of increased capital outlays and operating expenses associated with completing the research and development and potential commercialization of our product candidates. Our future capital requirements will depend on many factors, including those described in this section and above under “— Operating expenses — Research and development expenses.”

Developing novel biopharmaceutical products, including conducting preclinical studies and clinical trials, is a time-consuming, expensive and uncertain process that takes years to complete, and we may never generate the necessary data or results required to obtain marketing approval for any product candidates or generate revenue from the sale of any products for which we may obtain marketing approval. In addition, our product candidates, if approved, may not achieve commercial success. Our commercial revenues, if any, will be derived from sales of therapies that we do not expect to be commercially available for many years, if ever. Accordingly, we will need to obtain substantial additional funds to achieve our business objectives.

Adequate additional funds may not be available to us on acceptable terms, or at all. We do not currently have any committed external source of funds. To the extent that we raise additional capital through the sale of our equity or convertible debt securities, our shareholders’ interest may be diluted, and the terms of these securities may include liquidation or other preferences and anti-dilution protections that could adversely affect the rights of our common stockholder. Additional debt or preferred equity financing, if available, may involve agreements that include restrictive covenants that may limit our ability to take specific actions, such as incurring debt, adversely impact our ability to conduct our business, and may require the issuance of warrants, which could potentially dilute your ownership interest.

If we raise additional funds through collaborations, strategic alliances or licensing arrangements with third parties, we may have to relinquish valuable rights to our technology, future revenue streams, research programs, or product candidates or grant licenses on terms that may not be favorable to us. If we are unable to raise additional funds through equity or debt financings or collaborations, strategic alliances or licensing arrangements with third parties when needed, we may be required to delay, limit, reduce and/or terminate our product development programs or any future commercialization efforts or grant rights to develop and market product candidates that we would otherwise prefer to develop and market ourselves.

Contractual obligations and commitments

We have entered into arrangements that contractually obligate us to make payments that will affect our liquidity and cash flows in future periods. Our contractual obligations include those related to our operating and financing leases, long-term debt,

69

TABLE OF CONTENTS

as well as costs associated with contracts entered into in the normal course of business with CROs, CMOs and other third parties for clinical trials and preclinical research studies and testing.

Lease Commitments

As of March 31, 2025, the aggregate amount of future lease payments is approximately $49.1 million, with $4.0 million due within one year. For additional information on our leases and timing of future payments, see Note 13 Commitments and contingencies, of the "Notes to Consolidated Financial Statements" contained in Part II, Item 8 of this Annual Report on Form 10-K.

Loan Agreement

Our commitments due for our term loan under our arrangement with Hercules include principal payments of $45.0 million as of March 31, 2025. Borrowings under the term loan agreement are repayable in monthly interest-only payments through September 2026, and the agreement has a maturity date of October 2027. Our remaining commitments, based on our current draws, are due through October 2027, and include principal and interest payments of $58.3 million, and an additional fee upon maturity of the loan of $2.2 million. See Note 7, Long term debt, of the "Notes to Consolidated Financial Statements" contained in Part II, Item 8 of this Annual Report on Form 10-K for further discussion of the Hercules term loan.

Other Obligations

Manufacturing and research commitments include agreements that are enforceable and legally binding on us and that specify all significant terms, including fixed or minimum quantities to be purchased; fixed, minimum or variable price provisions; and the approximate timing of the transaction. As of March 31, 2025, the aggregate amount of non-cancelable purchase obligations related to such manufacturing commitments are approximately $0.8 million and all of this balance is due within one year.

Collaborations

BMS

In February 2018, we entered into a Clinical Trial Collaboration and Supply Agreement with Bristol-Myers Squibb Company, or BMS. Pursuant to the agreement, BMS is providing to us, at no cost, nivolumab, its anti-PD-1 therapy, for use in combination with RP1 in our ongoing Phase 1/2 clinical trial. Under the agreement, we will sponsor, fund and conduct the clinical trial in accordance with an agreed-upon protocol. BMS granted us a non-exclusive, non-transferrable, royalty-free license (with a right to sublicense) under its intellectual property to use nivolumab in the clinical trial and has agreed to supply nivolumab, at no cost to us, for use in the clinical trial. Both parties will own the study data produced in the clinical trial, other than study data related solely to nivolumab, which will belong solely to BMS, or study data related solely to RP1, which will belong solely to us. In January 2020, this agreement was expanded to cover an additional cohort of 125 patients with anti-PD-1 failed melanoma.

Unless earlier terminated, the agreement will remain in effect until (i) the completion of the clinical trial, (ii) all related clinical trial data have been delivered to both parties and (iii) the completion of any statistical analyses and bioanalyses contemplated by the clinical trial protocol or any analysis otherwise agreed upon by the parties. The agreement may be terminated by either party (x) in the event of an uncured material breach by the other party, (y) in the event the other party is insolvent or in bankruptcy proceedings or (z) for safety reasons. Upon termination, the licenses granted to us to use nivolumab in the clinical trial will terminate. The agreement contains representations, warranties, undertakings and indemnities customary for a transaction of this nature.

In April 2019, we entered into a separate agreement with BMS on terms similar to the terms set forth in the agreement described above, pursuant to which BMS will provide, at no cost to us, nivolumab for use in our Phase 1 clinical trial of RP2 in combination with nivolumab.

Roche

In December 2022, we entered into a Master Clinical Trial Collaboration and Supply Agreement with Roche in relation to our RP2 and RP3 programs in colorectal cancer, or CRC, and hepatocellular carcinoma, or HCC. Under the agreement, the companies intended to collaborate in 30 patient cohort signal finding studies in third-line, or 3L, CRC and in first- and second-line, or 1L and 2L, respectively, HCC. Following our re-prioritization of our product development portfolio in December 2023, we have agreed with Roche to terminate the CRC collaboration and pursue the 2L cohort in HCC with RP2 only. Roche has continued to supply its currently approved drugs, atezolizumab and bevacizumab for the 2L cohort in HCC but is not sharing costs following our re-prioritization. Under the terms of the initial agreement we retained the responsibility of operating the

70

TABLE OF CONTENTS

clinical trials as well as retaining all the rights to the development and commercialization of our product candidates. The agreement may be terminated by either party upon sixty days prior written notice to the other party.

Critical accounting policies and estimates

Our management’s discussion and analysis of financial condition and results of operations is based on our consolidated financial statements, which have been prepared in accordance with generally accepted accounting principles in the United States. The preparation of our consolidated financial statements and related disclosures requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities, costs and expenses and the disclosure of contingent assets and liabilities in our consolidated financial statements. We base our estimates on historical experience, known trends and events and various other factors that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. We evaluate our estimates and assumptions on an ongoing basis. Our actual results may differ from these estimates under different assumptions or conditions.

While our significant accounting policies are described in greater detail in Note 2 to our consolidated financial statements appearing elsewhere in this Annual Report on Form 10-K, we believe that the following accounting policies are those most critical to the judgments and estimates used in the preparation of our consolidated financial statements.

Accrued research and development expenses

As part of the process of preparing our consolidated financial statements, we are required to estimate our accrued research and development expenses. This process involves reviewing open contracts and purchase orders, communicating with our personnel to identify services that have been performed on our behalf and estimating the level of service performed and the associated cost incurred for the service when we have not yet been invoiced or otherwise notified of actual costs. The majority of our service providers invoice us in arrears for services performed, on a pre-determined schedule or when contractual milestones are met; however, some require advanced payments. We make estimates of our accrued expenses as of each balance sheet date in the consolidated financial statements based on facts and circumstances known to us at that time. Examples of estimated accrued research and development expenses include fees paid to:

•CROs in connection with performing research activities and conducting preclinical studies and clinical trials on our behalf;

•CMOs in connection with the production of preclinical and clinical trial materials;

•investigative sites or other service providers in connection with clinical trials;

•vendors in connection with preclinical and clinical development activities; and

•vendors related to product manufacturing and development and distribution of preclinical and clinical supplies.

We base our expenses related to preclinical studies and clinical trials on our estimates of the services received and efforts expended pursuant to quotes and contracts with multiple CMOs and CROs that supply, conduct and manage preclinical studies and clinical trials on our behalf. The financial terms of these agreements are subject to negotiation, vary from contract to contract and may result in uneven payment flows. There may be instances in which payments made to our vendors will exceed the level of services provided and result in a prepayment of the expense. Payments under some of these contracts depend on factors such as the successful enrollment of patients and the completion of clinical trial milestones. In accruing service fees, we estimate the time period over which services will be performed and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from the estimate, we adjust the accrual or the amount of prepaid expenses accordingly. Although we do not expect our estimates to be materially different from amounts actually incurred, our understanding of the status and timing of services performed relative to the actual status and timing of services performed and/or timing of receiving invoices for actual services performed may vary and may result in reporting amounts that are too high or too low in any particular period. To date, there have not been any material adjustments to our prior estimates of accrued research and development expenses.

Stock-based compensation

We issue stock-based awards to employees, directors, consultants and non-employees in the form of stock options, restricted stock units, or RSUs, and performance-based restricted stock units, or PSUs. We measure such stock-based awards in accordance with ASC 718, Compensation — Stock Compensation, which requires all stock-based awards to be recognized in the consolidated statements of operations and comprehensive loss based on their fair value on the date of the grant and the related compensation expense for those awards is recognized over the requisite service period, which is generally the vesting period of

71

TABLE OF CONTENTS

the respective award. We have, to date, issued stock-based awards with service-based and performance-based vesting conditions. Expense for stock-based awards with service-based vesting conditions is recorded using the straight-line method and for PSUs with performance-based vesting conditions, the expense is recorded using the graded vesting method. The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes option-pricing model, which requires inputs based on certain subjective assumptions, including the expected stock price volatility, the expected term of the option, the risk-free interest rate for a period that approximates the expected term of the option, and our expected dividend yield. See Note 10 of the "Notes to Consolidated Financial Statements" contained in Part II, Item 8 of this Annual Report on Form 10-K for more information. Forfeitures are accounted for as they occur. The fair value of each RSU and PSU is estimated on the date of grant based on the fair value of our common stock on that same date.

We classify stock-based compensation expense in our consolidated statements of operations in the same manner in which the award recipient’s payroll costs are classified or in which the award recipient’s service payments are classified.

Recently issued accounting pronouncements

Refer to Note 2, Summary of significant accounting policies of the “Notes to Consolidated Financial Statements” contained in Part II, Item 8 of this Annual Report on Form 10-K for a description of recent accounting pronouncements that are applicable to our business and may potentially have an impact on our financial position and results of operations.

Item 7.    Management’s discussion and analysis of financial condition and results of operations

You should read the following discussion and analysis of our financial condition and results of operations in conjunction with our consolidated financial statements and related notes and other financial information included elsewhere in this Annual Report on Form 10-K. In addition to historical information, some of the statements contained in this discussion and analysis or set forth elsewhere in this Annual Report on Form 10-K, including information with respect to our plans and strategy for our business, constitute forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act. We have based these forward-looking statements on our current expectations and projections about future events. The following information and any forward-looking statements should be considered in light of factors discussed elsewhere in this Annual Report on Form 10-K, particularly including those risks identified in Part I, Item 1A “Risk factors” and our other filings with the SEC.

We caution you that forward-looking statements are not guarantees of future performance and that our actual results of operations, financial condition and liquidity, and the development of the industry in which we operate may differ materially from the forward-looking statements contained in this Annual Report on Form 10-K. Statements made herein are as of the date of the filing of this Annual Report on Form 10-K with the SEC and should not be relied upon as of any subsequent date. Even if our results of operations, financial condition and liquidity, and the development of the industry in which we operate are consistent with the forward-looking statements contained in this Annual Report on Form 10-K, they may not be predictive of results or developments in future periods. We disclaim any obligation, except as specifically required by law and the rules of the SEC, to publicly update or revise any such statements to reflect any change in our expectations or in events, conditions or circumstances on which any such statements may be based or that may affect the likelihood that actual results will differ from those set forth in the forward-looking statements.

Overview

We are a clinical-stage biotechnology company committed to applying our leading expertise in the field of oncolytic immunotherapy to transform the lives of cancer patients through our novel oncolytic immunotherapies. Our proprietary

60

TABLE OF CONTENTS

oncolytic immunotherapy product candidates are designed and intended to maximally activate the immune system against cancer.

Oncolytic immunotherapy is an emerging drug class, which we intend to establish as the second cornerstone of immune-based cancer treatments, alongside checkpoint blockade. Oncolytic immunotherapy exploits the ability of certain viruses to selectively replicate in and directly kill tumors, as well as induce a potent, patient-specific, anti-tumor immune response. Our product candidates incorporate multiple mechanisms into a practical “off-the-shelf” approach that is intended to maximize the immune response against a patient’s cancer and to offer significant advantages over other approaches of inducing anti-tumor immunity, including personalized vaccine approaches. We believe that the bundling of multiple approaches for the treatment of cancer into single therapies may improve patient outcomes and simplify the development path of our product candidates.

Financial

Since our inception, we have devoted substantially all of our resources to developing our proprietary RPx platform, building our intellectual property portfolio, conducting research and development of our product candidates, business planning, raising capital and providing selling, general and administrative support for our operations. To date, we have incurred significant operating losses and we have financed our operations primarily with proceeds from the sale of equity securities and to a lesser extent the proceeds from the issuance of debt securities. Our ability to generate product revenue sufficient to achieve profitability will depend on the successful development and eventual commercialization, if approved, of one or more of our product candidates. We do not have any products approved for sale and have not generated any revenue from product sales.

Since our initial public offering, or IPO, on July 20, 2018, we have raised an aggregate of approximately $849.1 million in net proceeds to fund our operations, of which $101.2 million was from our IPO, $706.0 million was from four separate follow-on offerings, or the Public Offerings, that we closed in November 2019, June 2020, October 2020 and December 2022, respectively, and $41.9 million was from at-the-market offerings.

Our net losses were $215.8 million and $174.3 million for the years ended March 31, 2024 and 2023, respectively. As of March 31, 2024, we had an accumulated deficit of $701.3 million. These losses have resulted primarily from costs incurred in connection with research and development activities and selling, general and administrative costs associated with our operations. We expect to continue to incur significant expenses and increasing operating losses for at least the next several years.

We anticipate that our expenses and capital requirements will fluctuate from period to period depending upon the Company's development programs and priorities. We expect to continue to incur costs in connection with our ongoing development activities, including further advancement of any preclinical activities and clinical trials of our product candidates across our platform, and if and as we:

•conduct our current and future clinical trials;

•further preclinical development of our platform;

•operate our in-house manufacturing facility;

•seek to identify and develop additional product candidates;

•seek marketing approvals for any of our product candidates that successfully complete clinical trials, if any;

•establish a sales, marketing and distribution infrastructure to commercialize any products for which we may obtain marketing approval;

•until our manufacturing facility is fully validated, continued limited manufacturing by third parties for clinical development;

•maintain, expand and protect our intellectual property portfolio;

•hire and retain additional clinical, quality control, scientific and selling, general and administration personnel;

•acquire or in-license other drugs, technologies or intellectual property rights; and

•add operational, financial and management information systems and personnel, including personnel to support our research and development programs, any future commercialization efforts and operations as a public company.

Because of the numerous risks and uncertainties associated with pharmaceutical product development, we are unable to accurately predict the timing or amount of increased expenses or when, or if, we will be able to achieve or maintain profitability. Even if we are able to generate product sales, we may not become profitable. If we fail to become profitable or are

61

TABLE OF CONTENTS

unable to sustain profitability on a continuing basis, then we may be unable to continue our operations at planned levels and be forced to reduce or terminate our operations.

As of March 31, 2024, we had cash and cash equivalents and short-term investments of $420.7 million. Based on our current operating plan, we believe that our existing cash and cash equivalents and short-term investments will enable us to fund our operating expenses and capital expenditure requirements through at least 12 months from the issuance of the consolidated financial statements included in this Annual Report on Form 10-K.

See “Results of Operations — Liquidity and capital resources” and “Risk factors — Risks related to our financial position and need for additional capital.”

Components of our results of operations

Revenue

To date, we have not generated any revenue from product sales as we do not have any approved products and do not expect to generate any revenue from the sale of products in the near future. If our development efforts for RP1 or any other product candidates that we may develop in the future are successful and result in regulatory approval, or if we enter into collaboration or license agreements with third parties, we may generate revenue in the future from a combination of product sales or payments from those collaborations or license agreements.

Operating expenses

Research and development expenses

Research and development expenses consist primarily of costs incurred for our research activities, including our discovery efforts and the development of our product candidates, and include:

•expenses incurred under agreements with third parties, including CROs, that conduct research, preclinical activities and clinical trials on our behalf as well as CMOs that manufacture our raw materials and/or product candidates for use in our preclinical and clinical trials;

•salaries, benefits and other related costs, including stock-based compensation expense, for personnel engaged in research and development functions;

•costs of outside consultants engaged in research and development functions, including their fees, stock-based compensation and related travel expenses;

•the costs of laboratory supplies and acquiring, developing and manufacturing preclinical study and clinical trial materials;

•costs related to compliance with regulatory requirements in connection with the development of our product candidates; and

•facility-related expenses, which include direct depreciation costs and allocated expenses for rent and maintenance of facilities and other operating costs.

We expense research and development costs as incurred. We recognize external development costs based on an evaluation of the progress to completion of specific tasks using information provided to us by our service providers. Payments for these activities are based on the terms of the individual agreements, which may differ from the pattern of costs incurred, and are reflected in our consolidated financial statements as prepaid or accrued research and development expenses.

Our direct external research and development expenses are tracked on a program-by-program basis and consist of costs, such as fees paid to consultants, contractors, CMOs, and CROs in connection with our preclinical and clinical development activities. We do not allocate personnel costs, costs associated with our discovery efforts, laboratory supplies or other indirect costs, to specific product development programs because these costs are deployed across multiple product development programs and, as such, are not separately classified. Non-employee costs associated with our manufacturing facility including depreciation, amortization and facility costs are appropriately allocated to development programs based on the percentage of time spent per program.

Research and development activities are central to our business model. Product candidates in later stages of clinical development generally have higher development costs than those in earlier stages of clinical development, primarily due to the increased size and duration of later-stage clinical trials. We expect that our research and development expenses will continue to increase for the foreseeable future as we continue enrollment and initiate additional clinical trials and continue to discover and

62

TABLE OF CONTENTS

develop additional product candidates. The successful development and commercialization of our product candidates is highly uncertain. This is due to the numerous risks and uncertainties associated with product development and commercialization, including the following:

•the scope, rate of progress, expense and results of our ongoing clinical trials, as well as future clinical trials or other product candidates and other research and development activities that we may conduct;

•the number and scope of preclinical and clinical programs we decide to pursue;

•our ability to maintain our current research and development programs and to establish new ones;

•uncertainties in clinical trial design;

•the rate of enrollment in clinical trials;

•the successful completion of clinical trials with safety, tolerability, and efficacy profiles that are satisfactory to the FDA or any comparable foreign regulatory authority;

•the receipt of regulatory approvals from applicable regulatory authorities;

•our success in operating our manufacturing facility, or securing manufacturing supply through relationships with third parties;

•our ability to obtain and maintain patents, trade secret protection, and regulatory exclusivity, both in the United States and internationally;

•our ability to maintain, expand and protect our rights in our intellectual property portfolio;

•the commercialization of our product candidates, if and when approved;

•the acceptance of our product candidates, if approved, by patients, the medical community, and third-party payors;

•our ability to successfully develop our product candidates for use in combination with third-party products or product candidates;

•negative developments in the field of immuno-oncology;

•competition with other products; and

•significant and changing government regulation and regulatory guidance.

A change in the outcome of any of these variables with respect to the development of a product candidate could mean a significant change in the costs and timing associated with the development of that product candidate. For example, if the FDA or another regulatory authority were to require us to conduct clinical trials beyond those that we anticipate will be required for the completion of clinical development of a product candidate, or if we experience significant trial delays due to patient enrollment or other reasons, we could be required to expend significant additional financial resources and time on the completion of clinical development. We may never succeed in obtaining regulatory approval for any of our product candidates.

Selling, general and administrative expenses

Selling, general and administrative expenses consist primarily of salaries and other related costs, including stock-based compensation, for personnel in our executive, finance, corporate, commercial, and business development and administrative functions. Selling, general and administrative expenses also include professional fees for legal, patent, accounting, auditing, tax and consulting services, pre-commercial planning, marketing and strategic planning, business development, travel expenses, and facility-related expenses, which include direct depreciation costs and allocated expenses for rent and maintenance of facilities and other operating costs.

We expect that our selling, general and administrative expenses will continue to increase in the future as we increase our selling, general and administrative headcount to support our continued research and development and pre-launch activities to prepare for potential commercialization of our product candidates. We also expect to continue to incur increased expenses, including accounting, audit, legal, regulatory and tax-related services associated with maintaining compliance with exchange listing and SEC requirements; director and officer insurance costs; and investor and public relations costs.

Other income (expense), net

Research and development incentives

63

TABLE OF CONTENTS

Research and development incentives consists of reimbursements of research and development expenditures. We participate, through our subsidiary in the United Kingdom, in the research and development program provided by the United Kingdom tax relief program, such that a percentage of up to 14.5% of our qualifying research and development expenditures are reimbursed by the United Kingdom government, and such incentives are reflected as other income.

Investment income

Investment income consists of income earned on our cash and cash equivalents and short-term investments.

Interest expense on finance lease liability

Interest expense on finance lease liability consists of amortization of finance charges under our financing lease.

Interest expense on debt obligations

Interest expense on debt obligations consists of the amortization of debt discount and cash paid for interest under the Hercules Loan Agreement.

Other income (expense), net

Other income (expense), net consists primarily of realized and unrealized foreign currency transaction gains and losses.

Income taxes

During the year ended March 31, 2024 and 2023, the Company recorded an income tax provision of $0.4 million and $0.3 million, respectively, related to U.S. current taxes primarily due to the transfer pricing arrangement between the U.S. and the U.K., as well as unfavorable adjustments related to stock compensation, resulting in U.S. taxable income reduced by certain prior year available net operating losses.

Results of operations

Comparison of the years ended March 31, 2024 and 2023

The following table summarizes our results of operations for the years ended March 31, 2024 and 2023:

64

TABLE OF CONTENTS

Research and development expenses

Research and development expenses for the year ended March 31, 2024 were $175.0 million, compared to $126.5 million for the year ended March 31, 2023. The following table summarizes our research and development expenses for the years ended March 31, 2024 and 2023:

The total increase of $48.4 million was due to an increase of approximately $18.7 million in direct research costs related to our ongoing clinical trials and increased patient enrollment for RP1, RP2 and RP3, including an increase of approximately $13.3 million in the areas of CRO costs, investigator costs, and imaging costs. The costs for RP1 also increased compared to the prior year as we prepared the primary analysis and preparations for a potential BLA filing for CERPASS as well as the initial full data presentation for IGNYTE and preparations for a potential BLA submission for IGNYTE. In addition, we focused on an updated data presentation on the ARTACUS trial. Furthermore, we continued to ramp up activities to develop RP2 throughout the year ended March 31, 2024 as compared to the prior year, whereas activities for RP3 remained consistent year over year as a result of the deprioritization of development efforts on this product candidate during the later part of fiscal 2024.

The increase of $29.7 million in our unallocated expenses was due primarily to a $26.8 million increase in personnel-related costs, including a $22.1 million increase in payroll and fringe benefits and a stock-based compensation increase of $4.7 million. The increase in personnel-related costs largely reflected the hiring of additional personnel in our research and development functions as we expand the development plan in multiple indications. Personnel related costs for the years ended March 31, 2024 and 2023 included stock-based compensation expense of $14.7 million and $10.1 million, respectively.

Selling, general and administrative expenses

Selling, general and administrative expenses were $59.8 million for the year ended March 31, 2024, compared to $50.6 million for the year ended March 31, 2023. The increase of $9.3 million is primarily the result of an increase of $6.3 million in personnel related costs, including an increase of $5.0 million in payroll and fringe benefits and a stock-based compensation increase of $1.3 million. The increase in personnel related costs was driven by the continued hiring of additional personnel within our selling, general and administrative functions, specifically focusing on commercial planning and building of our initial commercial infrastructure. Personnel related costs for the year ended March 31, 2024 and 2023 included stock-based compensation expense of $19.4 million and $18.1 million, respectively.

Total other income (expense), net

Other income for the year ended March 31, 2024 was $19.4 million compared to $3.1 million for the year ended March 31, 2023. The net change of $16.3 million is primarily attributable to an increase of $13.4 million in investment income in the current year as compared to the prior year as a result of increases in interest rates throughout the year, as well as a $6.4 million decrease in expense due to the changes in foreign exchange rates of the Great British Pound to United States Dollar. These increases were partially offset by an increase in expense of $2.5 million of interest expense on debt obligations, as the Company drew down an additional term loan advance of $15.0 million in December 2023 from the debt agreement with Hercules.

Income tax provision

Income tax provision for the year ended March 31, 2024 was $0.4 million compared to $0.3 million for the year ended March 31, 2023. The income tax provision for the current year is attributable to U.S. current taxes primarily due to the transfer pricing arrangement between the U.S. and the U.K., as well as unfavorable adjustments related to stock compensation, resulting in U.S. taxable income reduced by certain prior year available net operating losses.

65

TABLE OF CONTENTS

Liquidity and capital resources

Since our inception, we have not generated any revenue from product sales and have incurred significant operating losses and negative cash flows from our operations. We have not yet commercialized any of our product candidates, which are in various phases of preclinical and clinical development, and we do not expect to generate revenue from sales of any products for the foreseeable future, if at all.

Sources of liquidity

To date, we have financed our operations primarily with proceeds from the sale of equity securities and, to a lesser extent, proceeds from borrowing under a secured loan facility. Through March 31, 2024, we had received net proceeds of $935.9 million through the sale of equity securities, as well as net $42.8 million from our incurrence of debt under the Hercules Loan Agreement. As of March 31, 2024, we had cash and cash equivalents and short-term investments of $420.7 million.

Cash flows

The following table summarizes our cash flows for each of the periods presented:

Operating activities

During the year ended March 31, 2024, net cash used in operating activities was $185.5 million, primarily resulting from our net loss of $215.8 million, which was partially offset by non-cash charges of $24.8 million, consisting primarily of stock-based compensation expense of $34.1 million offset by $12.3 million related to the net amortization of premiums and discounts on short-term investments. Additionally, there was an increase in cash of $5.5 million related to changes in our operating assets and liabilities. Changes in our operating assets and liabilities for the year ended March 31, 2024 consisted primarily of a $9.2 million increase in accrued expenses and other current liabilities, a $2.8 million decrease in accounts payable, and a net $2.4 million change in operating and financing right-of-use assets and lease liabilities.

During the year ended March 31, 2023, net cash used in operating activities was $128.1 million, primarily resulting from our net loss of $174.3 million, partially offset by non-cash charges of $31.1 million, consisting primarily of stock-based compensation expense of $28.1 million, and an increase in cash of $15.1 million related to changes in our operating assets and liabilities. Changes in our operating assets and liabilities for the year ended March 31, 2023 consisted primarily of a $11.4 million increase in accrued expenses and other current liabilities, a net $2.4 million change in operating and financing right-of-use assets and lease liabilities, and a $2.0 million increase in accounts payable.

Investing activities

During the year ended March 31, 2024, net cash provided by investing activities was $97.2 million, consisting of $592.4 million in proceeds from sales and maturities of short-term investments, partially offset by $489.5 million in purchases of available for sale securities and $5.7 million in purchases of property, plant and equipment.

During the year ended March 31, 2023, net cash used in investing activities was $142.5 million, consisting of $583.4 million in purchases of available for sale securities and $2.3 million in purchases of property, plant and equipment, offset by $443.2 million in proceeds from sales and maturities of short-term investments.

Financing Activities

During the year ended March 31, 2024, net cash provided by financing activities was $16.3 million, consisting primarily of $15.0 million in proceeds from the incurrence of debt under the Hercules Loan Agreement, as well as approximately $1.8 million in proceeds from the exercise of stock options.

66

TABLE OF CONTENTS

During the year ended March 31, 2023, net cash provided by financing activities was $311.3 million, consisting primarily of $149.9 million in proceeds from the issuance of common stock, $92.8 million from the issuance of pre-funded warrants to purchase common stock, $37.4 million from the issuance of common stock through sales under our at-the-market facilities, $28.2 million in proceeds from the incurrence of debt under the Hercules Loan Agreement, as well as approximately $3.4 million in proceeds from the exercise of stock options.

Funding requirements

Our plan of operation is to continue implementing our business strategy, continue research and development of RP1 and our other product candidates and continue to expand our research pipeline and our internal research and development capabilities. We expect our expenses to increase substantially in connection with our ongoing activities, particularly as we advance the preclinical activities and clinical trials of our product candidates and if and as we:

•conduct our current and future clinical trials with RP1, RP2 and RP3;

•further preclinical development of our RPx platform;

•operate, qualify and maintain our in-house manufacturing facility and qualify and maintain our product candidates made therein for use in our clinical trials;

•seek to identify and develop additional product candidates;

•seek marketing approvals for any of our product candidates that successfully complete clinical trials, if any;

•establish a sales, marketing and distribution infrastructure to commercialize any products for which we may obtain marketing approval;

•until our planned manufacturing facility is fully validated, continued limited manufacturing by third parties for clinical development;

•maintain, expand and protect our intellectual property portfolio;

•acquire or in-license other drugs, technologies or third-party intellectual property; and

•add operational, financial and management information systems and personnel, including personnel to support our research and development programs, any future commercialization efforts and operations as a public company.

As of March 31, 2024, we had cash and cash equivalents and short-term investments of $420.7 million. Based on our current operating plan, we believe that our existing cash, cash equivalents and short-term investments as of March 31, 2024, will enable us to fund operations into the second half of 2026. We have based these estimates on assumptions that may prove to be wrong, and we could utilize our available capital resources sooner than we expect.

Because of the numerous risks and uncertainties associated with the development of RP1 and other product candidates and programs, and because the extent to which we may enter into collaborations with third parties for development of our product candidates is unknown, we are unable to estimate the timing and amounts of increased capital outlays and operating expenses associated with completing the research and development of our product candidates. Our future capital requirements will depend on many factors, including those described in this section and above under “— Operating expenses — Research and development expenses.”

Developing novel biopharmaceutical products, including conducting preclinical studies and clinical trials, is a time-consuming, expensive and uncertain process that takes years to complete, and we may never generate the necessary data or results required to obtain marketing approval for any product candidates or generate revenue from the sale of any products for which we may obtain marketing approval. In addition, our product candidates, if approved, may not achieve commercial success. Our commercial revenues, if any, will be derived from sales of therapies that we do not expect to be commercially available for many years, if ever. Accordingly, we will need to obtain substantial additional funds to achieve our business objectives.

Adequate additional funds may not be available to us on acceptable terms, or at all. We do not currently have any committed external source of funds. To the extent that we raise additional capital through the sale of our equity or convertible debt securities, our shareholders’ interest may be diluted, and the terms of these securities may include liquidation or other preferences and anti-dilution protections that could adversely affect the rights of our common stockholder. Additional debt or preferred equity financing, if available, may involve agreements that include restrictive covenants that may limit our ability to take specific actions, such as incurring debt, adversely impact our ability to conduct our business, and may require the issuance of warrants, which could potentially dilute your ownership interest.

67

TABLE OF CONTENTS

If we raise additional funds through collaborations, strategic alliances or licensing arrangements with third parties, we may have to relinquish valuable rights to our technology, future revenue streams, research programs, or product candidates or grant licenses on terms that may not be favorable to us. If we are unable to raise additional funds through equity or debt financings or collaborations, strategic alliances or licensing arrangements with third parties when needed, we may be required to delay, limit, reduce and/or terminate our product development programs or any future commercialization efforts or grant rights to develop and market product candidates that we would otherwise prefer to develop and market ourselves.

Contractual obligations and commitments

We have entered into arrangements that contractually obligate us to make payments that will affect our liquidity and cash flows in future periods. Our contractual obligations include those related to our operating and financing leases, long-term debt, as well as costs associated with contracts entered into in the normal course of business with CROs, CMOs and other third parties for clinical trials and preclinical research studies and testing.

Lease Commitments

As of March 31, 2024, the aggregate amount of future lease payments is approximately $52.9 million, with $3.9 million due within one year. For additional information on our leases and timing of future payments, see Note 13 Commitments and contingencies, of the "notes to Consolidated Financial Statements" contained in Part II, Item 8 of this Annual Report on Form 10-K.

Loan Agreement

Our commitments due for our term loan under our arrangement with Hercules include principal payments of $45.0 million as of March 31, 2024. Borrowings under the term loan agreement are repayable in monthly interest-only payments through September 2026, and the agreement has a maturity date of October 2027. Our remaining commitments, based on our current draws, are due through October 2027, and include principal and interest payments of $62.2 million, and an additional fee upon maturity of the loan of $2.2 million. See Note 7, Long term debt, of the "notes to Consolidated Financial Statements" contained in Part II, Item 8 of this Annual Report on Form 10-K for further discussion of the Hercules term loan.

Other Obligations

Manufacturing and research commitments include agreements that are enforceable and legally binding on us and that specify all significant terms, including fixed or minimum quantities to be purchased; fixed, minimum or variable price provisions; and the approximate timing of the transaction. As of March 31, 2024, the aggregate amount of non-cancelable purchase obligations related to such manufacturing commitments are approximately $0.9 million and all of this balance is due within one year.

Collaborations

BMS

In February 2018, we entered into a Clinical Trial Collaboration and Supply Agreement with Bristol-Myers Squibb Company, or BMS. Pursuant to the agreement, BMS is providing to us, at no cost, nivolumab, its anti-PD-1 therapy, for use in combination with RP1 in our ongoing Phase 1/2 clinical trial. Under the agreement, we will sponsor, fund and conduct the clinical trial in accordance with an agreed-upon protocol. BMS granted us a non-exclusive, non-transferrable, royalty-free license (with a right to sublicense) under its intellectual property to use nivolumab in the clinical trial and has agreed to supply nivolumab, at no cost to us, for use in the clinical trial. Both parties will own the study data produced in the clinical trial, other than study data related solely to nivolumab, which will belong solely to BMS, or study data related solely to RP1, which will belong solely to us. In January 2020, this agreement was expanded to cover an additional cohort of 125 patients with anti-PD-1 failed melanoma.

Unless earlier terminated, the agreement will remain in effect until (i) the completion of the clinical trial, (ii) all related clinical trial data have been delivered to both parties and (iii) the completion of any statistical analyses and bioanalyses contemplated by the clinical trial protocol or any analysis otherwise agreed upon by the parties. The agreement may be terminated by either party (x) in the event of an uncured material breach by the other party, (y) in the event the other party is insolvent or in bankruptcy proceedings or (z) for safety reasons. Upon termination, the licenses granted to us to use nivolumab in the clinical trial will terminate. The agreement contains representations, warranties, undertakings and indemnities customary for a transaction of this nature.

68

TABLE OF CONTENTS

In April 2019, we entered into a separate agreement with BMS on terms similar to the terms set forth in the agreement described above, pursuant to which BMS will provide, at no cost to us, nivolumab for use in our Phase 1 clinical trial of RP2 in combination with nivolumab.

Regeneron

In May 2018, we entered into a Master Clinical Trial Collaboration and Supply Agreement with Regeneron. Pursuant to the agreement we agreed to undertake one or more clinical trials with Regeneron for the administration of our product candidates in combination with cemiplimab, an anti-PD-1 therapy developed by Regeneron, across multiple solid tumor types, the first of which is our ongoing Phase 2 clinical trial testing RP1 in combination with cemiplimab versus cemiplimab alone in patients with CSCC. Each clinical trial will be conducted pursuant to an agreed study plan which, among other things, will identify the name of the sponsor and which party will manage the particular study, and include the protocol, the budget and a schedule of clinical obligations.

Pursuant to the terms of the agreement, each party granted the other party a non-exclusive license of their respective intellectual property and agreed to contribute the necessary resources needed to fulfill their respective obligations, in each case, under the terms of agreed study plans. The Company does not expect any further reimbursements from Regeneron related to the initial study plan of June 2018 and the CERPASS trial. The agreement contains representations, warranties, undertakings and indemnities customary for a transaction of this nature. The agreement also contains certain time-based covenants that restrict us from entering into a third-party arrangement with respect to the use of our product candidates in combination with an anti-PD-1 therapy and that restrict Regeneron from entering into a third-party arrangement with respect to the use of cemiplimab in combination with an HSV-1 virus, in each case, for the treatment of a tumor type that is the subject of a clinical trial to which the covenants apply. Unless otherwise mutually agreed in a future study plan, these covenants are only applicable to our ongoing Phase 2 clinical trial in CSCC.

The agreement may be terminated by either party if (i) there is no active study plan for which a final study report has not been completed and the parties have not entered into a study plan for an additional clinical trial within a period of time after the delivery of the most recent final study report or (ii) in the event of a material breach.

Roche

In December 2022, we entered into a Master Clinical Trial Collaboration and Supply Agreement with Roche in relation to our RP2 and RP3 programs in colorectal cancer, or CRC, and hepatocellular carcinoma, or HCC. Under the agreement, the companies intended to collaborate in 30 patient cohort signal finding studies in third-line, or 3L, CRC and in first- and second-line, or 1L and 2L, respectively, HCC. Following our re-prioritization of our product development portfolio in December 2023, we have agreed with Roche to terminate the CRC collaboration and pursue the 2L cohort in HCC with RP2 only. Roche has expressed its intent to continue to supply its currently approved drugs, atezolizumab and bevacizumab for the 2L cohort in HCC but is unlikely to share costs following our re-prioritization. We are in discussions with Roche about revising these agreements following our changes to our RP2 and RP3 development plans. Under the terms of the initial agreement we retained the responsibility of operating the clinical trials as well as retaining all the rights to the development and commercialization of our product candidates. The agreement may be terminated by either party upon sixty days prior written notice to the other party.

Incyte

In July 2023, we entered into a Clinical Trial Collaboration and Supply Agreement with Incyte Corporation, or Incyte. Under the agreement, the companies will collaborate in a signal finding study in which Incyte will initiate and sponsor a clinical trial of INCB99280 (oral PD-L1 inhibitor) and RP1 in approximately 40 patients with unresectable, high risk CSCC in the neoadjuvant setting. Under the terms of the agreement, we will supply Incyte with RP1 for the study and share costs of the study equally with Incyte. The agreement may be terminated by either party upon (i) a material breach not reasonably cured within thirty days; (ii) the discontinuation of development of its clinical drug candidate; (iii) the unethical or illegal business practices of the other party; or (iv) if the parties have not agreed on the protocol or budget within ninety days of the effective date of the agreement. In addition, the Company may terminate the agreement upon the inappropriate or unsafe use of the RP1 product candidate. As of March 31, 2024, we and Incyte had not yet agreed on the protocol or budget. However, we and Incyte continue to discuss a potential protocol and neither party has triggered termination of the agreement in accordance with the termination right described in clause (iv) above. The parties are evaluating potential collaboration efforts pending further CERPASS data readout of RP1 in combination with cemiplimab and additional data for Incyte's product candidate INCB99280.

Critical accounting policies and estimates

Our management’s discussion and analysis of financial condition and results of operations is based on our consolidated financial statements, which have been prepared in accordance with generally accepted accounting principles in the United

69

TABLE OF CONTENTS

States. The preparation of our consolidated financial statements and related disclosures requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities, costs and expenses and the disclosure of contingent assets and liabilities in our consolidated financial statements. We base our estimates on historical experience, known trends and events and various other factors that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. We evaluate our estimates and assumptions on an ongoing basis. Our actual results may differ from these estimates under different assumptions or conditions.

While our significant accounting policies are described in greater detail in Note 2 to our consolidated financial statements appearing elsewhere in this Annual Report on Form 10-K, we believe that the following accounting policies are those most critical to the judgments and estimates used in the preparation of our consolidated financial statements.

Accrued research and development expenses

As part of the process of preparing our consolidated financial statements, we are required to estimate our accrued research and development expenses. This process involves reviewing open contracts and purchase orders, communicating with our personnel to identify services that have been performed on our behalf and estimating the level of service performed and the associated cost incurred for the service when we have not yet been invoiced or otherwise notified of actual costs. The majority of our service providers invoice us in arrears for services performed, on a pre-determined schedule or when contractual milestones are met; however, some require advanced payments. We make estimates of our accrued expenses as of each balance sheet date in the consolidated financial statements based on facts and circumstances known to us at that time. Examples of estimated accrued research and development expenses include fees paid to:

•CROs in connection with performing research activities and conducting preclinical studies and clinical trials on our behalf;

•CMOs in connection with the production of preclinical and clinical trial materials;

•investigative sites or other service providers in connection with clinical trials;

•vendors in connection with preclinical and clinical development activities; and

•vendors related to product manufacturing and development and distribution of preclinical and clinical supplies.

We base our expenses related to preclinical studies and clinical trials on our estimates of the services received and efforts expended pursuant to quotes and contracts with multiple CMOs and CROs that supply, conduct and manage preclinical studies and clinical trials on our behalf. The financial terms of these agreements are subject to negotiation, vary from contract to contract and may result in uneven payment flows. There may be instances in which payments made to our vendors will exceed the level of services provided and result in a prepayment of the expense. Payments under some of these contracts depend on factors such as the successful enrollment of patients and the completion of clinical trial milestones. In accruing service fees, we estimate the time period over which services will be performed and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from the estimate, we adjust the accrual or the amount of prepaid expenses accordingly. Although we do not expect our estimates to be materially different from amounts actually incurred, our understanding of the status and timing of services performed relative to the actual status and timing of services performed and/or timing of receiving invoices for actual services performed may vary and may result in reporting amounts that are too high or too low in any particular period. To date, there have not been any material adjustments to our prior estimates of accrued research and development expenses.

Stock-based compensation

We issue stock-based awards to employees, directors, consultants and non-employees in the form of stock options, restricted stock units, and performance-based restricted stock units, or PSUs. We measure such stock-based awards in accordance with ASC 718, Compensation — Stock Compensation, which requires all stock-based awards to be recognized in the consolidated statements of operations and comprehensive loss based on their fair value on the date of the grant and the related compensation expense for those awards is recognized over the requisite service period, which is generally the vesting period of the respective award. We have, to date, issued stock-based awards with service-based and performance-based vesting conditions. Expense for stock-based awards with service-based vesting conditions is recorded using the straight-line method and for PSUs with performance-based vesting conditions, the expense is recorded using the graded vesting method. The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes option-pricing model, which requires inputs based on certain subjective assumptions, including the expected stock price volatility, the expected term of the option, the risk-free interest rate for a period that approximates the expected term of the option, and our expected dividend yield. See Note 10 of the "Notes to Consolidated Financial Statements" contained in Part II, Item 8 of this Annual Report on Form 10-K

70

TABLE OF CONTENTS

for more information. Forfeitures are accounted for as they occur. The fair value of each RSU and PSU is estimated on the date of grant based on the fair value of our common stock on that same date.

We classify stock-based compensation expense in our consolidated statements of operations in the same manner in which the award recipient’s payroll costs are classified or in which the award recipient’s service payments are classified.

Recently issued accounting pronouncements

Refer to Note 2, summary of significant accounting policies of the “Notes to Consolidated Financial Statements” contained in Part II, Item 8 of this Annual Report on Form 10-K for a description of recent accounting pronouncements that are applicable to our business and may potentially have an impact on our financial position and results of operations.

Item 7.    Management’s discussion and analysis of financial condition and results of operations

You should read the following discussion and analysis of our financial condition and results of operations in conjunction with our consolidated financial statements and related notes and other financial information included elsewhere in this Annual Report on Form 10-K. In addition to historical information, some of the statements contained in this discussion and analysis or set forth elsewhere in this Annual Report on Form 10-K, including information with respect to our plans and strategy for our business, constitute forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act. We have based these forward-looking statements on our current expectations and projections about future events. The following information and any forward-looking statements should be considered in light of factors discussed elsewhere in this Annual Report on Form 10-K, particularly including those risks identified in Part I, Item 1A “Risk factors” and our other filings with the SEC.

We caution you that forward-looking statements are not guarantees of future performance and that our actual results of operations, financial condition and liquidity, and the development of the industry in which we operate may differ materially from the forward-looking statements contained in this Annual Report on Form 10-K. Statements made herein are as of the date of the filing of this Annual Report on Form 10-K with the SEC and should not be relied upon as of any subsequent date. Even if our results of operations, financial condition and liquidity, and the development of the industry in which we operate are consistent with the forward-looking statements contained in this Annual Report on Form 10-K, they may not be predictive of results or developments in future periods. We disclaim any obligation, except as specifically required by law and the rules of the SEC, to publicly update or revise any such statements to reflect any change in our expectations or in events, conditions or circumstances on which any such statements may be based or that may affect the likelihood that actual results will differ from those set forth in the forward-looking statements.

Overview

We are a clinical-stage biotechnology company committed to applying our leading expertise in the field of oncolytic immunotherapy to transform the lives of cancer patients through our novel tumor-directed oncolytic immunotherapies. Our

59

TABLE OF CONTENTS

proprietary tumor-directed oncolytic immunotherapy product candidates are designed and intended to maximally activate the immune system against cancer.

Oncolytic immunotherapy is an emerging drug class, which we intend to establish as the second cornerstone of immune-based cancer treatments, alongside checkpoint blockade. Oncolytic immunotherapy exploits the ability of certain viruses to selectively replicate in and directly kill tumors, as well as induce a potent, patient-specific, anti-tumor immune response. Our product candidates incorporate multiple mechanisms of action into a practical “off-the-shelf” approach that is intended to maximize the immune response against a patient’s cancer and to offer significant advantages over other approaches of inducing anti-tumor immunity, including personalized vaccine approaches. We believe that the bundling of multiple approaches for the treatment of cancer into single therapies will simplify the development path of our product candidates, while also improving patient outcomes at a lower cost to the healthcare system than the use of multiple different drugs.

Financial

Since our inception, we have devoted substantially all of our resources to developing our proprietary RPx platform, building our intellectual property portfolio, conducting research and development of our product candidates, business planning, raising capital and providing selling, general and administrative support for our operations. To date, we have incurred significant operating losses and we have financed our operations primarily with proceeds from the sale of equity securities and to a lesser extent the proceeds from the issuance of debt securities. Our ability to generate product revenue sufficient to achieve profitability will depend on the successful development and eventual commercialization of one or more of our product candidates. We do not have any products approved for sale and have not generated any revenue from product sales.

Since our initial public offering, or IPO, on July 20, 2018, we have raised an aggregate of approximately $849.1 million in net proceeds to fund our operations, of which $101.2 million was from our IPO, $706.0 million was from four separate follow-on offerings, or the Public Offerings, that we closed in November 2019, June 2020, October 2020 and December 2022, respectively, and $41.9 million was from at-the-market offerings. We sold 7,407,936 shares of common stock in our IPO, an aggregate of 20,430,480 shares of our common stock and pre-funded warrants to purchase 9,484,238 shares of common stock in the Public Offerings, and 2,313,997 shares of common stock through our at-the-market facilities.

Our net losses were $174.3 million and $118.0 million for the years ended March 31, 2023 and 2022, respectively. As of March 31, 2023, we had an accumulated deficit of $485.5 million. These losses have resulted primarily from costs incurred in connection with research and development activities and selling, general and administrative costs associated with our operations. We expect to continue to incur significant expenses and increasing operating losses for the next several years and our ability to generate product revenue sufficient to achieve profitability will depend on the successful development and commercialization of one or more of our product candidates.

We anticipate that our expenses and capital requirements will increase substantially in connection with our ongoing activities, particularly as we advance the clinical trials, development and pre-commercial activities related to our RPx platform product candidates, and if and as we:

•conduct our current and future clinical trials with RP1, RP2 and RP3;

•further preclinical development of our platform;

•operate our in-house manufacturing facility;

•seek to identify and develop additional product candidates;

•seek marketing approvals for any of our product candidates that successfully complete clinical trials, if any;

•establish a sales, marketing and distribution infrastructure to commercialize any products for which we may obtain marketing approval;

•until our manufacturing facility is fully validated, continued limited manufacturing by third parties for clinical development;

•maintain, expand and protect our intellectual property portfolio;

•hire and retain additional clinical, quality control, scientific and selling, general and administration personnel;

•acquire or in-license other drugs, technologies or intellectual property rights; and

•add operational, financial and management information systems and personnel, including personnel to support our research and development programs, any future commercialization efforts and operations as a public company.

60

TABLE OF CONTENTS

Because of the numerous risks and uncertainties associated with pharmaceutical product development, we are unable to accurately predict the timing or amount of increased expenses or when, or if, we will be able to achieve or maintain profitability. Even if we are able to generate product sales, we may not become profitable. If we fail to become profitable or are unable to sustain profitability on a continuing basis, then we may be unable to continue our operations at planned levels and be forced to reduce or terminate our operations.

As of March 31, 2023, we had cash and cash equivalents and short-term investments of $583.4 million. We believe that our existing cash and cash equivalents and short-term investments will enable us to fund our operating expenses and capital expenditure requirements through at least 12 months from the issuance of the consolidated financial statements included in this Annual Report on Form 10-K.

See “— Liquidity and capital resources” and “Risk factors — Risks related to our financial position and need for additional capital.”

The COVID-19 pandemic

We are continuing to monitor the global outbreak and spread of COVID-19 and, throughout the pandemic, have implemented measures designed to comply with applicable federal, state and local guidelines, as well as care for our employee's health and well-being. We will continue to examine our protocols as the pandemic and health guidance evolves. The COVID-19 pandemic continues to affect the United States and global economies and has affected and may continue to affect our operations and those of third parties on which we rely, including by causing disruptions in our raw material and anti-PD-1 supply, the manufacturing of our product candidates and our commercialization processes. In addition, timing of patient enrollment and treatment in certain of our ongoing clinical studies has been impacted by the pandemic. However, the extent of these delays is currently unknown and has and will likely continue to vary by clinical study. In addition, we may incur unforeseen costs as a result of disruptions in raw material supplies, clinical product supplies, and preclinical studies or clinical trial delays. The full extent to which the COVID-19 pandemic will directly or indirectly impact our business, results of operations and financial condition will depend on future developments that are highly uncertain and cannot be accurately predicted, including new information that may emerge concerning COVID-19, the actions taken in an effort to contain it or to potentially treat or continue to vaccinate against COVID-19 and the economic impact on local, regional, national and international markets. We continue to actively monitor this situation and the possible effects on our financial condition, liquidity, operations, suppliers, supplies, industry and workforce.

Components of our results of operations

Revenue

To date, we have not generated any revenue from product sales as we do not have any approved products and do not expect to generate any revenue from the sale of products in the near future. If our development efforts for RP1 or any other product candidates that we may develop in the future are successful and result in regulatory approval, or if we enter into collaboration or license agreements with third parties, we may generate revenue in the future from a combination of product sales or payments from those collaborations or license agreements.

Operating expenses

Research and development expenses

Research and development expenses consist primarily of costs incurred for our research activities, including our discovery efforts and the development of our product candidates, and include:

•expenses incurred under agreements with third parties, including clinical research organizations, or CROs, that conduct research, preclinical activities and clinical trials on our behalf as well as contract manufacturing organizations, or CMOs, that manufacture our raw materials and/or product candidates for use in our preclinical and clinical trials;

•salaries, benefits and other related costs, including stock-based compensation expense, for personnel engaged in research and development functions;

•costs of outside consultants engaged in research and development functions, including their fees, stock-based compensation and related travel expenses;

•the costs of laboratory supplies and acquiring, developing and manufacturing preclinical study and clinical trial materials;

61

TABLE OF CONTENTS

•costs related to compliance with regulatory requirements in connection with the development of our product candidates; and

•facility-related expenses, which include direct depreciation costs and allocated expenses for rent and maintenance of facilities and other operating costs.

We expense research and development costs as incurred. We recognize external development costs based on an evaluation of the progress to completion of specific tasks using information provided to us by our service providers. Payments for these activities are based on the terms of the individual agreements, which may differ from the pattern of costs incurred, and are reflected in our consolidated financial statements as prepaid or accrued research and development expenses.

Our direct external research and development expenses are tracked on a program-by-program basis and consist of costs, such as fees paid to consultants, contractors, CMOs, and CROs in connection with our preclinical and clinical development activities. We do not allocate personnel costs, costs associated with our discovery efforts, laboratory supplies or other indirect costs, to specific product development programs because these costs are deployed across multiple product development programs and, as such, are not separately classified. Non-employee costs associated with our manufacturing facility including depreciation, amortization and facility costs are appropriately allocated to development programs based on the percentage of time spent per program.

Research and development activities are central to our business model. Product candidates in later stages of clinical development generally have higher development costs than those in earlier stages of clinical development, primarily due to the increased size and duration of later-stage clinical trials. We expect that our research and development expenses will continue to increase for the foreseeable future as we continue enrollment and initiate additional clinical trials and continue to discover and develop additional product candidates. The successful development and commercialization of our product candidates is highly uncertain. This is due to the numerous risks and uncertainties associated with product development and commercialization, including the following:

•the scope, rate of progress, expense and results of our ongoing clinical trials, as well as future clinical trials or other product candidates and other research and development activities that we may conduct;

•the number and scope of preclinical and clinical programs we decide to pursue;

•our ability to maintain our current research and development programs and to establish new ones;

•uncertainties in clinical trial design;

•the rate of enrollment in clinical trials;

•the successful completion of clinical trials with safety, tolerability, and efficacy profiles that are satisfactory to the FDA or any comparable foreign regulatory authority;

•the receipt of regulatory approvals from applicable regulatory authorities;

•our success in operating our manufacturing facility, or securing manufacturing supply through relationships with third parties;

•our ability to obtain and maintain patents, trade secret protection, and regulatory exclusivity, both in the United States and internationally;

•our ability to maintain, expand and protect our rights in our intellectual property portfolio;

•the commercialization of our product candidates, if and when approved;

•the acceptance of our product candidates, if approved, by patients, the medical community, and third-party payors;

•our ability to successfully develop our product candidates for use in combination with third-party products or product candidates;

•negative developments in the field of immuno-oncology;

•competition with other products; and

•significant and changing government regulation and regulatory guidance.

A change in the outcome of any of these variables with respect to the development of a product candidate could mean a significant change in the costs and timing associated with the development of that product candidate. For example, if the FDA or another regulatory authority were to require us to conduct clinical trials beyond those that we anticipate will be required for the completion of clinical development of a product candidate, or if we experience significant trial delays due to patient

62

TABLE OF CONTENTS

enrollment or other reasons, we could be required to expend significant additional financial resources and time on the completion of clinical development. We may never succeed in obtaining regulatory approval for any of our product candidates.

Selling, general and administrative expenses

Selling, general and administrative expenses consist primarily of salaries and other related costs, including stock-based compensation, for personnel in our executive, finance, corporate, commercial, and business development and administrative functions. Selling, general and administrative expenses also include professional fees for legal, patent, accounting, auditing, tax and consulting services, pre-commercial planning, marketing and strategic planning, business development, travel expenses, and facility-related expenses, which include direct depreciation costs and allocated expenses for rent and maintenance of facilities and other operating costs.

We expect that our selling, general and administrative expenses will continue to increase in the future as we increase our selling, general and administrative headcount to support our continued research and development and pre-launch activities to prepare for potential commercialization of our product candidates. We also expect to continue to incur increased expenses, including accounting, audit, legal, regulatory and tax-related services associated with maintaining compliance with exchange listing and SEC requirements; director and officer insurance costs; and investor and public relations costs.

Other income (expense), net

Research and development incentives

Research and development incentives consists of reimbursements of research and development expenditures. We participate, through our subsidiary in the United Kingdom, in the research and development program provided by the United Kingdom tax relief program, such that a percentage of up to 14.5% of our qualifying research and development expenditures are reimbursed by the United Kingdom government, and such incentives are reflected as other income.

Investment income

Investment income consists of income earned on our cash and cash equivalents and short-term investments.

Interest expense on finance lease liability

Interest expense on finance lease liability consists of amortization of finance charges under our financing lease.

Interest expense on debt obligations

Interest expense on debt obligations consists of the amortization of debt discount and cash paid for interest under the Hercules Loan Agreement.

Other income (expense), net

Other income (expense), net consists primarily of realized and unrealized foreign currency transaction gains and losses.

Income taxes

During the year ended March 31, 2023, the Company recorded an income tax provision of $0.3 million related to U.S. current taxes primarily due to the transfer pricing arrangement between the U.S. and the U.K., as well as unfavorable adjustments related to stock compensation, resulting in U.S. taxable income reduced by certain prior year available net operating losses.

During the year ended March 31, 2022, the Company recorded no income tax benefit for the net operating losses incurred due to the uncertainty of the realization of such losses.

Results of operations

Comparison of the years ended March 31, 2023 and 2022

The following table summarizes our results of operations for the years ended March 31, 2023 and 2022:

63

TABLE OF CONTENTS

Research and development expenses

Research and development expenses for the year ended March 31, 2023 were $126.5 million, compared to $79.5 million for the year ended March 31, 2022. The following table summarizes our research and development expenses for the years ended March 31, 2023 and 2022:

The change in our direct research and development expenses between our product candidates is primarily associated with technology transfer from RP2 to RP3, process development, qualification and comparability of our in-house manufactured materials compared to our third-party manufactured materials in readiness for utilizing our product candidates made at our in-house manufacturing facility in our clinical development programs and preparation for potential commercial manufacture, if approved.

The increase in RP1 is primarily the result of an increase in our number of clinical trial sites and patient enrollment as compared to the prior year, and a reduction of $5.7 million of costs sharing in the CERPASS trial from Regeneron during the current period as discussed in Note 12 to the consolidated financial statements appearing elsewhere in this Annual Report. During the second half of the year, manufacturing shifted focus to validation batches for RP1, which is the driver of the change in program costs year over year.

The increase of $21.8 million in our unallocated expenses was due primarily to a $16.1 million increase in personnel-related costs, including a $14.6 million increase in payroll and fringe benefits and a stock-based compensation increase of $1.5 million. The increase in personnel-related costs largely reflected the hiring of additional personnel in our research and development functions as we expand the development plan in multiple indications. Personnel related costs for the years ended March 31, 2023 and 2022 included stock-based compensation expense of $10.1 million and $8.6 million, respectively.

64

TABLE OF CONTENTS

Additionally, the increase in other expenses is primarily driven by an increase of $2.6 million in consulting costs across our platform and a $0.9 million of increased costs related to our manufacturing facility and related lease costs.

Selling, general and administrative expenses

Selling, general and administrative expenses were $50.6 million for the year ended March 31, 2023, compared to $38.8 million for the year ended March 31, 2022. The increase of $11.8 million is primarily the result of an increase of $5.9 million in personnel related costs, including a stock-based compensation increase of $2.4 million, an increase of $3.5 million in payroll and fringe benefits. The increase in personnel related costs was driven by the continued hiring of additional personnel in our selling, general and administrative functions, focusing on additional pre-launch planning and initial build of the Company's commercial infrastructure, which accounts for approximately $1.2 million of the increase compared to prior year. Additionally, there is an increase of $4.9 million in other variable costs which is driven by external spend increases for sales and marketing programs, advertising and market research.

Total other income (expense), net

Other income for the year ended March 31, 2023 was $3.1 million compared to $0.3 million for the year ended March 31, 2022. The net change of $2.8 million is primarily attributable to an increase of $9.6 million in investment income in the current year as compared to the prior year. This increase was somewhat offset by a $4.6 million increase in expense due to the changes in foreign exchange rates of the Great British Pound to United States Dollar, as well as an increase in expense of $2.0 million as a result of interest expense on debt obligations.

Income tax provision

Income tax provision for the year ended March 31, 2023 was $0.3 million compared to $0.0 million for the year ended March 31, 2022. The income tax provision for the current year is attributable to U.S. current taxes primarily due to the transfer pricing arrangement between the U.S. and the U.K., as well as unfavorable adjustments related to stock compensation, resulting in U.S. taxable income reduced by certain prior year available net operating losses.

Liquidity and capital resources

Since our inception, we have not generated any revenue from product sales and have incurred significant operating losses and negative cash flows from our operations. We have not yet commercialized any of our product candidates, which are in various phases of preclinical and clinical development, and we do not expect to generate revenue from sales of any products for the foreseeable future, if at all.

Sources of liquidity

To date, we have financed our operations primarily with proceeds from the sale of equity securities and, to a lesser extent, proceeds from borrowing under a secured loan facility. Through March 31, 2023, we had received net proceeds of $935.9 million through the sale of equity securities, as well as net $27.8 million from our incurrence of debt under the Hercules Loan Agreement. As of March 31, 2023, we had cash and cash equivalents and short-term investments of $583.4 million.

Cash flows

The following table summarizes our cash flows for each of the periods presented:

Operating activities

65

TABLE OF CONTENTS

During the year ended March 31, 2023, net cash used in operating activities was $128.1 million, primarily resulting from our net loss of $174.3 million, partially offset by non-cash charges of $31.1 million, consisting primarily of stock-based compensation expense of $28.1 million, and an increase in cash of $15.1 million related to changes in our operating assets and liabilities. Changes in our operating assets and liabilities for the year ended March 31, 2023 consisted primarily of a $11.4 million increase in accrued expenses and other current liabilities, a net $2.4 million change in operating and financing right-of-use assets and lease liabilities, and a $2.0 million increase in accounts payable.

During the year ended March 31, 2022, net cash used in operating activities was $82.2 million, primarily resulting from our net loss of $118.0 million, partially offset by non-cash charges of $28.6 million, consisting of stock-based compensation expense of $24.3 million and $4.4 million of expense related to depreciation and amortization and net amortization of premiums and discounts on short-term investments, and an increase in cash of $7.2 million related to changes in our operating assets and liabilities. Changes in our operating assets and liabilities for the year ended March 31, 2022 consisted primarily of a $4.7 million increase in accrued expenses and other current liabilities, a net $2.5 million change in operating and financing right-of-use assets and lease liabilities, a $1.1 million increase in accounts payable and a $0.8 million increase in prepaid expenses and other current assets, as well as a $0.2 million increase in research and development incentives receivable from the United Kingdom government due to the timing and amount of qualifying expenditures.

Investing activities

During the year ended March 31, 2023, net cash used in investing activities was $142.5 million, consisting of $583.4 million in purchases of available for sale securities and $2.3 million in purchases of property, plant and equipment, offset by $443.2 million in proceeds from sales and maturities of short-term investments.

During the year ended March 31, 2022, net cash used in investing activities was $1.8 million, consisting of $255.7 million in purchases of available for sale securities and $2.3 million in purchases of property, plant and equipment, offset by $256.3 million in proceeds from sales and maturities of short-term investments.

Financing Activities

During the year ended March 31, 2023, net cash provided by financing activities was $311.3 million, consisting primarily of $149.9 million in proceeds from the issuance of common stock, $92.8 million from the issuance of pre-funded warrants to purchase common stock, $37.4 million from the issuance of common stock through sales under our at-the-market facilities, $28.2 million in proceeds from the incurrence of debt under the Hercules Loan Agreement, as well as approximately $3.4 million in proceeds from the exercise of stock options.

During the year ended March 31, 2022, net cash provided by financing activities was $6.6 million, consisting primarily of $6.9 million in proceeds from the exercise of stock options.

Funding requirements

Our plan of operation is to continue implementing our business strategy, continue research and development of our RPx platform, and continue to expand our research pipeline and our internal research and development capabilities. We expect our expenses to increase substantially in connection with our ongoing activities, particularly as we advance the preclinical activities and clinical trials of our product candidates and if and as we:

•conduct our current and future clinical trials with RP1, RP2 and RP3;

•further preclinical development of our RPx platform;

•operate, qualify and maintain our in-house manufacturing facility and qualify and maintain our product candidates made therein for use in our clinical trials;

•seek to identify and develop additional product candidates;

•seek marketing approvals for any of our product candidates that successfully complete clinical trials, if any;

•establish a sales, marketing and distribution infrastructure to commercialize any products for which we may obtain marketing approval;

•until our planned manufacturing facility is fully validated, continued limited manufacturing by third parties for clinical development;

•maintain, expand and protect our intellectual property portfolio;

•acquire or in-license other drugs, technologies or third-party intellectual property; and

66

TABLE OF CONTENTS

•add operational, financial and management information systems and personnel, including personnel to support our research and development programs, any future commercialization efforts and operations as a public company.

As of March 31, 2023, we had cash and cash equivalents and short-term investments of $583.4 million. Based on our current operating plan, we believe that our existing cash, cash equivalents and short-term investments as of March 31, 2023, will enable us to fund operations into the second half of calendar year 2025.

Because of the numerous risks and uncertainties associated with the development of RP1 and other product candidates and programs, and because the extent to which we may enter into collaborations with third parties for development of our product candidates is unknown, we are unable to estimate the timing and amounts of increased capital outlays and operating expenses associated with completing the research and development of our product candidates. Our future capital requirements will depend on many factors, including those described in this section and above under “— Operating expenses — Research and development expenses.”

Developing novel biopharmaceutical products, including conducting preclinical studies and clinical trials, is a time-consuming, expensive and uncertain process that takes years to complete, and we may never generate the necessary data or results required to obtain marketing approval for any product candidates or generate revenue from the sale of any products for which we may obtain marketing approval. In addition, our product candidates, if approved, may not achieve commercial success. Our commercial revenues, if any, will be derived from sales of therapies that we do not expect to be commercially available for many years, if ever. Accordingly, we will need to obtain substantial additional funds to achieve our business objectives.

Adequate additional funds may not be available to us on acceptable terms, or at all. We do not currently have any committed external source of funds. To the extent that we raise additional capital through the sale of our equity or convertible debt securities, our shareholders’ interest may be diluted, and the terms of these securities may include liquidation or other preferences and anti-dilution protections that could adversely affect the rights of our common stockholder. Additional debt or preferred equity financing, if available, may involve agreements that include restrictive covenants that may limit our ability to take specific actions, such as incurring debt, adversely impact our ability to conduct our business, and may require the issuance of warrants, which could potentially dilute your ownership interest.

If we raise additional funds through collaborations, strategic alliances or licensing arrangements with third parties, we may have to relinquish valuable rights to our technology, future revenue streams, research programs, or product candidates or grant licenses on terms that may not be favorable to us. If we are unable to raise additional funds through equity or debt financings or collaborations, strategic alliances or licensing arrangements with third parties when needed, we may be required to delay, limit, reduce and/or terminate our product development programs or any future commercialization efforts or grant rights to develop and market product candidates that we would otherwise prefer to develop and market ourselves.

Contractual obligations and commitments

We have entered into arrangements that contractually obligate us to make payments that will affect our liquidity and cash flows in future periods. Our contractual obligations include those related to our operating and financing leases, long-term debt, as well as costs associated with contracts entered into in the normal course of business with CROs, CMOs and other third parties for clinical trials and preclinical research studies and testing.

Lease Commitments

As of March 31, 2023, the aggregate amount of future lease payments is approximately $56.6 million, with $3.8 million due within one year. For additional information on our leases and timing of future payments, see Note 13 Commitments and contingencies, of the "notes to Consolidated Financial Statements" contained in Part II, Item 8 of this Annual Report on Form 10-K.

Loan Agreement

Our commitments due for our term loan under our arrangement with Hercules include principal payments of $30.0 million as of March 31, 2023. Borrowings under the term loan agreement are repayable in monthly interest-only payments through September 2026, and the agreement has a maturity date of October 2027. Our remaining commitments, based on our current draws, are due through October 2027, and include principal and interest payments of $43.8 million, and an additional fee upon

67

TABLE OF CONTENTS

maturity of the loan of $1.5 million. See Note 7, Long term debt, of the "notes to Consolidated Financial Statements" contained in Part II, Item 8 of this Annual Report on Form 10-K for further discussion of the Hercules term loan.

Other Obligations

Manufacturing and research commitments include agreements that are enforceable and legally binding on us and that specify all significant terms, including fixed or minimum quantities to be purchased; fixed, minimum or variable price provisions; and the approximate timing of the transaction. As of March 31, 2023, the aggregate amount of non-cancelable purchase obligations related to such manufacturing commitments are approximately $1.0 million and all of this balance is due within one year.

Collaborations

BMS

In February 2018, we entered into a Clinical Trial Collaboration and Supply Agreement with Bristol-Myers Squibb Company, or BMS. Pursuant to the agreement, BMS is providing to us, at no cost, nivolumab, its anti-PD-1 therapy, for use in combination with RP1 in our ongoing Phase 1/2 clinical trial. Under the agreement, we will sponsor, fund and conduct the clinical trial in accordance with an agreed-upon protocol. BMS granted us a non-exclusive, non-transferrable, royalty-free license (with a right to sublicense) under its intellectual property to use nivolumab in the clinical trial and has agreed to supply nivolumab, at no cost to us, for use in the clinical trial. Both parties will own the study data produced in the clinical trial, other than study data related solely to nivolumab, which will belong solely to BMS, or study data related solely to RP1, which will belong solely to us. In January 2020, this agreement was expanded to cover an additional cohort of 125 patients with anti-PD-1 failed melanoma.

Unless earlier terminated, the agreement will remain in effect until (i) the completion of the clinical trial, (ii) all related clinical trial data have been delivered to both parties and (iii) the completion of any statistical analyses and bioanalyses contemplated by the clinical trial protocol or any analysis otherwise agreed upon by the parties. The agreement may be terminated by either party (x) in the event of an uncured material breach by the other party, (y) in the event the other party is insolvent or in bankruptcy proceedings or (z) for safety reasons. Upon termination, the licenses granted to us to use nivolumab in the clinical trial will terminate. The agreement contains representations, warranties, undertakings and indemnities customary for a transaction of this nature.

In April 2019, we entered into a separate agreement with BMS on terms similar to the terms set forth in the agreement described above, pursuant to which BMS will provide, at no cost to us, nivolumab for use in our Phase 1 clinical trial of RP2 in combination with nivolumab.

Regeneron

In May 2018, we entered into a Master Clinical Trial Collaboration and Supply Agreement with Regeneron. Pursuant to the agreement we agreed to undertake one or more clinical trials with Regeneron for the administration of our product candidates in combination with cemiplimab, an anti-PD-1 therapy developed by Regeneron, across multiple solid tumor types, the first of which is our ongoing Phase 2 clinical trial testing RP1 in combination with cemiplimab versus cemiplimab alone in patients with CSCC. Each clinical trial will be conducted pursuant to an agreed study plan which, among other things, will identify the name of the sponsor and which party will manage the particular study, and include the protocol, the budget and a schedule of clinical obligations. The first study plan related to the Phase 2 clinical trial in CSCC has been agreed.

Pursuant to the terms of the agreement, each party granted the other party a non-exclusive license of their respective intellectual property and agreed to contribute the necessary resources needed to fulfill their respective obligations, in each case, under the terms of agreed study plans. Development costs of an agreed study plan will be split equally. In July 2022, Regeneron informed the Company that the costs of the study have reached the initial budget for the initial study plan of June 2018 and that Regeneron's reimbursement of CERPASS study costs to the Company have completed in the period ending June 30, 2022 in relation to the initial study budget. As a result of this notice from, and the ongoing communications with, Regeneron, we have not recorded any cost-sharing reimbursements from Regeneron in prepaid expenses and other current assets in the consolidated balance sheet or as an offset to research and development expense within the consolidated statement of operations since Regeneron informed us that Regeneron’s reimbursement of CERPASS study costs have completed. The Company does not expect any further reimbursements from Regeneron related to the initial study plan of June 2018. The agreement contains representations, warranties, undertakings and indemnities customary for a transaction of this nature. The agreement also contains certain time-based covenants that restrict us from entering into a third-party arrangement with respect to the use of our product candidates in combination with an anti-PD-1 therapy and that restrict Regeneron from entering into a third-party arrangement with respect to the use of cemiplimab in combination with an HSV-1 virus, in each case, for the treatment of a

68

TABLE OF CONTENTS

tumor type that is the subject of a clinical trial to which the covenants apply. Unless otherwise mutually agreed in a future study plan, these covenants are only applicable to our ongoing Phase 2 clinical trial in CSCC.

The agreement may be terminated by either party if (i) there is no active study plan for which a final study report has not been completed and the parties have not entered into a study plan for an additional clinical trial within a period of time after the delivery of the most recent final study report or (ii) in the event of a material breach.

Roche

In December 2022, we entered into a Master Clinical Trial Collaboration and Supply Agreement with Roche in relation to our RP2 and RP3 programs in colorectal cancer, or CRC, and hepatocellular carcinoma, or HCC. Under the agreement, the companies will collaborate in 30 patient cohort signal finding studies in third-line, or 3L, CRC and in first- and second-line, or 1L and 2L, respectively, HCC. Under the terms of the agreement, the companies will share costs and Roche will supply its currently approved drugs, atezolizumab and bevacizumab for 2L HCC and 3L CRC combined with RP3. Roche will also supply atezolizumab and bevacizumab for 1L HCC combined with RP3, and for 3L CRC combined with RP2. We have retained the responsibility of operating the clinical trials as well as retaining all the rights to the development and commercialization of our product candidates. The agreement may be terminated by either party upon sixty (60) days prior written notice to the other party.

Critical accounting policies and estimates

Our management’s discussion and analysis of financial condition and results of operations is based on our consolidated financial statements, which have been prepared in accordance with generally accepted accounting principles in the United States. The preparation of our consolidated financial statements and related disclosures requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities, costs and expenses and the disclosure of contingent assets and liabilities in our consolidated financial statements. We base our estimates on historical experience, known trends and events and various other factors that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. We evaluate our estimates and assumptions on an ongoing basis. Our actual results may differ from these estimates under different assumptions or conditions.

While our significant accounting policies are described in greater detail in Note 2 to our consolidated financial statements appearing elsewhere in this Annual Report on Form 10-K, we believe that the following accounting policies are those most critical to the judgments and estimates used in the preparation of our consolidated financial statements.

Accrued research and development expenses

As part of the process of preparing our consolidated financial statements, we are required to estimate our accrued research and development expenses. This process involves reviewing open contracts and purchase orders, communicating with our personnel to identify services that have been performed on our behalf and estimating the level of service performed and the associated cost incurred for the service when we have not yet been invoiced or otherwise notified of actual costs. The majority of our service providers invoice us in arrears for services performed, on a pre-determined schedule or when contractual milestones are met; however, some require advanced payments. We make estimates of our accrued expenses as of each balance sheet date in the consolidated financial statements based on facts and circumstances known to us at that time. Examples of estimated accrued research and development expenses include fees paid to:

•CROs in connection with performing research activities and conducting preclinical studies and clinical trials on our behalf;

•CMOs in connection with the production of preclinical and clinical trial materials;

•investigative sites or other service providers in connection with clinical trials;

•vendors in connection with preclinical and clinical development activities; and

•vendors related to product manufacturing and development and distribution of preclinical and clinical supplies.

We base our expenses related to preclinical studies and clinical trials on our estimates of the services received and efforts expended pursuant to quotes and contracts with multiple CMOs and CROs that supply, conduct and manage preclinical studies and clinical trials on our behalf. The financial terms of these agreements are subject to negotiation, vary from contract to contract and may result in uneven payment flows. There may be instances in which payments made to our vendors will exceed the level of services provided and result in a prepayment of the expense. Payments under some of these contracts depend on factors such as the successful enrollment of patients and the completion of clinical trial milestones. In accruing service fees, we

69

TABLE OF CONTENTS

estimate the time period over which services will be performed and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from the estimate, we adjust the accrual or the amount of prepaid expenses accordingly. Although we do not expect our estimates to be materially different from amounts actually incurred, our understanding of the status and timing of services performed relative to the actual status and timing of services performed and/or timing of receiving invoices for actual services performed may vary and may result in reporting amounts that are too high or too low in any particular period. To date, there have not been any material adjustments to our prior estimates of accrued research and development expenses.

Stock-based compensation

We issue stock-based awards to employees, directors, consultants and non-employees in the form of stock options and restricted stock units. We measure such stock-based awards in accordance with ASC 718, Compensation — Stock Compensation, which requires all stock-based awards to be recognized in the consolidated statements of operations and comprehensive loss based on their fair value on the date of the grant and the related compensation expense for those awards is recognized over the requisite service period, which is generally the vesting period of the respective award. We have, to date, only issued stock-based awards with service-based vesting conditions and record the expense for these awards using the straight-line method. The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes option-pricing model, which requires inputs based on certain subjective assumptions, including the expected stock price volatility, the expected term of the option, the risk-free interest rate for a period that approximates the expected term of the option, and our expected dividend yield. See Note 10 of the "Notes to Consolidated Financial Statements" contained in Part II, Item 8 of this Annual Report on Form 10-K for more information. Forfeitures are accounted for as they occur. The fair value of each stock-based award is estimated on the date of grant based on the fair value of our common stock on that same date.

We classify stock-based compensation expense in our consolidated statements of operations in the same manner in which the award recipient’s payroll costs are classified or in which the award recipient’s service payments are classified.

Recently issued accounting pronouncements

Refer to Note 2, summary of significant accounting policies of the “Notes to Consolidated Financial Statements” contained in Part II, Item 8 of this Annual Report on Form 10-K for a description of recent accounting pronouncements that are applicable to our business and may potentially have an impact on our financial position and results of operations.

Emerging growth company status

As an “emerging growth company,” the Jumpstart Our Business Startups Act of 2012 permits us to take advantage of an extended transition period to comply with new or revised accounting standards applicable to public companies until those standards would otherwise apply to private companies. We have irrevocably elected to “opt out” of this provision and, as a result, we will comply with new or revised accounting standards when they are required to be adopted by public companies that are not emerging growth companies.

Item 7.    Management’s discussion and analysis of financial condition and results of operations

You should read the following discussion and analysis of our financial condition and results of operations in conjunction with our consolidated financial statements and related notes and other financial information included elsewhere in this Annual Report on Form 10-K. In addition to historical information, some of the statements contained in this discussion and analysis or set forth elsewhere in this Annual Report on Form 10-K, including information with respect to our plans and strategy for our business, constitute forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act. We have based these forward-looking statements on our current expectations and projections about future events. The following information and any forward-looking statements should be considered in light of factors discussed elsewhere in this Annual Report on Form 10-K, particularly including those risks identified in Part I, Item 1A “Risk factors” and our other filings with the Securities Exchange Commission, or SEC.

We caution you that forward-looking statements are not guarantees of future performance and that our actual results of operations, financial condition and liquidity, and the development of the industry in which we operate may differ materially from the forward-looking statements contained in this Annual Report on Form 10-K. Statements made herein are as of the date of the filing of this Annual Report on Form 10-K with the SEC and should not be relied upon as of any subsequent date. Even if our results of operations, financial condition and liquidity, and the development of the industry in which we operate are consistent with the forward-looking statements contained in this Annual Report on Form 10-K, they may not be predictive of

55

TABLE OF CONTENTS

results or developments in future periods. We disclaim any obligation, except as specifically required by law and the rules of the SEC, to publicly update or revise any such statements to reflect any change in our expectations or in events, conditions or circumstances on which any such statements may be based or that may affect the likelihood that actual results will differ from those set forth in the forward-looking statements.

Overview

We are a clinical-stage biotechnology company committed to applying our leading expertise in the field of oncolytic immunotherapy to transform the lives of cancer patients through our novel tumor-directed oncolytic immunotherapies. Our proprietary tumor-directed oncolytic immunotherapy product candidates are designed and intended to maximally activate the immune system against cancer.

Oncolytic immunotherapy is an emerging drug class, which we intend to establish as the second cornerstone of immune-based cancer treatments, alongside checkpoint blockade. Oncolytic immunotherapy exploits the ability of certain viruses to selectively replicate in and directly kill tumors, as well as induce a potent, patient-specific, anti-tumor immune response. Our product candidates incorporate multiple mechanisms of action into a practical “off-the-shelf” approach that is intended to maximize the immune response against a patient’s cancer and to offer significant advantages over other approaches of inducing anti-tumor immunity, including personalized vaccine approaches. We believe that the bundling of multiple approaches for the treatment of cancer into single therapies will simplify the development path of our product candidates, while also improving patient outcomes at a lower cost to the healthcare system than the use of multiple different drugs.

Financial

Since our inception, we have devoted substantially all of our resources to developing our proprietary RPx platform, building our intellectual property portfolio, conducting research and development of our product candidates, business planning, raising capital and providing selling, general and administrative support for our operations. To date, we have financed our operations primarily with proceeds from the sale of equity securities and to a lesser extent the proceeds from the issuance of debt securities. We do not have any products approved for sale and have not generated any revenue from product sales.

Since commencement of our initial public offering, or IPO, on July 20, 2018, we have raised an aggregate of approximately $569.0 million in net proceeds to fund our operations, of which $101.2 million was from our IPO, $463.4 million was from three separate follow-on offerings, or the Public Offerings, that we closed in November 2019, June 2020 and October 2020, respectively, and $4.4 million was from at-the-market offerings. We sold 7,407,936 shares of common stock in our IPO, an aggregate of 13,619,822 shares of our common stock and pre-funded warrants to purchase 5,284,238 shares of our common stock in the Public Offerings, and 287,559 shares of common stock through our at-the-market facility.

Funds affiliated with two separate institutional investors hold all of our outstanding pre-funded warrants. Other than as set forth in Notes 8, 9 and 10 of the "Notes to Consolidated Financial Statements" contained in Part II, Item 8 of this Annual Report on From 10-K, the shares of our common stock into which our outstanding pre-funded warrants are exercisable are not included in the number of issued and outstanding shares of our common stock set forth in this Annual Report on Form 10-K.

In addition, on August 8, 2019, we entered into a Loan and Security Agreement with Hercules Capital, Inc., or Hercules, which we refer to as the Hercules Loan Agreement, pursuant to which we borrowed $10.0 million under a secured term loan facility in the amount of $30.0 million. The Hercules Loan Agreement was subsequently amended on June 1, 2020, in order to, among other things, increase the secured term loan facility from $30.0 million to $40.0 million. On December 15, 2020, we paid a total of $10.8 million, representing the outstanding principal, accrued and unpaid interest, fees, costs and expenses due and owing under the Hercules Loan Agreement and related loan documents, in repayment of all of our outstanding obligations thereunder, and thereby terminated the Hercules Loan Agreement and the related loan documents.

Since our inception, we have incurred significant operating losses. Our ability to generate product revenue sufficient to achieve profitability will depend on the successful development and eventual commercialization of one or more of our product candidates. Our net losses were $118.0 million and $80.9 million for the years ended March 31, 2022 and 2021, respectively. As of March 31, 2022, we had an accumulated deficit of $311.2 million. These losses have resulted primarily from costs incurred in connection with research and development activities and selling, general and administrative costs associated with our operations. We expect to continue to incur significant expenses and increasing operating losses for at least the next several years.

We anticipate that our expenses and capital requirements will increase substantially in connection with our ongoing activities, particularly as we advance the clinical trials, development and pre-commercial activities related to our RPx platform product candidates, and if and as we:

56

TABLE OF CONTENTS

•conduct our current and future clinical trials with RP1, RP2 and RP3;

•further preclinical development of our RPx platform;

•qualify, operate or maintain our own in-house manufacturing facility;

•seek to identify and develop additional product candidates;

•seek marketing approvals for any of our product candidates that successfully complete clinical trials, if any;

•establish a sales, marketing and distribution infrastructure to commercialize any products for which we may obtain marketing approval;

•until our manufacturing facility is fully validated, continued limited manufacturing by third parties for clinical development;

•maintain, expand and protect our intellectual property portfolio;

•hire and retain additional clinical, quality control, scientific and selling, general and administration personnel;

•acquire or in-license other drugs and technologies; and

•add operational, financial and management information systems and personnel, including personnel to support our research and development programs, any future commercialization efforts and operations as a public company.

We will not generate revenue from product sales unless and until we successfully complete clinical development and obtain regulatory approval for RP1 or our other product candidates. If we obtain regulatory approval for any of our product candidates and do not enter into a commercialization partnership in any jurisdiction, we expect to incur significant expenses related to developing our internal commercialization capability to support product sales, marketing, and distribution.

As a result, we will need additional funding to support our continuing operations and pursue our growth strategy. Until such time as we can generate significant revenue from product sales, if ever, we expect to finance our operations through a combination of equity offerings, debt financings, lines of credit, collaborations, strategic alliances, and marketing, distribution, or licensing arrangements. We may be unable to raise additional funds or enter into such other agreements or arrangements when needed on favorable terms, or at all. If we fail to raise capital or enter into such agreements as, and when, needed, we may have to significantly delay, scale back, or discontinue the development and commercialization of one or more of our product candidates.

Because of the numerous risks and uncertainties associated with pharmaceutical product development, we are unable to accurately predict the timing or amount of increased expenses or when, or if, we will be able to achieve or maintain profitability. Even if we are able to generate product sales, we may not become profitable. If we fail to become profitable or are unable to sustain profitability on a continuing basis, then we may be unable to continue our operations at planned levels and be forced to reduce or terminate our operations.

As of March 31, 2022, we had cash and cash equivalents and short-term investments of $395.7 million. We believe that our existing cash and cash equivalents and short-term investments will enable us to fund our operating expenses and capital expenditure requirements through at least 12 months from the issuance of the consolidated financial statements included in this Annual Report on Form 10-K.

See “— Liquidity and capital resources” and “Risk factors — Risks related to our financial position and need for additional capital.”

The COVID-19 pandemic

We are continuing to monitor the global outbreak and spread of COVID-19 and, throughout the pandemic, have implemented measures designed to comply with applicable federal, state and local guidelines, as well as care for our employee's health and well-being. We will continue to examine our protocols as the pandemic and health guidance evolves. The COVID-19 pandemic continues to affect the United States and global economies and has affected and may continue to affect our operations and those of third parties on which we rely, including by causing disruptions in our raw material and anti-PD-1 supply, the manufacturing of our product candidates and our commercialization processes. In addition, timing of patient enrollment and treatment in certain of our ongoing clinical studies has been impacted by the pandemic. However, the extent of these delays is currently unknown and has and will likely continue to vary by clinical study. In addition, we may incur unforeseen costs as a result of disruptions in raw material supplies, clinical product supplies, and preclinical studies or clinical trial delays. The full extent to which the COVID-19 pandemic will directly or indirectly impact our business, results of operations and financial condition will depend on future developments that are highly uncertain and cannot be accurately predicted, including new

57

TABLE OF CONTENTS

information that may emerge concerning COVID-19, the actions taken in an effort to contain it or to potentially treat or continue to vaccinate against COVID-19 and the economic impact on local, regional, national and international markets. We continue to actively monitor this situation and the possible effects on our financial condition, liquidity, operations, suppliers, supplies, industry and workforce. For additional information, see “Risk Factors — Our financial condition and results of operations could be adversely affected by the coronavirus disease-2019, or COVID-19, outbreak.” in Part I, Item 1A of this Annual Report on Form 10-K.

Components of our results of operations

Revenue

To date, we have not generated any revenue from product sales as we do not have any approved products and do not expect to generate any revenue from the sale of products in the near future. If our development efforts for RP1 or any other product candidates that we may develop in the future are successful and result in regulatory approval, or if we enter into collaboration or license agreements with third parties, we may generate revenue in the future from a combination of product sales or payments from those collaborations or license agreements.

Operating expenses

Research and development expenses

Research and development expenses consist primarily of costs incurred for our research activities, including our discovery efforts and the development of our product candidates, and include:

•expenses incurred under agreements with third parties, including clinical research organizations, or CROs, that conduct research, preclinical activities and clinical trials on our behalf as well as contract manufacturing organizations, or CMOs, that manufacture our product candidates for use in our preclinical and clinical trials;

•salaries, benefits and other related costs, including stock-based compensation expense, for personnel engaged in research and development functions;

•costs of outside consultants engaged in research and development functions, including their fees, stock-based compensation and related travel expenses;

•the costs of laboratory supplies and acquiring, developing and manufacturing preclinical study and clinical trial materials;

•costs related to compliance with regulatory requirements in connection with the development of our product candidates; and

•facility-related expenses, which include direct depreciation costs and allocated expenses for rent and maintenance of facilities and other operating costs.

These costs will be partially offset by our agreement with Regeneron related to our CERPASS trial.

We expense research and development costs as incurred. We recognize external development costs based on an evaluation of the progress to completion of specific tasks using information provided to us by our service providers. Payments for these activities are based on the terms of the individual agreements, which may differ from the pattern of costs incurred, and are reflected in our consolidated financial statements as prepaid or accrued research and development expenses.

Our direct external research and development expenses are tracked on a program-by-program basis and consist of costs, such as fees paid to consultants, contractors, CMOs, and CROs in connection with our preclinical and clinical development activities. We do not allocate personnel costs, costs associated with our discovery efforts, laboratory supplies, and facilities, including depreciation or other indirect costs, to specific product development programs because these costs are deployed across multiple product development programs and, as such, are not separately classified. All non-employee costs associated with our manufacturing facility have been fully burdened to our RP1 program.

Research and development activities are central to our business model. Product candidates in later stages of clinical development generally have higher development costs than those in earlier stages of clinical development, primarily due to the increased size and duration of later-stage clinical trials. We expect that our research and development expenses will continue to increase for the foreseeable future as we continue enrollment and initiate additional clinical trials and continue to discover and develop additional product candidates. The successful development and commercialization of our product candidates is highly

58

TABLE OF CONTENTS

uncertain. This is due to the numerous risks and uncertainties associated with product development and commercialization, including the following:

•the scope, rate of progress, expense and results of our ongoing clinical trials, as well as future clinical trials or other product candidates and other research and development activities that we may conduct;

•the number and scope of preclinical and clinical programs we decide to pursue;

•our ability to maintain our current research and development programs and to establish new ones;

•uncertainties in clinical trial design;

•the rate of enrollment in clinical trials;

•the successful completion of clinical trials with safety, tolerability, and efficacy profiles that are satisfactory to the FDA or any comparable foreign regulatory authority;

•the receipt of regulatory approvals from applicable regulatory authorities;

•our success in operating our manufacturing facility, or securing manufacturing supply through relationships with third parties;

•our ability to obtain and maintain patents, trade secret protection, and regulatory exclusivity, both in the United States and internationally;

•our ability to maintain, expand and protect our rights in our intellectual property portfolio;

•the commercialization of our product candidates, if and when approved;

•the acceptance of our product candidates, if approved, by patients, the medical community, and third-party payors;

•our ability to successfully develop our product candidates for use in combination with third-party products or product candidates;

•negative developments in the field of immuno-oncology;

•competition with other products; and

•significant and changing government regulation and regulatory guidance.

A change in the outcome of any of these variables with respect to the development of a product candidate could mean a significant change in the costs and timing associated with the development of that product candidate. For example, if the FDA or another regulatory authority were to require us to conduct clinical trials beyond those that we anticipate will be required for the completion of clinical development of a product candidate, or if we experience significant trial delays due to patient enrollment or other reasons, we could be required to expend significant additional financial resources and time on the completion of clinical development. We may never succeed in obtaining regulatory approval for any of our product candidates.

Selling, general and administrative expenses

Selling, general and administrative expenses consist primarily of salaries and other related costs, including stock-based compensation, for personnel in our executive, finance, corporate, commercial, and business development and administrative functions. Selling, general and administrative expenses also include professional fees for legal, patent, accounting, auditing, tax and consulting services, pre-commercial planning, travel expenses, and facility-related expenses, which include direct depreciation costs and allocated expenses for rent and maintenance of facilities and other operating costs.

We expect that our selling, general and administrative expenses will continue to increase in the future as we increase our selling, general and administrative headcount to support our continued research and development and pre-launch activities to prepare for potential commercialization of our product candidates. We also expect to continue to incur increased expenses, including accounting, audit, legal, regulatory and tax-related services associated with maintaining compliance with exchange listing and SEC requirements; director and officer insurance costs; and investor and public relations costs.

Other income (expense), net

Research and development incentives

Research and development incentives consists of reimbursements of research and development expenditures. We participate, through our subsidiary in the United Kingdom, in the research and development program provided by the United

59

TABLE OF CONTENTS

Kingdom tax relief program, such that a percentage of up to 14.5% of our qualifying research and development expenditures are reimbursed by the United Kingdom government, and such incentives are reflected as other income.

Investment income

Investment income consists of income earned on our cash and cash equivalents and short-term investments.

Interest expense on finance lease liability

Interest expense on finance lease liability consists of amortization of finance charges under our financing lease.

Interest expense on debt obligations

Interest expense on debt obligations consists of the amortization of debt discount and cash paid for interest under the term loan facility with Hercules.

Loss on extinguishment of debt

Loss on extinguishment of debt consists of the loss from extinguishment of debt obligations under the term loan facility with Hercules.

Other income (expense), net

Other income (expense), net consists primarily of realized and unrealized foreign currency transaction gains and losses.

Income taxes

Since our inception and through March 31, 2022, we have not recorded any income tax benefits for the net losses we incurred in each jurisdiction in which we operate, as we believe, based upon the weight of available evidence, that it is more likely than not that all of our net operating loss carryforwards will not be realized.

Results of operations

Comparison of the years ended March 31, 2022 and 2021

The following table summarizes our results of operations for the years ended March 31, 2022 and 2021:

60

TABLE OF CONTENTS

Research and development expenses

Research and development expenses for the year ended March 31, 2022 were $79.5 million, compared to $56.8 million for the year ended March 31, 2021. The following table summarizes our research and development expenses for the years ended March 31, 2022 and 2021:

The change in our direct research and development expenses between our product candidates is associated with technology transfer, process development, qualification and comparability of our in-house manufactured materials compared to our third-party manufactured materials in readiness for utilizing our product candidates made at our in-house manufacturing facility in our clinical development programs and preparation for potential commercial manufacture, if approved. Manufacturing continued to focus on RP2 and RP3 technology transfers and process development during the fourth quarter, as well as continued readiness for clinical trial development of these product candidates made at our in-house facility.

The increase of $21.8 million in our unallocated expenses was due primarily to a $14.6 million increase in personnel-related costs, including a $11.6 million increase in payroll and fringe benefits and a stock-based compensation increase of $2.8 million. The increase in personnel-related costs largely reflected the hiring of additional personnel in our research and development functions as we expand the development plan in multiple indications. Personnel related costs for the years ended March 31, 2022 and 2021 included stock-based compensation expense of $8.6 million and $5.7 million, respectively. Additionally, the increase in other expenses is largely driven by $3.2 million of increased costs related to our manufacturing facility and related lease costs, as well as an increase of $1.9 million in research costs and an increase of $0.9 million in lab supplies.

Selling, general and administrative expenses

Selling, general and administrative expenses were $38.8 million for the year ended March 31, 2022, compared to $23.2 million for the year ended March 31, 2021. The increase of $15.6 million is primarily the result of an increase of $13.1 million in personnel related costs, including a stock-based compensation increase of $9.6 million, an increase of $3.2 million in payroll and fringe benefits and a $0.3 million increase in travel and entertainment. The increase in personnel related costs was driven by the continued hiring of additional personnel in our selling, general and administrative functions, including the addition of commercial personnel associated with pre-launch commercial planning and initial build of the Company's commercial infrastructure, which accounts for approximately $1.7 million of the increase compared to prior year, as we expand our operations.

Total other income (expense), net

Other income (expense) for the year ended March 31, 2022 was $0.3 million compared to $(0.9) million for the year ended March 31, 2021. The net change of $1.2 million is primarily attributable to a decrease in expense of $0.9 million as a result of a loss related to the extinguishment of debt in the prior year which did not recur in the current year, as well as a decrease in expense of $0.8 million as a result of interest expense on the aforementioned debt obligations in the prior year which did not recur during the current year. Furthermore, the Company earned approximately $0.5 million more in interest income on investments in the prior year as compared to the current year, and there is an increase in expense of $0.4 million in the current year due to the changes in foreign exchange rates of the Great British Pound to United States Dollar.

Liquidity and capital resources

Since our inception, we have not generated any revenue from product sales and have incurred significant operating losses and negative cash flows from our operations. We have not yet commercialized any of our product candidates, which are in

61

TABLE OF CONTENTS

various phases of preclinical and clinical development, and we do not expect to generate revenue from sales of any products for the foreseeable future, if at all.

Sources of liquidity

To date, we have financed our operations primarily with proceeds from the sale of equity securities and, to a lesser extent, proceeds from the issuance of debt. Through March 31, 2022, we had received net proceeds of $655.8 million from our sales of equity securities and $10.0 million from our incurrence of debt under the term loan facility with Hercules, which was repaid in full in December 2020. As of March 31, 2022, we had cash and cash equivalents and short-term investments of $395.7 million.

In July 2018, we completed our IPO and issued and sold 7,407,936 shares of our common stock at a public offering price of $15.00 per share, resulting in net proceeds of $101.2 million after deducting underwriting discounts, commissions and other offering expenses of approximately $9.9 million. In the fourth calendar quarter of 2019, we closed a registered public offering for the issuance and sale of 4,516,561 shares of our common stock at a public offering price of $13.61 per share and pre-funded warrants to purchase 2,200,000 shares of our common stock at a purchase price of $13.6099 per pre-funded warrant, which was equal to the public offering price per share of the common stock less the $0.0001 per share exercise price of each pre-funded warrant. We received aggregate net proceeds of approximately $85.6 million after deducting underwriting discounts, commissions and other offering expenses of approximately $5.8 million. In June 2020, we closed a second registered public offering for the issuance and sale of 3,478,261 shares of our common stock at a public offering price of $23.00 per share and pre-funded warrants to purchase 1,521,738 shares of our common stock at a purchase price of $22.9999 per pre-funded warrant, which was equal to the public offering price per share of common stock less the $0.0001 per share exercise price of each pre-funded warrant. We received aggregate net proceeds of approximately $107.8 million after deducting underwriting discounts, commissions and other offering expenses of approximately $7.2 million. In October 2020, we closed a third registered public offering for the issuance and sale of 5,625,000 shares of our common stock at a public offering price of $40.00 per share and pre-funded warrants to purchase 1,562,500 shares of our common stock at a purchase price of $39.9999 per pre-funded warrant, the public offering price per share of common stock less the $0.0001 per share exercise price of each pre-funded warrant. We received aggregate net proceeds of approximately $270.0 million after deducting underwriting discounts, commissions and other offering expenses of approximately $17.5 million.

In addition to registered public equity offerings, we also established an at-the-market offering program pursuant to a sales agreement that we entered into with SVB Leerink LLC, or the Agent, on August 8, 2019, or the 2019 Sales Agreement. Under the 2019 Sales Agreement, and prior to its amendment in June 2020, we could sell from time to time, at our option, up to an aggregate of $75.0 million of shares of our common stock. In June 2020, we amended the 2019 Sales Agreement to reduce the aggregate offering amount thereunder from $75.0 million to $30.0 million. We sold 287,559 shares of our common stock under the 2019 Sales Agreement for net proceeds of approximately $4.4 million. On August 11, 2020, in connection with our entry into separate sales agreement with the Agent, or the 2020 Sales Agreement, we and the Agent mutually agreed to terminate the 2019 Sales Agreement. Under the 2020 Sales Agreement, and prior to its amendment in October 2020, we could sell from time to time, at our option, up to an aggregate of $75.0 million of shares of our common stock. In October 2020, we amended the 2020 Sales Agreement to reduce the aggregate offering amount thereunder from $75.0 million to $62.5 million. We did not issue or sell any shares of our common stock under the 2020 Sales Agreement during the year ended March 31, 2022. For additional information, see Note 17, Subsequent events, of the "notes to Consolidated Financial Statements" contained in Part II, Item 8 of this Annual Report on Form 10-K.

Our incurrence of debt was conducted entirely under the Hercules Loan Agreement, as amended, pursuant to which we borrowed $10.0 million of a maximum of $40.0 million. On December 15, 2020, we entered into a Payoff Letter with Hercules and paid a total of $10.8 million to Hercules in connection therewith, representing the outstanding principal, accrued and unpaid interest, fees, costs and expense due and owed to Hercules, thereby terminating the Hercules Loan Agreement and the related loan documents.

Cash flows

The following table summarizes our cash flows for each of the periods presented:

62

TABLE OF CONTENTS

Operating activities

During the year ended March 31, 2022, net cash used in operating activities was $82.2 million, primarily resulting from our net loss of $118.0 million, partially offset by non-cash charges of $28.6 million, consisting of stock-based compensation expense of $24.3 million and $4.4 million of expense related to depreciation and amortization and net amortization of premiums and discounts on short-term investments, and an increase in cash of $7.2 million related to changes in our operating assets and liabilities. Changes in our operating assets and liabilities for the year ended March 31, 2022 consisted primarily of a $4.7 million increase in accrued expenses and other current liabilities, a net $2.5 million change in operating and financing right-of-use assets and lease liabilities, a $1.1 million increase in accounts payable and a $0.8 million increase in prepaid expenses and other current assets, as well as a $0.2 million increase in research and development incentives receivable from the United Kingdom government due to the timing and amount of qualifying expenditures.

During the year ended March 31, 2021, net cash used in operating activities was $61.4 million, primarily resulting from our net loss of $80.9 million, partially offset by an increase in non-cash charges of $16.0 million, primarily consisting of stock-based compensation expense, and an increase in cash of $3.5 million related to changes in our operating assets and liabilities. Changes in our operating assets and liabilities for the year ended March 31, 2021 consisted primarily of a $3.4 million increase in accrued expenses and other current liabilities, a net $2.5 million change in operating and financing right-of-use assets and lease liabilities, a $1.7 million decrease in prepaid expenses and other current assets, a $1.0 million decrease in accounts payable and a $0.3 million decrease in research and development incentives receivable from the United Kingdom government due to the timing and amount of our qualifying expenditures. The changes in accounts payable were primarily due to the timing of vendor invoicing and payments.

Investing activities

During the year ended March 31, 2022, net cash used in investing activities was $1.8 million, consisting of $255.7 million in purchases of available for sale securities and $2.3 million in purchases of property, plant and equipment, offset by $256.3 million in proceeds from sales and maturities of short-term investments.

During the year ended March 31, 2021, net cash used in investing activities was $188.8 million, consisting of $392.4 million in purchases of available for sale securities which were primarily driven by the receipt of proceeds from two registered public offerings during the fiscal year ended March 31, 2021, as well as $2.4 million in purchases of property, plant and equipment, partially offset by $206.1 million in proceeds from sales and maturities of short-term investments.

Financing Activities

During the year ended March 31, 2022, net cash provided by financing activities was $6.6 million, consisting primarily of $6.9 million in proceeds from the exercise of stock options.

During the year ended March 31, 2021, net cash provided by financing activities was $372.5 million, consisting of $286.1 million from the issuance of common stock, $91.7 million from the issuance of pre-funded warrants to purchase common stock, $5.7 million in proceeds from the exercise of stock options, partially offset by $10.0 million in debt payments under the Hercules Loan Agreement and $0.8 million of fees associated with the extinguishment of the obligations under the Hercules Loan Agreement.

Hercules Loan Agreement

On August 8, 2019 and as amended on June 1, 2020, we and certain of our affiliates entered into the Hercules Loan Agreement with Hercules, which provided for aggregate borrowings of up to $40 million in the form of term loans. We borrowed $10.0 million at closing under the Hercules Loan Agreement in August 2019 and subject to the achievement of certain milestones, had the ability to borrow the unused $30.0 million available in three separate $10.0 million advances

63

TABLE OF CONTENTS

between October 1, 2020 and December 15, 2020, July 1, 2020 and June 30, 2021, and July 1, 2021 and December 15, 2021, respectively.

On December 15, 2020, we entered into a Payoff Letter with respect to the Hercules Loan Agreement. Pursuant to the Payoff Letter, we paid a total of $10.8 million to Hercules, representing the outstanding principal, accrued and unpaid interest, fees, costs and expenses due and owed to Hercules under the Hercules Loan Agreement. Upon the execution of the Payoff Letter, in repayment of all of our outstanding obligations thereunder, the Hercules Loan Agreement and the related loan documents were terminated.

Borrowings under the Hercules Loan Agreement bore interest at a rate per annum equal to 8.75%. Under the Hercules Loan Agreement, we were required to make monthly interest-only payments through September 1, 2022. As of March 31, 2022, there was no amount outstanding under the Hercules Loan Agreement due and owing.

The Term Loan Facility with Hercules was secured by substantially all of our assets, excluding our intellectual property, and subject to certain exceptions and exclusions. All liens on our assets held by Hercules were released in connection with the execution of the Payoff Letter.

Funding requirements

Our plan of operation is to continue implementing our business strategy, continue research and development of RP1 and our other product candidates and continue to expand our research pipeline and our internal research and development capabilities. We expect our expenses to increase substantially in connection with our ongoing activities, particularly as we advance the preclinical activities and clinical trials of our product candidates and if and as we:

•conduct our current and future clinical trials with RP1, RP2 and RP3;

•further preclinical development of our RPx platform;

•operate, qualify and maintain our own in-house manufacturing facility;

•seek to identify and develop additional product candidates;

•seek marketing approvals for any of our product candidates that successfully complete clinical trials, if any;

•establish a sales, marketing and distribution infrastructure to commercialize any products for which we may obtain marketing approval;

•until our planned manufacturing facility is fully validated, continued limited manufacturing by third parties for clinical development.

•maintain, expand and protect our intellectual property portfolio;

•acquire or in-license other drugs and technologies; and

•add operational, financial and management information systems and personnel, including personnel to support our research and development programs, any future commercialization efforts and operations as a public company.

As of March 31, 2022, we had cash and cash equivalents and short-term investments of $395.7 million. We believe that our existing cash, cash equivalents and short-term investments as of March 31, 2022, will enable us to fund our overall operations into the second half of calendar 2024, excluding any confirmatory trial required by the FDA or other regulatory body. We have based these estimates on assumptions that may prove to be wrong, and we could utilize our available capital resources sooner than we expect.

Because of the numerous risks and uncertainties associated with the development of RP1 and other product candidates and programs, and because the extent to which we may enter into collaborations with third parties for development of our product candidates is unknown, we are unable to estimate the timing and amounts of increased capital outlays and operating expenses associated with completing the research and development of our product candidates. Our future capital requirements will depend on many factors, including those described in this section and above under “— Operating expenses — Research and development expenses.”

Developing novel biopharmaceutical products, including conducting preclinical studies and clinical trials, is a time-consuming, expensive and uncertain process that takes years to complete, and we may never generate the necessary data or results required to obtain marketing approval for any product candidates or generate revenue from the sale of any products for which we may obtain marketing approval. In addition, our product candidates, if approved, may not achieve commercial success. Our commercial revenues, if any, will be derived from sales of therapies that we do not expect to be commercially

64

TABLE OF CONTENTS

available for many years, if ever. Accordingly, we will need to obtain substantial additional funds to achieve our business objectives.

Adequate additional funds may not be available to us on acceptable terms, or at all. We do not currently have any committed external source of funds. To the extent that we raise additional capital through the sale of our equity or convertible debt securities, our shareholders’ interest may be diluted, and the terms of these securities may include liquidation or other preferences and anti-dilution protections that could adversely affect the rights of our common stockholder. Additional debt or preferred equity financing, if available, may involve agreements that include restrictive covenants that may limit our ability to take specific actions, such as incurring debt adversely impact our ability to conduct our business, and may require the issuance of warrants, which could potentially dilute your ownership interest.

If we raise additional funds through collaborations, strategic alliances or licensing arrangements with third parties, we may have to relinquish valuable rights to our technology, future revenue streams, research programs, or product candidates or grant licenses on terms that may not be favorable to us. If we are unable to raise additional funds through equity or debt financings or collaborations, strategic alliances or licensing arrangements with third parties when needed, we may be required to delay, limit, reduce and/or terminate our product development programs or any future commercialization efforts or grant rights to develop and market product candidates that we would otherwise prefer to develop and market ourselves.

Contractual obligations and commitments

We have entered into arrangements that contractually obligate us to make payments that will affect our liquidity and cash flows in future periods. Our contractual obligations primarily consist of our obligations under our operating and financing leases, as well as costs associated with contracts entered into in the normal course of business with CROs, CMOs and other third parties for clinical trials and preclinical research studies and testing.

As of March 31, 2022, the aggregate amount of future lease payments is approximately $60.0 million, with $3.6 million due within one year. For additional information on our leases and timing of future payments, see Note 12 Commitments and contingencies, of the "notes to Consolidated Financial Statements" contained in Part II, Item 8 of this Annual Report on Form 10-K.

Manufacturing and research commitments include agreements that are enforceable and legally binding on us and that specify all significant terms, including fixed or minimum quantities to be purchased; fixed, minimum or variable price provisions; and the approximate timing of the transaction. As of March 31, 2022, the aggregate amount of non-cancelable purchase obligations related to such manufacturing commitments are approximately $2.0 million and all of this balance is due within one year.

Collaborations

BMS

In February 2018, we entered into a Clinical Trial Collaboration and Supply Agreement with Bristol-Myers Squibb Company, or BMS. Pursuant to the agreement, BMS is providing to us, at no cost, nivolumab, its anti-PD-1 therapy, for use in combination with RP1 in our ongoing Phase 1/2 clinical trial. Under the agreement, we will sponsor, fund and conduct the clinical trial in accordance with an agreed-upon protocol. BMS granted us a non-exclusive, non-transferrable, royalty-free license (with a right to sublicense) under its intellectual property to use nivolumab in the clinical trial and has agreed to supply nivolumab, at no cost to us, for use in the clinical trial. Both parties will own the study data produced in the clinical trial, other than study data related solely to nivolumab, which will belong solely to BMS, or study data related solely to RP1, which will belong solely to us. In January 2020, this agreement was expanded to cover an additional cohort of 125 patients with anti-PD-1 failed melanoma.

Unless earlier terminated, the agreement will remain in effect until (i) the completion of the clinical trial, (ii) all related clinical trial data have been delivered to both parties and (iii) the completion of any statistical analyses and bioanalyses contemplated by the clinical trial protocol or any analysis otherwise agreed upon by the parties. The agreement may be terminated by either party (x) in the event of an uncured material breach by the other party, (y) in the event the other party is insolvent or in bankruptcy proceedings or (z) for safety reasons. Upon termination, the licenses granted to us to use nivolumab in the clinical trial will terminate. The agreement contains representations, warranties, undertakings and indemnities customary for a transaction of this nature.

In April 2019, we entered into a separate agreement with BMS on terms similar to the terms set forth in the agreement described above, pursuant to which BMS will provide, at no cost to us, nivolumab for use in our Phase 1 clinical trial of RP2 in combination with nivolumab.

65

TABLE OF CONTENTS

Regeneron

In May 2018, we entered into a Master Clinical Trial Collaboration and Supply Agreement with Regeneron Pharmaceuticals, Inc., or Regeneron. Pursuant to the agreement we agreed to undertake one or more clinical trials with Regeneron for the administration of our product candidates in combination with cemiplimab, an anti-PD-1 therapy developed by Regeneron, across multiple solid tumor types, the first of which is our ongoing Phase 2 clinical trial testing RP1 in combination with cemiplimab versus cemiplimab alone in patients with CSCC. Each clinical trial will be conducted pursuant to an agreed study plan which, among other things, will identify the name of the sponsor and which party will manage the particular study, and include the protocol, the budget and a schedule of clinical obligations. The first study plan related to the Phase 2 clinical trial in CSCC has been agreed.

Pursuant to the terms of the agreement, each party granted the other party a non-exclusive license of their respective intellectual property and agreed to contribute the necessary resources needed to fulfill their respective obligations, in each case, under the terms of agreed study plans. Development costs of a particular clinical trial will be split equally. The agreement contains representations, warranties, undertakings and indemnities customary for a transaction of this nature. The agreement also contains certain time-based covenants that restrict us from entering into a third-party arrangement with respect to the use of our product candidates in combination with an anti-PD-1 therapy and that restrict Regeneron from entering into a third-party arrangement with respect to the use of cemiplimab in combination with an HSV-1 virus, in each case, for the treatment of a tumor type that is the subject of a clinical trial to which the covenants apply. Unless otherwise mutually agreed in a future study plan, these covenants are only applicable to our ongoing Phase 2 clinical trial in CSCC.

The agreement may be terminated by either party if (i) there is no active study plan for which a final study report has not been completed and the parties have not entered into a study plan for an additional clinical trial within a period of time after the delivery of the most recent final study report or (ii) in the event of a material breach.

Critical accounting policies and estimates

Our management’s discussion and analysis of financial condition and results of operations is based on our consolidated financial statements, which have been prepared in accordance with generally accepted accounting principles in the United States. The preparation of our consolidated financial statements and related disclosures requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities, costs and expenses and the disclosure of contingent assets and liabilities in our consolidated financial statements. We base our estimates on historical experience, known trends and events and various other factors that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. We evaluate our estimates and assumptions on an ongoing basis. Our actual results may differ from these estimates under different assumptions or conditions.

While our significant accounting policies are described in greater detail in Note 2 to our consolidated financial statements appearing elsewhere in this Annual Report on Form 10-K, we believe that the following accounting policies are those most critical to the judgments and estimates used in the preparation of our consolidated financial statements.

Accrued research and development expenses

As part of the process of preparing our consolidated financial statements, we are required to estimate our accrued research and development expenses. This process involves reviewing open contracts and purchase orders, communicating with our personnel to identify services that have been performed on our behalf and estimating the level of service performed and the associated cost incurred for the service when we have not yet been invoiced or otherwise notified of actual costs. The majority of our service providers invoice us in arrears for services performed, on a pre-determined schedule or when contractual milestones are met; however, some require advanced payments. We make estimates of our accrued expenses as of each balance sheet date in the consolidated financial statements based on facts and circumstances known to us at that time. Examples of estimated accrued research and development expenses include fees paid to:

•CROs in connection with performing research activities and conducting preclinical studies and clinical trials on our behalf;

•CMOs in connection with the production of preclinical and clinical trial materials;

•investigative sites or other service providers in connection with clinical trials;

•vendors in connection with preclinical and clinical development activities; and

•vendors related to product manufacturing and development and distribution of preclinical and clinical supplies.

66

TABLE OF CONTENTS

We base our expenses related to preclinical studies and clinical trials on our estimates of the services received and efforts expended pursuant to quotes and contracts with multiple CMOs and CROs that supply, conduct and manage preclinical studies and clinical trials on our behalf. The financial terms of these agreements are subject to negotiation, vary from contract to contract and may result in uneven payment flows. There may be instances in which payments made to our vendors will exceed the level of services provided and result in a prepayment of the expense. Payments under some of these contracts depend on factors such as the successful enrollment of patients and the completion of clinical trial milestones. In accruing service fees, we estimate the time period over which services will be performed and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from the estimate, we adjust the accrual or the amount of prepaid expenses accordingly. Although we do not expect our estimates to be materially different from amounts actually incurred, our understanding of the status and timing of services performed relative to the actual status and timing of services performed may vary and may result in reporting amounts that are too high or too low in any particular period. To date, there have not been any material adjustments to our prior estimates of accrued research and development expenses.

Stock-based compensation

We issue stock-based awards to employees, directors, consultants and non-employees in the form of stock options and restricted stock units. We measure such stock-based awards in accordance with ASC 718, Compensation — Stock Compensation, which requires all stock-based awards to be recognized in the consolidated statements of operations and comprehensive loss based on their fair value on the date of the grant and the related compensation expense for those awards is recognized over the requisite service period, which is generally the vesting period of the respective award. We have, to date, only issued stock-based awards with service-based vesting conditions and record the expense for these awards using the straight-line method. The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes option-pricing model, which requires inputs based on certain subjective assumptions, including the expected stock price volatility, the expected term of the option, the risk-free interest rate for a period that approximates the expected term of the option, and our expected dividend yield. See Note 9 of the "Notes to Consolidated Financial Statements" contained in Part II, Item 8 of this Annual Report on Form 10-K for more information. Forfeitures are accounted for as they occur. The fair value of each stock-based award is estimated on the date of grant based on the fair value of our common stock on that same date.

We classify stock-based compensation expense in our consolidated statements of operations in the same manner in which the award recipient’s payroll costs are classified or in which the award recipient’s service payments are classified.

Recently issued accounting pronouncements

Refer to Note 2, summary of significant accounting policies of the “Notes to Consolidated Financial Statements” contained in Part II, Item 8 of this Annual Report on Form 10-K for a description of recent accounting pronouncements that are applicable to our business and may potentially have an impact on our financial position and results of operations

Emerging growth company status

As an “emerging growth company,” the Jumpstart Our Business Startups Act of 2012 permits us to take advantage of an extended transition period to comply with new or revised accounting standards applicable to public companies until those standards would otherwise apply to private companies. We have irrevocably elected to “opt out” of this provision and, as a result, we will comply with new or revised accounting standards when they are required to be adopted by public companies that are not emerging growth companies.