Tectonic Therapeutic, Inc. (TECX)

Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

The following discussion and analysis of our financial condition and results of operations should be read in conjunction with our financial statements and related notes included elsewhere in this Annual Report on Form 10-K. The following discussion contains forward-looking statements that are based upon current expectations that involve risks, uncertainties and assumptions. Our actual results could differ materially from those anticipated in these forward-looking statements as a result of many factors, including those discussed under “Risk Factors” and elsewhere in this Annual Report on Form 10-K. Please also see the section titled “Special Note Regarding Forward-Looking Statements.”

Unless otherwise indicated or the context otherwise requires, references in this “Management’s Discussion and Analysis of Financial Condition and Results of Operations” section to the Company, “we,” “us,” and “our” refer to the business and operations of Tectonic Operating Company, Inc. (previously Tectonic Therapeutic, Inc., referred to as “Legacy Tectonic”) and its consolidated subsidiaries prior to the Merger, and the business and operations of Tectonic Therapeutic, Inc. (previously AVROBIO, Inc., referred to as “AVROBIO”) and its consolidated subsidiaries following the Merger.

Overview

We are a biotechnology company focused on the discovery and development of therapeutic proteins and antibodies that modulate the activity of GPCRs. The discovery of biologics that can modulate GPCRs has historically been quite challenging. We have developed a proprietary technology platform called GEODe™, with the aim of addressing these challenges to enable the discovery and development of GPCR-targeted biologic medicines that can modify the course of disease. We focus on areas of significant unmet medical need, often where therapeutic options are poor or nonexistent, as these are areas where new medicines have the potential to improve patient quality of life or extend duration of life.

Our lead asset, TX45, is an Fc-relaxin fusion molecule that activates the RXFP1 receptor, the GPCR target of the hormone, relaxin. In September 2024, we announced favorable results from a Phase 1a trial evaluating safety, tolerability and pharmacokinetic (“PK”) and pharmacodynamic (“PD”) properties for TX45. In this trial, TX45 was well-tolerated with no drug-related severe adverse events, no observed immunogenicity and demonstrated a favorable PK/PD relationship. Renal plasma flow was measured in each patient at several time points as a pharmacodynamic marker. This data was used to develop an exposure-response model which enabled the selection of doses for the APEX Phase 2 trial.

We are currently evaluating TX45 in a Phase 1b hemodynamic clinical trial and in a Phase 2 clinical trial. Part A of the TX45 Phase 1b hemodynamic clinical trial is a single dose IV, open-label clinical trial evaluating the safety, tolerability and acute hemodynamic effects of TX45 in patients with Group 2 PH in Heart Failure with Preserved Ejection Fraction (“PH-HFpEF”). We have completed dosing of all 19 patients in the Part A of the Phase 1b trial. A preliminary analysis of hemodynamic data from 16 out of 19 patients demonstrated improvements which met and or exceeded our prespecified goals and demonstrated that TX45 both improved left heart function and pulmonary hemodynamics over the 8 hour period post dosing which was evaluated. Part B of the Phase 1b trial which is assessing acute hemodynamics effects of TX45 in patients with Group 2 PH-HFrEF is expected to enroll the first patient in the first half of 2025 with data expected to be announced in the second half of 2025. We dosed our first subject in the APEX Phase 2 clinical trial in October 2024. The APEX Phase 2 clinical trial is a global, 24-week, placebo-controlled trial designed to evaluate the safety and efficacy TX45 administered subcutaneously (“SC”) in subjects with PH-HFpEF. Subjects will be randomized to 300 mg SC (2ml injection) once monthly of TX45, 300 mg SC once every other week of TX45, or placebo. We expect topline trial results from the APEX trial in 2026.

We are also evaluating TX002100 (“TX2100”) as our second development candidate for the treatment of Hereditary Hemorrhagic Telangiectasia (“HHT”), the second most common genetic bleeding disorder with no approved therapy. TX2100 is a VHH-Fc fusion antagonist antibody that binds to an undisclosed GPCR target (“GPCR3”) which plays a key role in pathogenic angiogenesis. A rodent surrogate of TX2100 demonstrated reduced arteriovenous malformation development and bleeding in an animal model of HHT. A 4-week non-human primate dose-range study with a functionally equivalent precursor to TX2100 showed no treatment-related toxicity observed at doses up to 100 mg/kg. A formulation supporting TX2100 SC dosing has been identified. Both IND enabling NHP GLP toxicology studies and technical development activities to generate GMP drug supply and drug product for TX2100 is expected to start in the second quarter of 2025.We expect to initiate a Phase 1 clinical trial for TX2100 in the fourth quarter of 2025 or the first quarter of 2026, subject to the results of IND enabling studies.

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Merger with AVROBIO

On January 30, 2024, Legacy Tectonic entered into the Agreement and Plan of Merger and Reorganization (“Merger Agreement”) with AVROBIO and Alpine Merger Subsidiary, Inc. (“Merger Sub”). Pursuant to the Merger Agreement and the satisfaction of the conditions described in the Merger Agreement, on June 20, 2024, Merger Sub merged with and into Legacy Tectonic, with Legacy Tectonic surviving as a wholly owned subsidiary of AVROBIO (the “Merger”). The Merger Agreement and the transactions contemplated therein were approved by the members of the AVROBIO Board of Directors and Legacy Tectonic Board of Directors. Subject to the terms and conditions of the Merger Agreement, at the effective time, (a) each outstanding share of Legacy Tectonic common stock (including shares of Legacy Tectonic common stock issued upon conversion of its preferred stock and the shares issued pursuant to that certain Subscription Agreement dated January 30, 2024, entered into among Legacy Tectonic and the investors party thereto (the “Subscription Agreement”) and conversion of the SAFEs into the right to receive a number of shares of AVROBIO common stock equal to the exchange ratio; and (b) each then outstanding Legacy Tectonic stock option that was outstanding and unexercised immediately prior to the effective time was assumed by AVROBIO, subject to the exchange ratio.

Immediately after the Merger, AVROBIO securityholders as of immediately prior to the Merger owned approximately 24.8% of the outstanding shares of our capital stock on a diluted basis. Immediately after the Merger, Legacy Tectonic securityholders owned approximately 38.5% of the outstanding shares of our capital stock on a diluted basis. Investors participating in the Subscription Agreement and the SAFEs owned approximately 27.1% and 9.6% of the outstanding shares of our capital stock, respectively, on a diluted basis.

Legacy Tectonic stockholders received 10,956,614 shares of AVROBIO common stock in connection with the Merger, including 11,447 shares of AVROBIO common stock subject to vesting terms, based on the number of shares of Legacy Tectonic common stock outstanding immediately prior to the Merger, including Legacy Tectonic restricted stock, the number of shares of Legacy Tectonic common stock issued to investors participating in the Subscription Agreement and SAFEs, and Legacy Tectonic convertible preferred stock outstanding immediately prior to the Merger, which was converted into shares of Legacy Tectonic common stock on a one-for-one basis immediately prior to the closing of the Merger.

Subscription Agreement

Concurrently with the closing of the Merger, on June 20, 2024, certain investors completed the purchase of shares of Legacy Tectonic common stock pursuant to the Subscription Agreement for an aggregate purchase price of $96.6 million. The shares of Legacy Tectonic common stock that were issued pursuant to the Subscription Agreement were converted into 4,163,606 shares of our common stock upon the closing of the Merger based on the exchange ratio, pursuant to the Merger Agreement.

Components of our Results of Operations

Revenue

We have not generated any revenue since our inception and do not expect to generate any revenue from the sale of products in the foreseeable future, if at all. If our development efforts for our product candidates are successful and result in regulatory approval, or if we enter collaboration or license agreements with third parties, we may generate revenue in the future from product sales or payments from collaboration or license agreements, or any combination thereof. We cannot predict if, when or to what extent we will generate revenue from the commercialization and sale of our product candidates. We may never succeed in obtaining regulatory approval for any of our product candidates.

Operating Expenses

Research and Development Expenses

Research and development expenses consist of costs incurred for our research activities, including our discovery efforts and the development of our programs and platform. These expenses include:

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employee-related expenses, including salaries and bonuses, related benefits and stock-based compensation expense, for employees engaged in research and development functions;

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expenses incurred in connection with research and the preclinical and clinical development of our programs and our product candidates, including fees paid to contract research organizations (“CROs”);

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costs related to manufacturing material for our preclinical studies and clinical trials, including fees paid to contract development and manufacturing organizations (“CDMOs”);

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laboratory supplies, consumables and other research materials;

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facilities, depreciation and other expenses related to research and development activities, which include direct or allocated expenses for rent and maintenance of facilities, and utilities;

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costs related to compliance with regulatory requirements; and

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payments made under third-party licensing agreements.

We expense all research and development costs in the periods in which they are incurred. Costs for certain development activities are recognized based on our evaluation of the progress to completion of specific tasks using information and data provided to us by our vendors and third-party service providers. Nonrefundable advance payments for goods or services to be received in the future for use in research and development activities are recorded as prepaid expenses. Such amounts are recognized as an expense when the goods have been delivered or the services have been performed, or when it is no longer expected that the goods will be delivered or the services rendered. Upfront payments under license agreements are expensed upon receipt of the license, and annual maintenance fees under license agreements are expensed in the period in which they are incurred. Milestone payments under license or collaboration agreements are accrued, with a corresponding expense being recognized, in the period in which the milestone is determined to be probable of achievement and the related amount is reasonably estimable.

Our direct research and development expenses relate to the development of TX45 and TX2100, as well as the nonclinical safety pharmacology and toxicology testing of our product candidates. Our external services expenses consist of the external costs and fees paid to consultants and other research laboratories in connection with our preclinical development and clinical development activities.

Costs that are deployed across multiple internal programs, including programs aimed at the discovery and development of potential therapies for fibrotic disease, and our platform technology and are not directly attributable to any single program are not allocated to any single program and, as such, are not separately classified. These costs include multi-program employee-related costs, cross-program payments made under third-party licensing agreements, costs of laboratory supplies and facilities expenses, including rent, depreciation and other indirect costs, the costs of our discovery efforts and projects, and other expenses.

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 cannot determine with certainty the timing of initiation, the duration or the completion costs of current or future preclinical studies and clinical trials of our product candidates due to the inherently unpredictable nature of preclinical and clinical development. Clinical and preclinical development timelines, the probability of success and development costs can differ materially from expectations. We anticipate that we will make determinations as to which product candidates to pursue and how much funding to direct to each product candidate on an ongoing basis in response to the results of ongoing and future preclinical studies and clinical trials, regulatory developments and our ongoing assessments as to each product candidate’s commercial potential. We will need to raise substantial additional capital in the future. Our clinical development costs are expected to increase significantly as we commence clinical trials. Our future expenses may vary significantly each period based on factors such as:

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expenses incurred to conduct preclinical studies required to advance our product candidates into clinical development;

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per patient trial costs, including based on the number of doses that patients received;

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the number of patients who enroll in each trial;

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the number of trials required for approval;

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the number of sites included in the trials;

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the countries in which the trials are conducted;

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the length of time required to enroll eligible patients;

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the drop-out or discontinuation rates of patients;

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potential additional safety monitoring requested by regulatory agencies;

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the duration of patient participation in the trials and follow-up;

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the phase of development of the product candidate;

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third-party contractors failing to comply with regulatory requirements or meet their contractual obligations to us in a timely manner, or at all;

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the ability to manufacture our product candidates;

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regulators or institutional review boards requiring that we or our investigators suspend or terminate clinical development for various reasons, including noncompliance with regulatory requirements or a finding that the participants are being exposed to unacceptable health risks; and

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the efficacy and safety profile of our product candidates.

General and Administrative Expenses

General and administrative expenses consist primarily of employee-related costs, including salaries and bonuses, related benefits and stock-based compensation expense, for our personnel in executive, legal, accounting, human resources and other administrative functions. General and administrative expenses also include legal fees relating to patents and corporate matters, professional fees paid for accounting, auditing, consulting and tax services, insurance, travel expenses, office and information technology costs and facilities and utilities, depreciation and other expenses related to general and administrative activities.

We anticipate that our general and administrative expenses will increase in the future as we expect to incur increased accounting, audit, legal, regulatory, compliance, director and officer insurance, and investor and public relations expenses associated with operating as a public company. We also expect to incur additional intellectual property-related expenses as we file patent applications to protect innovations arising from our research and development activities.

Other Income (Expense), Net

Loss on Issuance of SAFE Liabilities and Change in Fair Value of SAFE Liabilities

In October and December 2023, Legacy Tectonic issued SAFEs for proceeds of $34.1 million. The SAFEs were recorded as liabilities in the Consolidated Balance Sheets at their fair value on the issuance dates. Until redemption on June 20, 2024, the SAFEs were measured at a fair value on a recurring basis, with subsequent changes in fair value recorded in other income and expenses on the Consolidated Statement of Operations and Comprehensive Loss.

Interest Income

Interest income primarily consists of interest earned on money market funds, which are included in cash and cash equivalents in the Consolidated Balance Sheets.

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Results of Operations

Comparison of the Years Ended December 31, 2024 and 2023

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

Research and Development Expenses

Total research and development expenses increased $4.4 million for the year ended December 31, 2024 compared to the year ended December 31, 2023. The increase in research and development expense was primarily the result of increased CRO and CDMO costs related to the discovery and development of TX2100.

General and Administrative Expenses

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General and administrative expenses increased $9.0 million for the year ended December 31, 2024 compared to the year ended December 31, 2023. The increase is primarily attributable to an increase in employee-related expenses and professional and consulting expenses. Employee-related expenses increased $3.9 million for the year ended December 31, 2024 compared to the year ended December 31, 2023 due to an increase in stock-based compensation for stock-based awards, the expense for the modification of certain stock options and severance costs related the reduction in force that occurred during the year ended December 31, 2024. Professional and consulting expenses increased $4.8 million for the year ended December 31, 2024 compared to the year ended December 31, 2023. The increase in professional and consulting expenses was due to an increase in services fees to support Merger-related activities and an increase in audit, legal and administrative services to support our operations as a public company.

Other (Expense) Income, Net

Change in Fair Value of SAFE Liabilities

The SAFE liabilities loss of $3.6 million resulted from the remeasurement of the SAFE liabilities to fair value during the year ended December 31, 2024.

Interest Income

Interest income increased by $3.7 million for the year ended December 31, 2024 compared to the year ended December 31, 2023 primarily due to an increase in cash and cash equivalents as a result of the Merger.

Liquidity and Capital Resources

Sources of Liquidity

Since our inception, we have incurred significant operating losses. We expect to incur significant expenses and operating losses for the foreseeable future as we advance the preclinical and clinical development of our research programs and product candidates. We expect that our research and development and general and administrative costs will increase in connection with conducting additional preclinical studies and clinical trials for our current and future research programs and product candidates, contracting with CDMOs to support preclinical studies and clinical trials, expanding our intellectual property portfolio, and providing general and administrative support for our operations. As a result, we will need additional capital to fund our operations, which we may obtain from additional equity or debt financings, collaborations, licensing arrangements or other sources.

We do not currently have any approved products and have never generated any revenue from product sales. We have funded our operations with proceeds from the sale of convertible preferred stock, the issuance of convertible promissory notes, the Merger, and sale of common stock. In February 2025, we sold shares of our common stock under a securities purchase agreement in exchange for gross proceeds of $185 million. As of December 31, 2024, we had $141.2 million in cash and cash equivalents and an accumulated deficit of $148.6 million. Based on our current business plans, management believes that our cash, cash equivalents and marketable securities on hand at December 31, 2024 are sufficient to meet our operating requirements for at least the next 12 months from the issuance of the consolidated financial statements included in this Annual Report on Form 10-K. We have based this estimate on assumptions that may prove to be wrong, and we could exhaust our capital resources sooner than we expect.

Cash Flows

The following table shows a summary of our cash flows for the years ended December 31, 2024 and 2023:

Operating Activities

During the year ended December 31, 2024, cash used in operating activities was $59.1 million. Cash used in operating activities was primarily used to fund our operations to develop our product candidates, resulting in a net loss of $58.0

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million and changes in our operating assets and liabilities of $10.3 million, partially offset by non-cash charges of $9.2 million related to the change in the fair value of the SAFE liabilities, stock-based compensation expense, depreciation and amortization expense and lease expense. The increase in operating assets and liabilities relates to accrued expenses for the Merger and prepayments to the CRO.

During the year ended December 31, 2023, cash used in operating activities was $40.7 million. Cash used in operating activities was primarily used to fund our operations to development our product candidates, resulting in a net loss of $42.8 million and changes in our operating assets and liabilities of $0.6 million, partially offset by non-cash charges of $2.7 million related to the change in the fair value of the SAFE liabilities, stock-based compensation expense, depreciation and amortization expense and lease expense. The increase in operating assets and liabilities relates to accrued expenses, timing of vendor payments, and timing of lease repayments.

Investing Activities

During the year ended December 31, 2024 and 2023, net cash used in investing activities was $0.2 million and $0.3 million, respectively, related to purchases of property and equipment.

Financing Activities

During the year ended December 31, 2024, net cash provided by financing activities was $171.7 million, primarily due to net proceeds of $94.6 million from the sale of shares pursuant to the Subscription Agreement, $76.0 million in net proceeds and $1.6 million in proceeds from the exercise of stock options. Net cash provided by financing activities during the year ended December 31, 2023 was primarily due to the receipt of $34.1 million of proceeds from the issuance of SAFEs.

Funding Requirements

We expect our expenses to increase in connection with our ongoing activities, particularly as we continue the research and development of, continue or initiate clinical trials of, and seek marketing approval for, our product candidates including our lead product candidate TX45 and TX2100. In addition, if we obtain marketing approval for TX45, TX2100 or any of our other product candidates, we expect to incur significant commercialization expenses related to program sales, marketing, manufacturing and distribution to the extent that such sales, marketing and distribution are not the responsibility of potential collaborators. Furthermore, we expect to incur additional costs associated with operating as a public company. Accordingly, we will need to obtain substantial additional funding in connection with our continuing operations. If we are unable to raise capital when needed or on attractive terms, we would be forced to delay, reduce or eliminate our research and development programs or future commercialization efforts.

We expect our existing cash and cash equivalents, together with the net proceeds from the Merger and the sale of securities pursuant to the Subscription Agreement, will enable us to fund our operating expenses and capital expenditure requirements for at least the next twelve months. Our future capital requirements will depend on many factors, including:

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the scope, progress, results and costs of product discovery, preclinical studies and clinical trials;

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the scope, prioritization and number of our research and development programs;

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the costs, timing and outcome of regulatory review of our product candidate;

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our ability to access sufficient additional capital on a timely basis and on favorable terms;

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the costs and timing of process development and manufacturing scale-up activities associated with our product candidates and other programs as we advance them through preclinical and clinical development;

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our ability to establish and maintain collaborations on favorable terms, if at all;

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the achievement of milestones or occurrence of other developments that trigger payments under the license agreements and any other collaboration agreements we enter into;

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the extent to which we are obligated to reimburse, or entitled to reimbursement of, clinical trial costs under collaboration agreements, if any;

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the costs of preparing, filing and prosecuting patent applications, maintaining and enforcing our intellectual property rights and defending intellectual property-related claims;

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the extent to which we acquire or in-license other product candidates and technologies;

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the costs of securing manufacturing arrangements for commercial production;

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the costs of operating as a publicly traded company;

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the costs of establishing or contracting for sales and marketing capabilities if we obtain regulatory approvals to market our product candidates; and

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the macroeconomic environment, including inflation and interest rates.

Identifying potential product candidates and conducting preclinical studies and clinical trials is a time-consuming, expensive and uncertain process that takes many years to complete, and we may never generate the necessary data or results required to obtain marketing approval and achieve product sales. In addition, our product candidates, if approved, may not achieve commercial success. Our commercial revenues, if any, will be derived from sales of product candidates that we do not expect to be commercially available for many years, if at all. Accordingly, we will need to continue to rely on additional financing to achieve our business objectives. Adequate additional financing may not be available to us on acceptable terms, or at all. Until such time, if ever, as we can generate substantial product revenues, we expect to finance our cash needs through a combination of equity offerings, debt financings, collaborations, strategic alliances and licensing arrangements. Debt financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends.

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

We expect to incur additional costs associated with operating as a public company. In addition, we anticipate that we will need substantial additional funding in connection with our continuing operations. Our projections of operating capital requirements are based on our current operating plan, which includes several assumptions that may prove to be incorrect and we may use all of our available capital resources sooner than we expect.

We currently have no ongoing material financing commitments, such as lines of credit or guarantees, that are expected to affect our liquidity over the next five years, other than our lease obligations.

Contractual Obligations & Commitments

We have entered into license agreements under which we are obligated to make specified milestone and royalty payments. The payment obligations under these agreements are contingent upon future events, such as our achievement of specified development, regulatory, and sales milestones, or generating product sales. Generally, the timing or likelihood of achieving these milestones or generating future product sales are not determinable. For further details regarding our significant contracts, and the commitments and contractual obligations contained within each contract, please refer to Note 11, License Agreements, and Note 12, Commitments and Contingencies, and to our consolidated financial statements included in this Annual Report on Form 10-K, which is incorporated herein by reference.

We have lease obligations including amounts due on leases of certain laboratory equipment and office and laboratory space under the terms of non-cancelable operating and finance leases. The leases expire at various times through 2027. Minimum lease payments are $3.0 million in 2025, $0.4 million in 2026, and $0.1 million in 2027. The commitment amounts are associated with contracts that are enforceable and legally binding and that specify all significant terms, including fixed or minimum services to be used, fixed, minimum or variable price provisions, and the approximate timing of the actions under the contracts. Such amounts do not include obligations under agreements that we can cancel without a significant penalty.

In addition, we enter into agreements in the normal course of business with vendors for preclinical research studies, clinical trials and other services and products for operating purposes. These contracts do not contain any minimum purchase commitments and are generally cancelable upon written notice. Payments due upon cancellation consist only of payments for services provided and expenses incurred up to the date of cancellation.

Critical Accounting Policies and Estimates

Our management’s discussion and analysis of our 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 (“GAAP”). The preparation of the consolidated financial statements requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosures of contingent assets and liabilities in our consolidated financial statements and the reported amounts of expenses during the reporting periods. We base our estimates on historical experience, known trends and events, and various other assumptions that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the

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carrying values of assets and liabilities recorded expenses that are not readily apparent from other sources. We evaluate our estimates and assumptions on an ongoing basis. Actual results may differ from these estimates.

While our significant accounting policies are described in the notes to our financial statements included elsewhere in this Annual Report, we believe that the following accounting policies are critical to understanding our historical and future performance, as these policies relate to the more significant areas involving management’s judgments and estimates.

Prepaid and Accrued Research and Development Expenses

As part of the process of preparing our consolidated financial statements, we are required to estimate our prepaid and accrued research and development expenses. This process involves estimating the level of service performed and the associated cost incurred for the services 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 advance payments. We make judgments and estimates of our prepaid and accrued research and development expenses as of each balance sheet date in the consolidated financial statements based on facts and circumstances known to us at that time, which includes corroboration of these estimates with the service providers. If the actual timing of the performance of services or the level of effort varies from the estimate, we adjust accrued expenses or prepaid expenses accordingly, which impact research and development expenses. To date, we have not experienced any material adjustments to our prior estimates of prepaid and accrued research and development expenses. Changes in these estimates that result in material changes to our accrued costs could materially affect our results of operations.

Stock-Based Compensation

We use the Black-Scholes-Merton (“BSM”) option pricing model. Prior to being publicly traded, the fair value of the Company’s common stock underlying the stock options was determined by the Board of Directors with assistance from management and, in part, on input from an independent third-party valuation firm. The Board of Directors determined the fair value of common stock by considering a number of objective and subjective factors, including valuations of comparable companies, sales of convertible preferred stock, operating and financial performance, the lack of liquidity of the Company’s common stock and the general and industry-specific economic outlook. Subsequent to the Merger, the fair value of the Company’s common stock is based on the closing quoted market price of its common stock as reported by the NASDAQ Select Market on the date of grant.

In addition to the fair value of the Company’s stock, the estimated fair value of options granted to employees and non-employees requires a subjective estimate for the following input:

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Expected Volatility— The estimated volatility is determined by evaluating the average historical volatility of a peer group of companies for the period preceding the stock option grant for a term that is approximately equal to the stock options’ expected term.

Recent Accounting Pronouncements

Recent accounting pronouncements are addressed in Note 2, Summary of Significant Accounting Policies and Basis of Presentation, in the Notes to the Consolidated Financial Statements included herein.

Smaller Reporting Company Status

We are a “smaller reporting company” as defined in the Exchange Act. We may take advantage of certain of the scaled disclosures available to smaller reporting companies and will be able to take advantage of these scaled disclosures for so long as the market value of the common stock held by non-affiliates is less than $250.0 million measured on the last business day of our second fiscal quarter, or our annual revenue is less than $100.0 million during the most recently completed fiscal year and the market value of the common stock held by non-affiliates is less than $700.0 million measured on the last business day of our second fiscal quarter.

As a result, the information in this Annual Report on Form 10-K and that we provide to our investors in the future may be different than what you might receive from other public reporting companies.

Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

Our management’s discussion and analysis of our financial condition and results of operations are based upon our consolidated financial statements included in this Annual Report on Form 10-K, which have been prepared by us in accordance with United States generally accepted accounting principles, or GAAP, and with Regulation S-X promulgated under the Exchange Act. This discussion and analysis should be read in conjunction with the consolidated financial statements and the notes thereto included elsewhere in this Annual Report on Form 10-K. Some of the information 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, includes forward-looking statements that involve risks and uncertainties. As a result of many factors, including those factors set forth in Part I, Item 1A. Risk Factors of this Annual Report on Form 10-K, our actual results could differ materially from the results described in or implied by the forward-looking statements contained in the following discussion and analysis.

Overview

We are a gene therapy company with a purpose to free people from a lifetime of genetic disease. Our company has been focused on developing potentially curative HSC gene therapies to treat patients with rare diseases following a single dose treatment regimen. The gene therapies we had been developing employ HSCs that are harvested from the patient and then modified with a lentiviral vector to insert the equivalent of a functional copy of the gene that is mutated in the target disease. We believe that our approach, which is designed to transform stem cells from patients into therapeutic products, has the potential to provide curative benefit for a range of diseases. Our development focus has been on a group of rare genetic diseases referred to as lysosomal disorders, some of which today are primarily managed with enzyme replacement therapies, or ERTs.

On July 12, 2023, following a comprehensive review of our business by the AVROBIO Board, we announced our intention to halt development of our programs and explore strategic alternatives focused on maximizing stockholder value, which may include, but are not limited to, an acquisition, a merger, business combination or divestiture.

Subsequently, in connection with ongoing cost reduction efforts related to our ongoing review of potential strategic alternatives, we have terminated all Company-sponsored treatment-related and Company-sponsored long-term follow-up clinical studies relating to our AVR-RD-02, or Gaucher disease type 1, program, and Company-sponsored long term follow-up studies relating to our AVR-RD-01, or Fabry disease, program (which we previously deprioritized). In addition, in September 2023, we terminated our agreements with the University of Manchester for the license and development of a gene therapy for MPSII and discontinued our AVR-RD-05, or Hunter syndrome gene therapy program. Previously, in June 2023, we sold our cystinosis gene therapy program to Novartis. As of the date of the filing of this Annual Report, we currently have a total of three gene therapy product candidates, none of which are currently in active clinical development, including AVR-RD-02 for the treatment of Gaucher disease type 1 and type 3, AVR-RD-03 for the treatment of Pompe disease and AVR-RD-01 for the treatment of Fabry disease.

After a comprehensive review of strategic alternatives, including identifying and reviewing potential candidates for a strategic transaction, on January 30, 2024, AVROBIO entered into the Merger Agreement, with Merger Sub and Tectonic, pursuant to which Merger Sub will merge with and into Tectonic, with Tectonic surviving as AVROBIO’s wholly-owned subsidiary. The merger was unanimously approved by the AVROBIO Board, and the AVROBIO Board resolved to recommend approval of the Merger Agreement to AVROBIO stockholders. In connection with the merger, certain investors have agreed to purchase shares of Tectonic common stock at a purchase price of $12.39908 per share, subject to and immediately prior to the closing of the merger, pursuant to the terms of the Subscription Agreement, and certain investors have consummated or will consummate certain additional purchases of Tectonic common stock pursuant to the Tectonic SAFEs for an aggregate purchase price among the transactions contemplated by the Subscription Agreement and such Tectonic SAFEs of approximately $130.7 million. At the effective time of the merger, each share of then-outstanding Tectonic common stock will be converted into the right to receive a number of shares of AVROBIO common stock, equal to the exchange ratio as set forth in the Merger Agreement. Concurrently with the closing of the merger, and assuming approval by AVROBIO stockholders, AVROBIO anticipates effecting a reverse stock split at a ratio in the range between 1:3 to 1:30, inclusive. Additionally, at or prior to the effective time of the merger, AVROBIO and a rights agent will enter into a CVR Agreement, pursuant to which AVROBIO stockholders of record as of immediately prior to such effective time (including holders of AVROBIO common stock issued upon settlement of the AVROBIO RSUs) will receive one non-transferable CVR for each outstanding share of AVROBIO common stock held by such stockholder on such date.

The closing of the merger is subject to approval by AVROBIO stockholders and Tectonic stockholders, as well as other customary closing conditions, including the effectiveness of a registration statement on Form S-4 filed with the SEC in connection with the transaction and Nasdaq’s approval of the listing of the shares of the AVROBIO common stock to be issued in connection with the proposed merger. The closings of the private financings are conditioned upon the satisfaction or

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waiver of the conditions to the closing of the merger as well as certain other conditions. If the transactions are completed, the business of Tectonic will continue as the business of the combined company.

AVROBIO’s future operations are highly dependent on the success of the merger and there can be no assurances that the merger will be successfully consummated. There can be no assurance that the strategic review process or any transaction relating to a specific asset, including the merger and any AVROBIO asset sale (as defined below), will result in AVROBIO pursuing such a transaction(s), or that any transaction(s), if pursued, will be completed on terms favorable to AVROBIO and its stockholders in the existing AVROBIO entity or any possible entity that results from a combination of entities. If the strategic review process is unsuccessful, and if the merger is not consummated, the AVROBIO Board may decide to pursue a dissolution and liquidation of AVROBIO.

Since our inception in 2015, we have devoted substantially all of our resources to organizing and staffing our company, business planning, raising capital, acquiring or discovering product candidates and securing related intellectual property rights, conducting discovery, research and development activities for our programs and planning for potential commercialization. To date, we have not generated any product revenue and have financed our operations primarily through the private placement of our securities and through public offerings of our common stock. Through December 31, 2023, we had received gross cash proceeds of $87.5 million from sales of our preferred stock; gross cash proceeds, before deducting underwriting discounts and commissions and expenses, of $428.1 million from sales of our common stock through our IPO and follow-on offerings; gross cash proceeds, before deducting commissions and expenses, of $23.5 million from sales of our common stock under our prior ATM facility; $15.0 million drawn in term loans under our Term Loan Agreement, which was repaid in full and terminated on June 9, 2023; and gross proceeds, before deducting transaction costs, of $87.5 million from the sale of our cystinosis gene therapy program.

Additionally, we have incurred significant operating losses. Our ability to generate product revenue sufficient to achieve profitability will depend heavily on the successful development and eventual commercialization of one or more of our current or future product candidates and programs. Our net income (losses) were $12.2 million and $(105.9) million for the years ended December 31, 2023 and 2022, respectively. As of December 31, 2023, we had an accumulated deficit of $477.3 million. Should we resume development of our product candidates, we would expect to continue to incur significant expenses for at least the next several years as we advance our product candidates from preclinical development and clinical trials and seek regulatory approval of our product candidates. Should we resume development of our product candidates, we would expect to expend significant resources to advance these candidates. In addition, if we obtain marketing approval for any of our product candidates, we expect to incur significant commercialization expenses related to product manufacturing, marketing, sales and distribution.

Should we resume development of our product candidates, we would need substantial 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 would expect to finance our operations with proceeds from outside sources, with a majority of such proceeds expected to be derived from sales of equity. We may also pursue additional funding from outside sources, including borrowing arrangements and entry into potential future collaboration agreements for one or more of our programs. We may be unable to raise additional funds or enter into such other agreements or arrangements when needed on favorable terms, or at all.

Because of the numerous risks and uncertainties associated with product development, we are unable to predict the timing or amount of increased expenses or when or if we will be able to achieve or maintain profitability, should we resume development of our product candidates. 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, we may be unable to continue our operations at planned levels and be forced to reduce or terminate our operations.

Components of Our Consolidated Results of Operations

Operating Expenses

Research and Development Expenses

Research and development expenses consist primarily of costs incurred in connection with the discovery and development of our product candidates. We expense research and development costs as incurred. These expenses consist of costs incurred in connection with the development of our product candidates, including:

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license maintenance fees and milestone fees incurred in connection with various license agreements;

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expenses incurred under agreements with CROs, CMOs, as well as investigative sites and consultants that conduct our clinical trials, preclinical studies and other scientific development services;

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•
manufacturing scale-up expenses and the cost of acquiring and manufacturing preclinical and clinical trial materials and commercial materials, including manufacturing validation batches;

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costs of purchasing lab supplies and non‑capital equipment used in our preclinical activities;

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employee-related expenses, including salaries, related benefits, travel and stock-based compensation expense for employees engaged in research and development functions;

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costs related to compliance with regulatory requirements; and

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allocated facilities costs, depreciation and other expenses, which include rent and utilities.

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.

Our direct research and development expenses are tracked on a program-by-program basis for our product candidates and consist primarily of external costs, such as fees paid to outside consultants, CROs, CMOs, and central laboratories in connection with our preclinical development, process development, manufacturing and clinical development activities. Our direct research and development expenses by program also include fees incurred under license agreements. We do not allocate employee costs or facility expenses, including depreciation or other indirect costs, to specific programs because these costs are deployed across multiple programs and, as such, are not separately classified. We use internal resources primarily to oversee the research and discovery as well as for managing our preclinical development, process development, manufacturing and clinical development activities. These employees work across multiple programs and, therefore, we do not track their costs by program.

The table below summarizes our research and development expenses related to our product candidates (in thousands):

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. Should we resume development of our product candidates, we would expect our research and development expenses to increase substantially over the next several years, particularly as we increase personnel costs, including stock-based compensation, contractor costs and facilities costs, and advance the development of our product candidates. Should we resume development of our product candidates, we would also expect to incur additional expenses related to milestone and royalty payments payable to third parties with whom we have entered into license agreements to acquire the rights to our product candidates.

The successful development and commercialization of our product candidates is highly uncertain. At this time, we cannot reasonably estimate or know the nature, timing and costs of the efforts that will be necessary to complete the preclinical and clinical development of any of our product candidates should we resume their development, or when, if ever, material net cash inflows may commence from any of our product candidates. This uncertainty is due to the numerous risks and uncertainties associated with product development and commercialization, including the uncertainty of:

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the scope, progress, outcome and costs of our preclinical development activities, clinical trials and other research and development activities;

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establishing an appropriate safety profile with IND-enabling studies;

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successful patient enrollment in, and the design, initiation and completion of, clinical trials;

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the timing, receipt and terms of any marketing approvals from applicable regulatory authorities;

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•
establishing commercial manufacturing capabilities or making arrangements with third-party manufacturers;

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development and timely delivery of commercial-grade drug formulations that can be used in our clinical trials and for commercial launch;

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obtaining, maintaining, defending and enforcing patent claims and other intellectual property rights;

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significant and changing government regulation;

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launching commercial sales of our product candidates, if and when approved, whether alone or in collaboration with others;

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maintaining a continued acceptable safety profile of the product candidates following approval; and

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the risks disclosed in the section entitled “Risk Factors” of this Annual Report on Form 10-K.

Should we resume development of our product candidates, we may never succeed in achieving regulatory approval for any of our product candidates. We may obtain unexpected results from our clinical trials. We may elect to discontinue, delay or modify clinical trials of some product candidates or focus on others. Any changes in the outcome of any of these variables with respect to the development of our product candidates in preclinical and clinical development could mean a significant change in the costs and timing associated with the development of these product candidates. For example, if the FDA, or another regulatory authority were to delay our planned start of clinical trials or require us to conduct clinical trials or other testing beyond those that we currently expect, or if we experience significant delays in enrollment in any of our planned clinical trials, we could be required to expend significant additional financial resources and time on the completion of clinical development of that product candidate. Identifying potential product candidates and conducting preclinical testing 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 and achieve product sales. In addition, our product candidates, if approved, may not achieve commercial success.

General and Administrative Expenses

General and administrative expenses consist primarily of salaries, related benefits, travel and stock-based compensation expense for personnel in executive, finance and administrative functions. General and administrative expenses also include professional fees for legal, consulting, accounting and audit services.

Should we resume development of our product candidates, we would anticipate that our general and administrative expenses would increase as we increase our headcount to support research activities and development of our product candidates. We also anticipate that we would incur increased accounting, audit, legal, compliance, director and officer insurance costs as well as investor and public relations expenses associated with being a public company. We anticipate the additional costs for these services would substantially increase our general and administrative expenses. Additionally, if and when we believe a regulatory approval of a product candidate appears likely, we anticipate an increase in payroll and other commercialization-related expenses as a result of our preparation for commercial operations, especially as it relates to the sales and marketing of our product candidate.

Other Income (Expense), Net

Other (expense) income, net primarily consists of interest income earned on our cash and cash equivalents, changes in foreign currency, and interest expense related to our prior Term Loan Agreement.

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Consolidated Results of Operations

Comparison of the Years Ended December 31, 2023 and 2022

The following table summarizes our consolidated results of operations (in thousands):

Research and Development Expenses

Research and development expenses decreased by $24.5 million to $47.7 million for the year ended December 31, 2023, from approximately $72.2 million for the year ended December 31, 2022. This decrease was driven by a $12.3 million decrease in personnel-related and consulting costs, including non-cash stock-based compensation, a $7.8 million decrease in manufacturing costs, a $2.5 million decrease in preclinical costs, a $1.5 million decrease in allocated facility expense, and a $0.3 million decrease in development costs, which includes a payment made in connection with the termination of the MPSII License Agreement.

General and Administrative Expenses

General and administrative expenses decreased by $9.3 million to $24.0 million for the year ended December 31, 2023, from $33.2 million for the year ended December 31, 2022. This decrease was driven by a $10.8 million decrease in personnel-related and consulting costs, including non-cash stock-based compensation and a $0.9 million decrease in information technology-related costs which was partially offset by a $2.4 million increase in legal expenses.

Gain on Asset Sale

For the year ended December 31, 2023 we recognized $83.7 million as a gain on asset sale, net of $3.8 million in transaction costs. We completed the Asset Sale on June 9, 2023.

Loss on Impairment

For the year ended December 31, 2023 we recognized a $1.9 million loss on impairment. Of this amount, $0.9 million is related to the loss on impairment of property, plant, and equipment as a result of the reclassification of these assets to held for sale. In addition, $0.9 million is related to the loss on impairment of the right of use asset for the subleased lab space located in Cambridge, Massachusetts, which is no longer in use.

Other Income (Expense), Net

Other income (expense), net was $2.3 million for the year ended December 31, 2023, compared to $(0.5) million of other income (expense), net for the year ended December 31, 2022. The increase in income was driven by a $2.8 million increase in interest income earned on short-term money market funds. Interest expense is relatively consistent period over

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period. The Term Loan Agreement was terminated in the second quarter of 2023 which resulted in an increase in interest expense from the loss on the extinguishment of debt due to the write-off of the debt discount balance.

Provision for Income Tax Expense

For the year ended December 31, 2023 we recognized $0.4 million as a provision for income tax expense as a result of income recognized from the Asset Sale.

Liquidity and Capital Resources

Since our inception, we have not generated any revenue and have incurred significant operating losses and negative cash flows from our operations. We have funded our operations to date primarily with proceeds from the sale of preferred stock and our common stock through our IPO, and we have raised additional capital through subsequent follow-on offerings and our prior ATM facility. Through December 31, 2023, we had received gross cash proceeds of $87.5 million from sales of our preferred stock; gross cash proceeds, before deducting underwriting discounts and commissions and expenses, of $428.1 million from sales of our common stock through our IPO and follow-on offerings; gross cash proceeds, before deducting commissions and expenses, of $23.5 million from sales of our common stock under our prior ATM facility; $15.0 million drawn in term loans under our Term Loan Agreement, which was repaid in full and terminated on June 9, 2023; and gross proceeds, before deducting transaction costs, of $87.5 million from the sale of our cystinosis gene therapy program.

On July 1, 2019, we filed a shelf registration statement on Form S-3 with the SEC, or the July 2019 Shelf, which covers the offering, issuance and sale by us of up to an aggregate of $200.0 million of our common stock, preferred stock, debt securities, warrants and/or units. We simultaneously entered into a Sales Agreement with Cowen and Company, LLC, as sales agent, to provide for the offering, issuance and sale by us of up to $50.0 million of our common stock from time to time in ATM offerings under the July 2019 Shelf. The July 2019 Shelf was declared effective by the SEC on July 10, 2019.

On December 20, 2019, we filed a shelf registration statement on Form S-3 with the SEC, or the December 2019 Shelf, which covers the offering, issuance and sale by us of up to an aggregate of $250.0 million of our common stock, preferred stock, debt securities, warrants and/or units. The December 2019 Shelf was declared effective by the SEC on January 14, 2020.

In July 2019, we closed an underwritten public offering, or the July 2019 Follow-On Offering, under the July 2019 Shelf of 7,475,000 shares of our common stock at a public offering price of $18.50 per share, which included 975,000 shares of our common stock resulting from the full exercise of the underwriters’ option to purchase additional shares at the public offering price. The net proceeds to us from this offering, after deducting underwriting discounts and commissions and other offering expenses payable by us, were $129.5 million.

In February 2020, we closed an underwritten public offering, or the February 2020 Follow-On Offering, under the December 2019 Shelf of 4,350,000 shares of our common stock at a public offering price of $23.00 per share. The net proceeds to us from this offering, after deducting underwriting discounts and commissions and other offering expenses payable by us, were $93.6 million.

In June 2020, we sold an aggregate of 384,140 shares of common stock under the prior ATM facility for net proceeds, after deducting commissions and other offering expenses payable by us, of $8.1 million.

In November 2020, we closed an underwritten public offering, or the November 2020 Follow-On Offering, of 5,000,000 shares of our common stock at a public offering price of $15.00 per share. The net proceeds to us from the November 2020 Follow-On Offering, after deducting underwriting discounts and commissions and other offering expenses payable by us, were $70.2 million.

In May 2021, we sold an aggregate of 1,829,268 shares of common stock under the prior ATM facility for net proceeds, after deducting commissions and other offering expenses payable by us, of $14.5 million. As of September 30, 2023, approximately $26.5 million of common stock remained available for future issuance under the prior ATM facility.

On November 2, 2021, or the Closing Date, we entered into the Term Loan Agreement. The Term Loan Agreement provided for (i) on the Closing Date, $30.0 million aggregate principal amount of term loans available through October 31, 2023; (ii) an additional $20.0 million in term loan facilities available through October 31, 2023 upon the achievement of certain regulatory or clinical milestones prior to the time of draw, or the Milestone Funding; and (iii) an additional

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discretionary $15.0 million term loan facility available upon our request and approval by the Agent and the Lenders, or, collectively, the Term Loans. We drew $15.0 million in term loans on the Closing Date. On June 9, 2023, upon the closing of the Asset Sale, all outstanding amounts due and owed, including principal, interest, and other charges, under the Term Loan Agreement, dated as of November 2, 2021, by and among the Company, Silicon Valley Bank, a division of First-Citizens Bank & Trust and the other parties thereto, were repaid in full and the Term Loan Facility was terminated. Upon repayment, the obligations of the Company under the Term Loan Facility were satisfied in full, the Term Loan Facility and all related loan documents were terminated and all liens and security interests granted thereunder were released and terminated (excluding certain indemnification obligations that expressly survive termination of the Term Loan Facility).

In July 2022, the July 2019 Shelf expired, and on November 8, 2022, we filed a shelf registration statement on Form S-3 with the SEC, or the November 2022 Shelf, which covered the offering, issuance and sale by us of up to an aggregate of $250.0 million of our common stock, preferred stock, debt securities, warrants and/or units. The December 2019 Shelf expired in December 2022, and the November 2022 Shelf carried forward unsold securities previously covered by the December 2019 Shelf, thus registering an aggregate total of $250.0 million of our common stock, preferred stock, debt securities, warrants and/or units. In connection with the November 2022 Shelf, we simultaneously entered into a new Sales Agreement with Cowen and Company, LLC, as sales agent, to provide for the offering, issuance and sale by us of up to $50.0 million of our common stock from time to time in “at-the-market” offerings under the November 2022 Shelf, or the 2022 ATM Facility. As of the date of this report, we have not made any sales under the 2022 ATM Facility. On November 3, 2023, we withdrew the November 2022 Shelf. We will not make any potential sales under the 2022 ATM Facility unless a new shelf registration statement on Form S-3 is filed and declared effective.

As of December 31, 2023, we had cash and cash equivalents of $98.0 million. Cash in excess of immediate requirements is invested primarily with a view to liquidity and capital preservation.

Our material cash requirements include contractual obligations with third parties. We have non-cancelable operating leases for office and laboratory space, which are located in Cambridge, Massachusetts and will expire in April 2024. As of December 31, 2023, we expect our future minimum lease payments under this commitment to total approximately $0.9 million in 2024. These minimum lease payments do not include any related common area maintenance charges or real estate taxes.

We enter into contracts in the normal course of business with CROs, CMOs and other third parties for clinical trials, preclinical research studies and testing and manufacturing services. Payments due upon cancellation consist only of payments for services provided or expenses incurred, including noncancelable obligations of our service providers, up to the date of cancellation. These payments are not included above as the amount and timing of such payments are not known.

In addition, pursuant to our current or former license agreements with UHN, BioMarin, The University of Manchester, Papillon and the Lund University rights holders, we are or were required to make certain milestone and royalty payments to our licensors. See “Business—License Agreements” for additional details regarding our payment obligations to these licensors.

Cash Flows

The following table summarizes our cash flows for each of the periods presented (in thousands):

Operating Activities

During the year ended December 31, 2023, operating activities used $63.2 million of cash and cash equivalents, resulting from our net income of $12.2 million, including gain on asset sale of $83.7 million, which was offset by the gain on asset sale that is classified as investing activities, net non-cash charges of $12.7 million and changes in our operating assets

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and liabilities of $4.3 million. Net cash used by changes in our operating assets and liabilities for the year ended December 31, 2023 was primarily due to a $6.7 million decrease in accrued expenses and other current liabilities and a $2.5 million decrease in current and non-current operating lease liabilities, partially offset by a $5.2 million decrease in prepaids and other current assets. The non-cash charges included $6.9 million of stock-based compensation expense, $1.9 million in non-cash asset impairment charges, $1.1 million in non-cash interest expense, $1.9 million in non-cash lease expense, and $0.6 million in depreciation and amortization expense.

During the year ended December 31, 2022, operating activities used $97.2 million of cash and cash equivalents, resulting from our net loss of $(105.9) million and cash used by changes in our operating assets and liabilities of $7.4 million which was offset by non-cash charges of $16.1 million. Net cash used by changes in our operating assets and liabilities for the year ended December 31, 2022 consists primarily of a $2.5 million decrease in prepaid expenses and other current assets, a $3.9 million decrease in accrued expenses and other current liabilities, a $3.1 million decrease in accounts payable, and a $2.9 million decrease in current and non-current operating lease liabilities. The increase in accrued expenses and other current liabilities was primarily due to an increase in accrued compensation and benefit costs.

Investing Activities

Net cash provided by (used in) investing activities was $85.1 million for the year ended December 31, 2023 compared to $(0.3) million for the year ended December 31, 2022. The increase in cash provided by investing activities is related to the net proceeds received for the sale of the cystinosis program in the second quarter of 2023 for proceeds net of transaction costs of $83.7 million, and $1.4 million in proceeds from the sale of property, plant, and equipment.

Financing Activities

Net cash used by financing activities was $16.0 million for the year ended December 31, 2023 compared to net cash provided by financing activities of $0.3 million for the year ended December 31, 2022. The change is related to the repayment of the Term Loan Agreement in the second quarter of 2023.

Funding Requirements

Should we resume development of our product candidates, we would expect our expenses to increase substantially in connection with such activities, particularly with respect to preclinical activities and clinical trials of our product candidates. Our expenses would also increase should we:

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continue our development of our product candidates, including enrollment and dosing of patients in clinical trials;

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initiate clinical trials and preclinical studies for product candidates;

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seek to identify and develop or in-license or acquire additional product candidates and technologies;

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seek to industrialize our HSC gene therapy approach into a robust, scalable and, if approved, commercially viable process;

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

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

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hire and retain additional personnel, such as clinical, quality control, and scientific personnel;

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expand our infrastructure, office space and facilities to accommodate our employee base, including adding equipment and physical infrastructure to support our research and development; and

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continue to incur additional public company-related costs.

Until such time, if ever, that we can generate product revenue sufficient to achieve profitability, we expect to finance our cash needs through a combination of equity offerings, debt financings, collaboration agreements, government and other third-party funding, strategic alliances, licensing arrangements or marketing and distribution arrangements. Debt financing and preferred equity financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends. If we raise additional funds through government and other third-party funding, collaboration agreements, strategic alliances, licensing arrangements or marketing and distribution arrangements, we may have to relinquish valuable rights to our technologies,

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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 when needed, we may be required to delay, limit, reduce or terminate our product development or future commercialization efforts or grant rights to develop and market products or product candidates that we would otherwise prefer to develop and market ourselves.

Critical Accounting Policies and Significant Judgments and Estimates

Our consolidated financial statements are prepared in accordance with GAAP principles in the United States. The preparation of our consolidated financial statements and related disclosures requires us to make estimates and judgments that affect the reported amounts of assets, liabilities, revenue, costs and expenses, and the disclosure of contingent assets and liabilities in our 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 more detail in Note 2 “Summary of Significant Accounting Policies” to our consolidated financial statements appearing elsewhere in this Annual Report, 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. We periodically confirm the accuracy of these estimates with the service providers and make adjustments if necessary. Examples of estimated accrued research and development expenses include fees paid to:

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vendors, including central laboratories, in connection with preclinical development activities;

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CROs and investigative sites in connection with preclinical and clinical studies; and

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CMOs in connection with drug substance and drug product formulation of preclinical and clinical trial materials.

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 research institutions and CROs that 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

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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 measure stock options and other stock-based awards granted to employees and members of our board of directors for their services as directors based on the fair value on the date of the grant and recognize the corresponding compensation expense of those awards over the requisite service period, which is generally the vesting period of the respective award. We have issued stock options, restricted stock and RSUs with service-based vesting conditions.

Modifications to stock-based awards are treated as an exchange of the original award for a new award with total compensation equal to the grant-date fair value of the original award plus any incremental value of the modification. The incremental value is based on the excess of the fair value of the modified award over the fair value of the original award immediately before the modification.

Prior to the adoption of Accounting Standards Update (ASU) No. 2018-07, Compensation—Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting (ASU 2018-07), as discussed in Note 2 “Summary of Significant Accounting Policies” to our consolidated financial statements appearing elsewhere in this Annual Report, the measurement date for non-employee awards was generally the date the services were completed, resulting in financial reporting period adjustments to stock-based compensation during the vesting terms for changes in the fair value of the awards. After the adoption of ASU 2018-07, the measurement date for non-employee awards is the later of the adoption date of ASU 2018-07, or the date of grant, without change in the fair value of the award.

We estimate the fair value of each stock option grant using the Black-Scholes option-pricing model, which uses as inputs the estimated fair value of our common stock and assumptions we make for the volatility of our common stock, the expected term of our stock options, the risk-free interest rate for a period that approximates the expected term of our stock options and our expected dividend yield.

We determined the assumptions for the Black-Scholes option-pricing model as discussed below. Each of these inputs is subjective and generally requires significant judgment to determine.

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Determination of the Fair Value of Common Stock. The fair value of our common stock is determined based on the quoted market price of our common stock. Prior to our IPO, there was no public market for our common stock, and consequently, the estimated fair value of our common stock was determined by our board of directors as of the date of each option grant, with input from management, considering third-party valuations of our common stock as well as our board of directors’ assessment of additional objective and subjective factors that it believed were relevant and which may have changed from the date of the most recent third-party valuation through the date of the grant. These third-party valuations were performed in accordance with the guidance outlined in the American Institute of Certified Public Accountants’ Accounting and Valuation Guide, Valuation of Privately-Held-Company Equity Securities Issued as Compensation. Following the closing of our IPO, it was no longer necessary for our board of directors to estimate the fair market value of our common stock in connection with our accounting for granted equity awards.

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Expected Term. The expected term represents the period that the stock-based awards are expected to be outstanding. The expected term of stock options granted has been determined using the simplified method, which uses the midpoint between the vesting date and the contractual term.

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Risk-Free Interest Rate. The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the date of grant for zero-coupon U.S. Treasury constant maturity notes with terms approximately equal to the stock-based award’s expected term.

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Expected Volatility. Because we do not have long-term trading history of our common stock, the expected volatility was derived from the average historical stock volatilities of several public companies within our industry that we consider to be comparable to our business over a period equivalent to the expected term of the stock-based awards.

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Dividend Rate. The expected dividend is zero as we have not paid and do not anticipate paying any dividends in the foreseeable future.

If any of the assumptions used in the Black-Scholes model change significantly, stock-based compensation for future awards may differ materially compared with the awards granted previously.

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Off-Balance Sheet Arrangements

We did not have, during the periods presented, and we do not currently have, any off-balance sheet arrangements, as defined in the rules and regulations of the SEC.

Recently Issued Accounting Pronouncements

A description of recently issued accounting pronouncements that may potentially impact our financial position and results of operations is disclosed in Note 2 “Summary of Significant Accounting Policies” to our audited financial statements appearing elsewhere in this Annual Report on Form 10-K.

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Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

Our management’s discussion and analysis of our financial condition and results of operations are based upon our consolidated financial statements included in this Annual Report on Form 10-K, which have been prepared by us in accordance with United States generally accepted accounting principles, or GAAP, and with Regulation S-X promulgated under the Securities Exchange Act of 1934, as amended. This discussion and analysis should be read in conjunction with the consolidated financial statements and the notes thereto included elsewhere in this Annual Report on Form 10-K. Some of the information 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, includes forward-looking statements that involve risks and uncertainties. As a result of many factors, including those factors set forth in Part I, Item 1A. Risk Factors of this Annual Report on Form 10-K, our actual results could differ materially from the results described in or implied by the forward-looking statements contained in the following discussion and analysis.

Overview

We are a clinical-stage gene therapy company with a purpose to free people from a lifetime of genetic disease. Our company is focused on developing potentially curative HSC gene therapies to treat patients with rare diseases following a single dose treatment regimen. Our gene therapies employ HSCs that are harvested from the patient and then modified with a lentiviral vector to insert the equivalent of a functional copy of the gene that is mutated in the target disease. We believe that our approach, which is designed to transform stem cells from patients into therapeutic products, has the potential to provide curative benefit for a range of diseases. Our initial focus is on a group of rare genetic diseases referred to as lysosomal disorders, some of which today are primarily managed with enzyme replacement therapies, or ERTs. These lysosomal disorders have well-understood biologies, identified patient populations, established standards of care yet with significant unmet needs, and represent large market opportunities with approximately $3.5 billion in worldwide net sales in 2022.

Our pipeline is comprised of four HSC gene therapy programs: AVR-RD-02 for the treatment of Gaucher disease type 1 and type 3; AVR-RD-04 for the treatment of cystinosis; AVR-RD-05 for the treatment of neuronopathic mucopolysaccharidosis type II, or MPS-II or Hunter syndrome; and AVR-RD-03 for the treatment of Pompe disease.

AVR-RD-02 is currently being studied for the treatment of Gaucher disease type 1 in a Company-sponsored Phase 1/2 clinical trial, which we refer to as the Guard1 clinical trial. As of March 20, 2023, four patients have been dosed in the Guard1 clinical trial, and six patients have been enrolled. We are actively recruiting additional potential patients for our currently active Guard1 trial sites. We are also planning for a registrational global Phase 2/3 clinical trial of AVR-RD-02 for the treatment of Gaucher disease type 3, which we refer to as the Guard3 clinical trial. We currently are planning for the Guard3 clinical trial to be initiated in the second half of 2023, subject to regulatory alignment.

AVR-RD-04 is currently being studied for the treatment of cystinosis by our collaborators at UCSD in a Phase 1/2 collaborator-sponsored clinical trial. Enrollment of this clinical trial is complete with a total of six patients dosed. In addition, based on recent regulatory interactions and feedback and subject to regulatory clearance, we are planning to initiate activities for a Company-sponsored Phase 1/2 clinical trial of AVR-RD-04 for the treatment of cystinosis in the second half of 2023, which is designed to be registration-enabling.

AVR-RD-05 is being studied for the treatment of Hunter syndrome by our collaborators at The University of Manchester, and we currently expect the Phase 1/2 collaborator-sponsored clinical trial will be initiated in 2023.

AVR-RD-03 is our preclinical program for Pompe disease. While we continue to advance AVR-RD-03, we are prioritizing our Gaucher disease and cystinosis clinical programs. As a result, we no longer expect to initiate a clinical trial for AVR-RD-03 in 2023.

In January 2022, we announced the deprioritization of AVR-RD-01, our investigational gene therapy program for Fabry disease. This decision was made due to several factors, including new clinical data showing variable engraftment patterns from the five most recently dosed patients in the Company’s Phase 2 clinical trial of AVR-RD-01 for the treatment of Fabry disease, which we refer to as the FAB-GT clinical trial. As a result of the deprioritization, the Company stopped enrollment of its Phase 2 FAB-GT clinical trial and continues to focus on its other pipeline programs.

Since our inception in 2015, we have devoted substantially all of our resources to organizing and staffing our company, business planning, raising capital, acquiring or discovering product candidates and securing related intellectual property rights, conducting discovery, research and development activities for our programs and planning for potential commercialization. To date, we have not generated any product revenue and have financed our operations primarily through

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the private placement of our securities and through public offerings of our common stock. Through December 31, 2022, we had received gross cash proceeds of $87.5 million from sales of our preferred stock; gross cash proceeds, before deducting underwriting discounts and commissions and expenses, of $428.1 million from sales of our common stock through our initial public offering and follow-on offerings; and gross cash proceeds, before deducting commissions and expenses, of $23.5 million from sales of our common stock through our 2019 “at-the-market” facility, or 2019 ATM Facility.

Additionally, we have incurred significant operating losses. Our ability to generate product revenue sufficient to achieve profitability will depend heavily on the successful development and eventual commercialization of one or more of our current or future product candidates and programs. Our net losses were $105.9 million and $119.1 million for the years ended December 31, 2022 and 2021, respectively. As of December 31, 2022, we had an accumulated deficit of $489.4 million. We expect to continue to incur significant expenses for at least the next several years as we advance our current and future product candidates from discovery through preclinical development and clinical trials and seek regulatory approval of our product candidates. Our pipeline consists of four investigational gene therapies, two of which are currently in clinical development. As a result, further development of these programs will require us to expend significant resources to advance these candidates. In addition, if we obtain marketing approval for any of our product candidates, we expect to incur significant commercialization expenses related to product manufacturing, marketing, sales and distribution. We may also incur expenses in connection with the in-licensing or acquisition of additional product candidates.

We will need substantial 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 with proceeds from outside sources, with a majority of such proceeds to be derived from sales of equity, including the net proceeds from our follow-on offerings and sales of common stock under our 2019 ATM Facility as well as proceeds under our Term Loan Agreement. We may also pursue additional funding from outside sources, including our expansion of, or our entry into, new borrowing arrangements; research and development incentive payments from the Australian government; and our entry into potential future collaboration agreements for one or more of our programs. 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 or delay our pursuit of potential in-licenses or acquisitions.

Because of the numerous risks and uncertainties associated with product development, we are unable to 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, we may be unable to continue our operations at planned levels and be forced to reduce or terminate our operations.

As of December 31, 2022, we had cash and cash equivalents of $92.6 million. We believe that our existing cash and cash equivalents as of December 31, 2022 will enable us to fund our operating expenses and capital expenditure requirements into the first quarter of 2024. We have based this estimate on assumptions that may prove to be wrong, and we could exhaust our available capital resources sooner than we expect. See “Liquidity and Capital Resources.” To finance our operations beyond that point, we will need to raise additional capital, which cannot be assured.

Components of Our Consolidated Results of Operations

Operating Expenses

Research and Development Expenses

Research and development expenses consist primarily of costs incurred in connection with the discovery and development of our product candidates. We expense research and development costs as incurred. These expenses consist of costs incurred in connection with the development of our product candidates, including:

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license maintenance fees and milestone fees incurred in connection with various license agreements;

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expenses incurred under agreements with contract research organizations, or CROs, contract manufacturing organizations, or CMOs, as well as investigative sites and consultants that conduct our clinical trials, preclinical studies and other scientific development services;

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manufacturing scale-up expenses and the cost of acquiring and manufacturing preclinical and clinical trial materials and commercial materials, including manufacturing validation batches;

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costs of purchasing lab supplies and non‑capital equipment used in our preclinical activities;

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employee-related expenses, including salaries, related benefits, travel and stock-based compensation expense for employees engaged in research and development functions;

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costs related to compliance with regulatory requirements; and

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allocated facilities costs, depreciation and other expenses, which include rent and utilities.

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.

Our direct research and development expenses are tracked on a program-by-program basis for our product candidates and consist primarily of external costs, such as fees paid to outside consultants, CROs, CMOs, and central laboratories in connection with our preclinical development, process development, manufacturing and clinical development activities. Our direct research and development expenses by program also include fees incurred under license agreements. We do not allocate employee costs or facility expenses, including depreciation or other indirect costs, to specific programs because these costs are deployed across multiple programs and, as such, are not separately classified. We use internal resources primarily to oversee the research and discovery as well as for managing our preclinical development, process development, manufacturing and clinical development activities. These employees work across multiple programs and, therefore, we do not track their costs by program.

The table below summarizes our research and development expenses related to our product candidates (in thousands):

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. As a result, we expect that our research and development expenses will increase substantially over the next several years, particularly as we increase personnel costs, including stock-based compensation, contractor costs and facilities costs, as we continue to advance the development of our product candidates. We also expect to incur additional expenses related to milestone and royalty payments payable to third parties with whom we have entered into license agreements to acquire the rights to our product candidates.

The successful development and commercialization of our product candidates is highly uncertain. At this time, we cannot reasonably estimate or know the nature, timing and costs of the efforts that will be necessary to complete the preclinical and clinical development of any of our product candidates or when, if ever, material net cash inflows may commence from any of our product candidates. This uncertainty is due to the numerous risks and uncertainties associated with product development and commercialization, including the uncertainty of:

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the scope, progress, outcome and costs of our preclinical development activities, clinical trials and other research and development activities;

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establishing an appropriate safety profile with IND-enabling studies;

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successful patient enrollment in, and the design, initiation and completion of, clinical trials;

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the timing, receipt and terms of any marketing approvals from applicable regulatory authorities;

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establishing commercial manufacturing capabilities or making arrangements with third-party manufacturers;

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•
development and timely delivery of commercial-grade drug formulations that can be used in our clinical trials and for commercial launch;

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obtaining, maintaining, defending and enforcing patent claims and other intellectual property rights;

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significant and changing government regulation;

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launching commercial sales of our product candidates, if and when approved, whether alone or in collaboration with others;

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maintaining a continued acceptable safety profile of the product candidates following approval; and

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the risks disclosed in the section entitled “Risk Factors” of this Annual Report on Form 10-K.

We may never succeed in achieving regulatory approval for any of our product candidates. We may obtain unexpected results from our clinical trials. We may elect to discontinue, delay or modify clinical trials of some product candidates or focus on others. Any changes in the outcome of any of these variables with respect to the development of our product candidates in preclinical and clinical development could mean a significant change in the costs and timing associated with the development of these product candidates. For example, if the FDA, or another regulatory authority were to delay our planned start of clinical trials or require us to conduct clinical trials or other testing beyond those that we currently expect, or if we experience significant delays in enrollment in any of our planned clinical trials, we could be required to expend significant additional financial resources and time on the completion of clinical development of that product candidate. Identifying potential product candidates and conducting preclinical testing 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 and achieve product sales. In addition, our product candidates, if approved, may not achieve commercial success.

General and Administrative Expenses

General and administrative expenses consist primarily of salaries, related benefits, travel and stock-based compensation expense for personnel in executive, finance and administrative functions. General and administrative expenses also include professional fees for legal, consulting, accounting and audit services.

We anticipate that our general and administrative expenses will increase in the future as we increase our headcount to support our continued research activities and development of our product candidates. We also anticipate that we will continue to incur increased accounting, audit, legal, compliance, director and officer insurance costs as well as investor and public relations expenses associated with being a public company. We anticipate the additional costs for these services will substantially increase our general and administrative expenses. Additionally, if and when we believe a regulatory approval of a product candidate appears likely, we anticipate an increase in payroll and other commercialization-related expenses as a result of our preparation for commercial operations, especially as it relates to the sales and marketing of our product candidate.

Other (Expense) Income, net

Other (expense) income, net primarily consists of interest income earned on our cash and cash equivalents, changes in foreign currency, and interest expense related to our Term Loan Agreement.

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Consolidated Results of Operations

Comparison of the Years Ended December 31, 2022 and 2021

The following table summarizes our consolidated results of operations (in thousands):

Research and Development Expenses

Research and development expenses decreased by $10.9 million to $72.2 million for the year ended December 31, 2022, from approximately $83.1 million for the year ended December 31, 2021. This decrease was driven by a $9.7 million decrease in personnel-related costs which was impacted by our reduction in workforce implemented in January 2022, a $2.6 million decrease in our preclinical costs, and a $1.6 million decrease in manufacturing costs. These decreases were partially offset by a $2.1 million increase in development costs and a $0.8 million increase in consulting costs.

General and Administrative Expenses

General and administrative expenses decreased by $2.5 million to $33.2 million for the year ended December 31, 2022, from $35.7 million for the year ended December 31, 2021. This decrease was attributable to $1.8 million decrease in personnel-related costs which was impacted by our reduction in workforce implemented in January 2022 and a $0.7 million decrease in professional fees.

Other (Expense) Income, net

Other (expense) income, net was $(0.5) million for the year ended December 31, 2022, compared to $(0.3) million of other income, net for the year ended December 31, 2021. The increase in expense was driven by a $1.6 million increase in interest expense related to our Term Loan Agreement, which we entered into in the fourth quarter of 2021 and partially offset by a $1.5 million increase in interest income earned on short-term money market funds.

Liquidity and Capital Resources

Since our inception, we have not generated any revenue and have incurred significant operating losses and negative cash flows from our operations. We have funded our operations to date primarily with proceeds from the sale of preferred stock and our common stock through our initial public offering, or IPO, and we have raised additional capital through subsequent follow-on offerings and our 2019 ATM Facility, as well as through our Term Loan Agreement. Through December 31, 2022, we had received gross cash proceeds of $87.5 million from sales of our preferred stock; gross cash proceeds, before deducting underwriting discounts and commissions and expenses, of $428.1 million from sales of our common stock through our IPO and follow-on public offerings; $23.5 million in gross proceeds from the sale of our common stock under our 2019 ATM Facility; and we had drawn $15.0 million in term loans under our Term Loan Agreement.

On July 1, 2019, we filed a shelf registration statement on Form S-3 with the SEC, or the July 2019 Shelf, which covers the offering, issuance and sale by us of up to an aggregate of $200.0 million of our common stock, preferred stock, debt securities, warrants and/or units. We simultaneously entered into a Sales Agreement with Cowen and Company, LLC, as sales agent, to provide for the offering, issuance and sale by us of up to $50.0 million of our common stock from time to time in “at-the-market” offerings under the July 2019 Shelf. The July 2019 Shelf was declared effective by the SEC on July 10, 2019.

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On December 20, 2019, we filed a shelf registration statement on Form S-3 with the SEC, or the December 2019 Shelf, which covers the offering, issuance and sale by us of up to an aggregate of $250.0 million of our common stock, preferred stock, debt securities, warrants and/or units. The December 2019 Shelf was declared effective by the SEC on January 14, 2020.

In July 2019, we closed an underwritten public offering, or the July 2019 Follow-On Offering, under the July 2019 Shelf of 7,475,000 shares of our common stock at a public offering price of $18.50 per share, which included 975,000 shares of our common stock resulting from the full exercise of the underwriters’ option to purchase additional shares at the public offering price, less underwriting discounts and commissions. The net proceeds to us from this offering, after deducting underwriting discounts and commissions and other offering expenses payable by us, were $129.5 million.

In February 2020, we closed an underwritten public offering, or the February 2020 Follow-On Offering, under the December 2019 Shelf of 4,350,000 shares of our common stock at a public offering price of $23.00 per share, less underwriting discounts and commissions. The net proceeds to us from this offering, after deducting underwriting discounts and commissions and other offering expenses payable by us, were $93.6 million.

In June 2020, we sold an aggregate of 384,140 shares of common stock under the 2019 ATM Facility for net proceeds, after deducting commissions and other offering expenses payable by us, of $8.1 million.

In November 2020, we closed an underwritten public offering, or the November 2020 Follow-On Offering, of 5,000,000 shares of our common stock at a public offering price of $15.00 per share, less underwriting discounts and commissions. The net proceeds to us from the November 2020 Follow-On Offering, after deducting underwriting discounts and commissions and other offering expenses payable by us, were $70.2 million.

In May 2021, we sold an aggregate of 1,829,268 shares of common stock under the 2019 ATM Facility for net proceeds, after deducting commissions and other offering expenses payable by us, of $14.5 million. As of December 31, 2022, approximately $26.5 million of common stock remained available for future issuance under the 2019 ATM Facility.

On November 2, 2021, or the Closing Date, we entered into the Term Loan Agreement. The Term Loan Agreement provided for (i) on the Closing Date, $30.0 million aggregate principal amount of term loans available through October 31, 2023; (ii) an additional $20.0 million in term loan facilities available through October 31, 2023 upon the achievement of certain regulatory or clinical milestones prior to the time of draw, or the Milestone Funding; and (iii) an additional discretionary $15.0 million term loan facility available upon our request and approval by the Agent and the Lenders, or, collectively, the Term Loans. We drew $15.0 million in term loans on the Closing Date. As a result of the deprioritization of our Fabry disease program, we are no longer able to draw the $20.0 million of Milestone Funding per the terms of the Term Loan Agreement. The loan repayment schedule provides for interest only payments until November 1, 2024, followed by consecutive monthly payments of principal and interest. All unpaid principal and accrued and unpaid interest with respect to each term loan is due and payable in full on October 1, 2026.

In July 2022, the July 2019 Shelf expired, and on November 8, 2022, we filed a shelf registration statement on Form S-3 with the SEC, or the November 2022 Shelf, which covers the offering, issuance and sale by us of up to an aggregate of $250.0 million of our common stock, preferred stock, debt securities, warrants and/or units. The December 2019 Shelf expired in December 2022, and the November 2022 Shelf carried forward unsold securities previously covered by the December 2019 Shelf, thus registering an aggregate total of $250.0 million of our common stock, preferred stock, debt securities, warrants and/or units. Because the 2019 ATM Facility was established under the July 2019 Shelf that has expired, in connection with the November 2022 Shelf, we simultaneously entered into a new Sales Agreement with Cowen and Company, LLC, as sales agent, to provide for the offering, issuance and sale by us of up to $50.0 million of our common stock from time to time in “at-the-market” offerings under the November 2022 Shelf (the “2022 ATM Facility”). As of the date of this report, we have not made any sales under the 2022 ATM Facility, and intend to file one or more prospectuses or prospectus supplements related to this new facility before making any such sales.

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As of December 31, 2022, we had cash and cash equivalents of $92.6 million. Cash in excess of immediate requirements is invested primarily with a view to liquidity and capital preservation. We believe that our existing cash and cash equivalents as of December 31, 2022 will enable us to fund our operating expenses and capital expenditure requirements into the first quarter of 2024. See “Risk Factors” for risks related to our business, financial position and need for

additional capital.

Cash Flows

The following table summarizes our cash flows for each of the periods presented (in thousands):

Operating Activities

During the year ended December 31, 2022, operating activities used $97.2 million of cash and cash equivalents, resulting from our net loss of $105.9 million and cash used by changes in our operating assets and liabilities of $7.4 million which was offset by non-cash charges of $16.1 million. Net cash used by changes in our operating assets and liabilities for the year ended December 31, 2022 consists primarily of a $2.5 million decrease in prepaid expenses and other current assets, a $3.9 million decrease in accrued expenses and other current liabilities, a $3.1 million decrease in accounts payable, and a $2.9 million decrease in current and non-current operating lease liabilities. The increase in accrued expenses and other current liabilities was primarily due to an increase in accrued compensation and benefit costs.

During the year ended December 31, 2021, operating activities used $98.0 million of cash and cash equivalents, resulting from our net loss of $119.1 million, partially off-set by net cash provided by changes in our operating assets and liabilities of $1.3 million and non-cash charges of $19.8 million. Net cash provided by changes in our operating assets and liabilities for the year ended December 31, 2021 consists primarily of a $2.1 million increase in accrued expenses and other current liabilities, a $0.4 million decrease in other assets, and a $0.8 million increase in accounts payable, partially offset by a $2.0 million increase in prepaid expenses and other current assets. The increase in accrued expenses and other current liabilities was primarily due to an increase in accrued compensation and benefit costs.

Investing Activities

Net cash used in investing activities was $0.3 million for the year ended December 31, 2022 compared to $2.5 million for the year ended December 31, 2021. The decrease in cash used in investing activities was primarily due to a decrease in purchases of property and equipment.

Financing Activities

Net cash provided by financing activities was $0.3 million for the year ended December 31, 2022 compared to $30.4 million for the year ended December 31, 2021. The decrease in cash provided by financing activities was primarily due to the proceeds of $15.0 million from long-term debt, proceeds of $14.6 million from issuance of common shares under our 2019 ATM facility, net of offering costs paid, and $0.9 million from proceeds from the exercise of stock options during the year ended December 31, 2021 which was partially offset by $0.2 million in proceeds from the issuance of shares under our 2018 Employee Stock Purchase Plan and $0.1 million in proceeds from the exercise of stock options during the year ended December 31, 2022.

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Funding Requirements

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. Our expenses will also increase as we:

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continue our development of our product candidates, including enrollment and dosing of patients in our ongoing clinical trials;

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initiate additional clinical trials and preclinical studies for our other current and future product candidates;

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seek to identify and develop or in-license or acquire additional product candidates and technologies;

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seek to industrialize our HSC gene therapy approach into a robust, scalable and, if approved, commercially viable process;

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

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

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hire and retain additional personnel, such as clinical, quality control, and scientific personnel;

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expand our infrastructure, office space and facilities to accommodate our employee base, including adding equipment and physical infrastructure to support our research and development; and

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continue to incur additional public company-related costs.

We believe that our $92.6 million of existing cash and cash equivalents as of December 31, 2022, will enable us to fund our operating expenses and capital expenditure requirements into the first quarter of 2024. 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. If we receive regulatory approval for any of our product candidates, we expect to incur significant commercialization expenses related to product manufacturing, sales, marketing and distribution, depending on where we choose to commercialize.

Until such time, if ever, that we can generate product revenue sufficient to achieve profitability, we expect to finance our cash needs through a combination of equity offerings, debt financings, collaboration agreements, government and other third-party funding, strategic alliances, licensing arrangements or marketing and distribution arrangements. Debt financing and preferred equity financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends. If we raise additional funds through government and other third-party funding, collaboration agreements, strategic alliances, licensing arrangements or marketing and distribution arrangements, we may have to relinquish valuable rights to our technologies, 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 when needed, we may be required to delay, limit, reduce or terminate our product development or future commercialization efforts or grant rights to develop and market products or product candidates that we would otherwise prefer to develop and market ourselves.

Contractual Obligations and Commitments

The following table summarizes our contractual obligations as of December 31, 2022 and the effects that such obligations are expected to have on our liquidity and cash flows in future periods (in thousands):

(1) Represents future minimum lease payments under our non-cancelable operating leases for office and laboratory space, which are located in Cambridge, Massachusetts and Toronto, Canada. Those leases will expire from April 2024 to June 2025. The minimum lease payments above do not include any related common area maintenance charges or real estate taxes.

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We enter into contracts in the normal course of business with CROs, CMOs and other third parties for clinical trials, preclinical research studies and testing and manufacturing services. Payments due upon cancellation consist only of payments for services provided or expenses incurred, including noncancelable obligations of our service providers, up to the date of cancellation. These payments are not included in the preceding table as the amount and timing of such payments are not known.

In addition, pursuant to our license agreements with UHN, BioMarin, The University of Manchester, Papillon and the Lund University rights holders, we are required to make certain milestone and royalty payments to our licensors. See “Business—License Agreements” for additional details regarding our payment obligations to these licensors.

Critical Accounting Policies and Significant Judgments and Estimates

Our consolidated financial statements are prepared in accordance with GAAP principles in the United States. The preparation of our consolidated financial statements and related disclosures requires us to make estimates and judgments that affect the reported amounts of assets, liabilities, revenue, costs and expenses, and the disclosure of contingent assets and liabilities in our 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 more detail in Note 2 “Summary of Significant Accounting Policies” to our consolidated financial statements appearing elsewhere in this Annual Report, 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. We periodically confirm the accuracy of these estimates with the service providers and make adjustments if necessary. Examples of estimated accrued research and development expenses include fees paid to:

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vendors, including central laboratories, in connection with preclinical development activities;

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CROs and investigative sites in connection with preclinical and clinical studies; and

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CMOs in connection with drug substance and drug product formulation of preclinical and clinical trial materials.

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 research institutions and CROs that 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

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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 measure stock options and other stock-based awards granted to employees and members of our board of directors for their services as directors based on the fair value on the date of the grant and recognize the corresponding compensation expense of those awards over the requisite service period, which is generally the vesting period of the respective award. We have issued stock options, restricted stock and restricted stock units with service-based vesting conditions.

Modifications to stock-based awards are treated as an exchange of the original award for a new award with total compensation equal to the grant-date fair value of the original award plus any incremental value of the modification. The incremental value is based on the excess of the fair value of the modified award over the fair value of the original award immediately before the modification.

Prior to the adoption of Accounting Standards Update (ASU) No. 2018-07, Compensation—Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting (ASU 2018-07), as discussed in Note 2 “Summary of Significant Accounting Policies” to our consolidated financial statements appearing elsewhere in this Annual Report, the measurement date for non-employee awards was generally the date the services were completed, resulting in financial reporting period adjustments to stock-based compensation during the vesting terms for changes in the fair value of the awards. After the adoption of ASU 2018-07, the measurement date for non-employee awards is the later of the adoption date of ASU 2018-07, or the date of grant, without change in the fair value of the award.

We estimate the fair value of each stock option grant using the Black-Scholes option-pricing model, which uses as inputs the estimated fair value of our common stock and assumptions we make for the volatility of our common stock, the expected term of our stock options, the risk-free interest rate for a period that approximates the expected term of our stock options and our expected dividend yield.

We determined the assumptions for the Black-Scholes option-pricing model as discussed below. Each of these inputs is subjective and generally requires significant judgment to determine.

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Determination of the Fair Value of Common Stock. The fair value of our common stock is determined based on the quoted market price of our common stock. Prior to our IPO, there was no public market for our common stock, and consequently, the estimated fair value of our common stock was determined by our board of directors as of the date of each option grant, with input from management, considering third-party valuations of our common stock as well as our board of directors’ assessment of additional objective and subjective factors that it believed were relevant and which may have changed from the date of the most recent third-party valuation through the date of the grant. These third-party valuations were performed in accordance with the guidance outlined in the American Institute of Certified Public Accountants’ Accounting and Valuation Guide, Valuation of Privately-Held-Company Equity Securities Issued as Compensation. Following the closing of our IPO, it was no longer necessary for our board of directors to estimate the fair market value of our common stock in connection with our accounting for granted equity awards.

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Expected Term. The expected term represents the period that the stock-based awards are expected to be outstanding. The expected term of stock options granted has been determined using the simplified method, which uses the midpoint between the vesting date and the contractual term.

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Risk-Free Interest Rate. The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the date of grant for zero-coupon U.S. Treasury constant maturity notes with terms approximately equal to the stock-based award’s expected term.

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Expected Volatility. Because we do not have long-term trading history of our common stock, the expected volatility was derived from the average historical stock volatilities of several public companies within our industry that we consider to be comparable to our business over a period equivalent to the expected term of the stock-based awards.

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Dividend Rate. The expected dividend is zero as we have not paid and do not anticipate paying any dividends in the foreseeable future.

If any of the assumptions used in the Black-Scholes model change significantly, stock-based compensation for future awards may differ materially compared with the awards granted previously.

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Emerging Growth Company Status

We are an “emerging growth company,” as defined in the JOBS Act, and we may take advantage of certain exemptions from various reporting requirements that are applicable to other public companies that are not emerging growth companies. We may take advantage of these exemptions until we are no longer an emerging growth company. Section 107 of the JOBS Act provides that an emerging growth company can take advantage of the extended transition period afforded by the JOBS Act for the implementation of new or revised accounting standards. We have elected to use the extended transition period for complying with new or revised accounting standards and, as a result of this election, our financial statements may not be comparable to companies that comply with public company effective dates. We may take advantage of these exemptions up until the last day of the fiscal year following the fifth anniversary of our IPO or such earlier time that we are no longer an emerging growth company. We would cease to be an emerging growth company if we have more than $1.235 billion in annual revenue, we have more than $700.0 million in market value of our stock held by non-affiliates or we issue more than $1.0 billion of non-convertible debt securities over a three-year period.

Off-Balance Sheet Arrangements

We did not have, during the periods presented, and we do not currently have, any off-balance sheet arrangements, as defined in the rules and regulations of the Securities and Exchange Commission.

Recently Issued Accounting Pronouncements

A description of recently issued accounting pronouncements that may potentially impact our financial position and results of operations is disclosed in Note 2 “Summary of Significant Accounting Policies” to our audited financial statements appearing elsewhere in this Annual Report.

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Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

Our management’s discussion and analysis of our financial condition and results of operations are based upon our consolidated financial statements included in this Annual Report on Form 10-K, which have been prepared by us in accordance with United States generally accepted accounting principles, or GAAP, and with Regulation S-X promulgated under the Securities Exchange Act of 1934, as amended. This discussion and analysis should be read in conjunction with the consolidated financial statements and the notes thereto included elsewhere in this Annual Report on Form 10-K. Some of the information 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, includes forward-looking statements that involve risks and uncertainties. As a result of many factors, including those factors set forth in Part I, Item 1A. Risk Factors of this Annual Report on Form 10-K, our actual results could differ materially from the results described in or implied by the forward-looking statements contained in the following discussion and analysis.

Overview

We are a leading clinical-stage gene therapy company with a mission to free people from a lifetime of genetic disease.  Our company is focused on developing potentially curative ex vivo lentiviral-based gene therapies to treat patients with rare diseases following a single dose treatment regimen. Our gene therapies employ hematopoietic stem cells that are harvested from the patient and then modified with a lentiviral vector to insert the equivalent of a functional copy of the gene that is mutated in the target disease. We believe that our approach, which is designed to transform stem cells from patients into therapeutic products, has the potential to provide curative benefit for a range of diseases. Our initial focus is on a group of rare genetic diseases referred to as lysosomal disorders, some of which today are primarily managed with enzyme replacement therapies, or ERTs. These lysosomal disorders have well-understood biologies, identified patient populations, established standards of care yet with significant unmet needs, and represent large market opportunities with approximately $3.4 billion in worldwide net sales in 2021.

Our initial pipeline is comprised of five lentiviral-based gene therapy programs: AVR-RD-04 for the treatment of cystinosis; AVR-RD-02 for the treatment of Gaucher disease type 1; AVR-RD-05 for the treatment of Hunter syndrome; AVR-RD-06 for the treatment of Gaucher disease type 3; and AVR-RD-03 for the treatment of Pompe disease.

AVR-RD-04 is currently being studied for the treatment of cystinosis by our collaborators at the University of California, San Diego, or UCSD, in a Phase 1/2 collaborator-sponsored clinical trial, and as of March 1, 2022 four patients have been dosed. Three patients have been dosed as of March 1, 2022 in our Company-sponsored Phase 1/2 clinical trial of AVR-RD-02 for the treatment of Gaucher disease type 1, which we refer to as the Guard1 clinical trial, and we are actively recruiting additional potential patients for our currently active sites. AVR-RD-05 is being studied for the treatment of Hunter syndrome by our collaborators at The University of Manchester, and a Phase 1/2 investigator-sponsored clinical trial is expected to be initiated in 2023. AVR-RD-06 is our preclinical program for the treatment of Gaucher disease type 3, and we expect to engage with regulatory authorities this year to discuss a potential Phase 2/3 clinical trial. Our AVR-RD-03 program for Pompe disease has completed preclinical development, and we are planning to engage with regulatory authorities this year to discuss a potential path to the clinic with the goal of initiating a clinical trial in 2023. In January 2022 we announced the deprioritization of AVR-RD-01, our investigational gene therapy program for Fabry disease. This decision was made due to several factors, including new clinical data showing variable engraftment patterns from the five most recently dosed patients in the Company’s Phase 2 clinical trial of AVR-RD-01 for the treatment of Fabry disease, which we refer to as the FAB-GT clinical trial. As a result of the deprioritization, the Company has stopped enrollment of its Phase 2 FAB-GT clinical trial and will focus on its other pipeline programs.

Since our inception in 2015, we have devoted substantially all of our resources to organizing and staffing our company, business planning, raising capital, acquiring or discovering product candidates and securing related intellectual property rights, conducting discovery, research and development activities for our programs and planning for potential commercialization. To date, we have not generated any product revenue and have financed our operations primarily through the private placement of our securities and through public offerings of our common stock. Through December 31, 2021, we had received gross cash proceeds of $87.5 million from sales of our preferred stock; gross cash proceeds, before deducting underwriting discounts and commissions and expenses, of $428.1 million from sales of our common stock through our initial public offering and follow-on offerings; and gross cash proceeds, before deducting commissions and expenses, of $23.5 million from sales of our common stock through our “at-the-market” (ATM) facility.

Additionally, we have incurred significant operating losses. Our ability to generate product revenue sufficient to achieve profitability will depend heavily on the successful development and eventual commercialization of one or more of our current or future product candidates and programs. Our net losses were $119.1 million and $119.7 million for the years

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ended December 31, 2021 and 2020, respectively. As of December 31, 2021, we had an accumulated deficit of $383.5 million. We expect to continue to incur significant expenses for at least the next several years as we advance our current and future product candidates from discovery through preclinical development and clinical trials and seek regulatory approval of our product candidates. Our pipeline consists of five investigational gene therapies, two of which are currently in clinical development. As a result, further development of these programs will require us to expend significant resources to advance these candidates. In addition, if we obtain marketing approval for any of our product candidates, we expect to incur significant commercialization expenses related to product manufacturing, marketing, sales and distribution. We may also incur expenses in connection with the in-licensing or acquisition of additional product candidates.

We will need substantial 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 with proceeds from outside sources, with a majority of such proceeds to be derived from sales of equity, including the net proceeds from our follow-on offerings and sales of common stock under our “at-the-market” facility, or ATM Facility, as well as proceeds from our Loan and Security Agreement, or Term Loan Agreement, with the lenders party thereto from time to time, or the Lenders, and Silicon Valley Bank, as administrative agent and collateral agent for the Lenders, or the Agent. We may also pursue additional funding from outside sources, including our expansion of, or our entry into, new borrowing arrangements; research and development incentive payments from the Australian government; and our entry into potential future collaboration agreements for one or more of our programs. 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 or delay our pursuit of potential in-licenses or acquisitions.

Because of the numerous risks and uncertainties associated with product development, we are unable to 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, we may be unable to continue our operations at planned levels and be forced to reduce or terminate our operations.

As of December 31, 2021, we had cash and cash equivalents of $189.6 million. We believe that our existing cash and cash equivalents as of December 31, 2021 will enable us to fund our operating expenses and capital expenditure requirements into the first quarter of 2024. We have based this estimate on assumptions that may prove to be wrong, and we could exhaust our available capital resources sooner than we expect. See “Liquidity and Capital Resources.” To finance our operations beyond that point, we will need to raise additional capital, which cannot be assured.

Components of Our Consolidated Results of Operations

Operating Expenses

Research and Development Expenses

Research and development expenses consist primarily of costs incurred in connection with the discovery and development of our product candidates. We expense research and development costs as incurred. These expenses consist of costs incurred in connection with the development of our product candidates, including:

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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.

Our direct research and development expenses are tracked on a program-by-program basis for our product candidates and consist primarily of external costs, such as fees paid to outside consultants, CROs, CMOs, and central laboratories in connection with our preclinical development, process development, manufacturing and clinical development activities. Our direct research and development expenses by program also include fees incurred under license agreements. We do not allocate employee costs or facility expenses, including depreciation or other indirect costs, to specific programs because these costs are deployed across multiple programs and, as such, are not separately classified. We use internal resources primarily to oversee the research and discovery as well as for managing our preclinical development, process development, manufacturing and clinical development activities. These employees work across multiple programs and, therefore, we do not track their costs by program.

The table below summarizes our research and development expenses related to our product candidates (in thousands):

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. As a result, we expect that our research and development expenses will increase substantially over the next several years, particularly as we increase personnel costs, including stock-based compensation, contractor costs and facilities costs, as we continue to advance the development of our product candidates. We also expect to incur additional expenses related to milestone and royalty payments payable to third parties with whom we have entered into license agreements to acquire the rights to our product candidates.

The successful development and commercialization of our product candidates is highly uncertain. At this time, we cannot reasonably estimate or know the nature, timing and costs of the efforts that will be necessary to complete the preclinical and clinical development of any of our product candidates or when, if ever, material net cash inflows may commence from any of our product candidates. This uncertainty is due to the numerous risks and uncertainties associated with product development and commercialization, including the uncertainty of:

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We may never succeed in achieving regulatory approval for any of our product candidates. We may obtain unexpected results from our clinical trials. We may elect to discontinue, delay or modify clinical trials of some product candidates or focus on others. Any changes in the outcome of any of these variables with respect to the development of our product candidates in preclinical and clinical development could mean a significant change in the costs and timing associated with the development of these product candidates. For example, if the FDA, or another regulatory authority were to delay our planned start of clinical trials or require us to conduct clinical trials or other testing beyond those that we currently expect, or if we experience significant delays in enrollment in any of our planned clinical trials, we could be required to expend significant additional financial resources and time on the completion of clinical development of that product candidate. Identifying potential product candidates and conducting preclinical testing 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 and achieve product sales. In addition, our product candidates, if approved, may not achieve commercial success.

General and Administrative Expenses

General and administrative expenses consist primarily of salaries, related benefits, travel and stock-based compensation expense for personnel in executive, finance and administrative functions. General and administrative expenses also include professional fees for legal, consulting, accounting and audit services.

We anticipate that our general and administrative expenses will increase in the future as we increase our headcount to support our continued research activities and development of our product candidates. We also anticipate that we will continue to incur increased accounting, audit, legal, compliance, director and officer insurance costs as well as investor and public relations expenses associated with being a public company. We anticipate the additional costs for these services will substantially increase our general and administrative expenses. Additionally, if and when we believe a regulatory approval of a product candidate appears likely, we anticipate an increase in payroll and other commercialization-related expenses as a result of our preparation for commercial operations, especially as it relates to the sales and marketing of our product candidate.

Other (Expense) Income, net

Other (expense) income, net primarily consists of interest income earned on our cash and cash equivalents, changes in foreign currency, and interest expense related to our Term Loan Agreement.

Consolidated Results of Operations

Comparison of the Years Ended December 31, 2021 and 2020

The following table summarizes our consolidated results of operations (in thousands):

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Research and Development Expenses

Research and development expenses decreased by $4.1 million to $83.1 million for the year ended December 31, 2021, from approximately $87.2 million for the year ended December 31, 2020. This decrease was attributable to $9.1 million in non-recurring license fees incurred in 2020, which included an $8.0 million expense related to a one-time, upfront fee paid as consideration for in-licensing the Hunter syndrome program, a $1.2 million decrease in non-cash stock-based compensation, and a $0.5 million decrease in other expenses. These decreases were partially offset by a $6.7 million increase in personnel-related costs.

General and Administrative Expenses

General and administrative expenses increased by $2.7 million to $35.7 million for the year ended December 31, 2021, from $33.0 million for the year ended December 31, 2020. This increase was attributable to a $4.2 million increase in non-cash stock-based compensation and a $1.5 million increase in personnel-related costs, offset in part by a decrease in other expenses, primarily related to facilities costs, professional fees and legal fees, of $3.0 million.

Other (Expense) Income, net

Other (expense) income, net was $(0.3) million for the year ended December 31, 2021, compared to $0.5 million of other income, net for the year ended December 31, 2020. The change was primarily due to a decrease of $0.6 million related to a decrease in interest income and $0.2 million in interest expense related to the Term Loan Agreement which was entered into during 2021.

Liquidity and Capital Resources

Since our inception, we have not generated any revenue and have incurred significant operating losses and negative cash flows from our operations. We have funded our operations to date primarily with proceeds from the sale of preferred stock and our common stock through our initial public offering, or IPO, and we have raised additional capital through subsequent follow-on offerings and our ATM Facility, as well as through our Term Loan Agreement. Through December 31, 2021, we had received gross cash proceeds of $87.5 million from sales of our preferred stock; gross cash proceeds, before deducting underwriting discounts and commissions and expenses, of $428.1 million from sales of our common stock through our IPO and follow-on public offerings; $23.5 million in gross proceeds from the sale of our common stock under our ATM Facility; and we had drawn $15.0 million in term loans under our Term Loan Agreement.

On July 1, 2019, we filed a shelf registration statement on Form S-3 with the SEC, or the July 2019 Shelf, which covers the offering, issuance and sale by us of up to an aggregate of $200.0 million of our common stock, preferred stock, debt securities, warrants and/or units. We simultaneously entered into a Sales Agreement with Cowen and Company, LLC, as sales agent, to provide for the offering, issuance and sale by us of up to $50.0 million of our common stock from time to time in ATM offerings under the July 2019 Shelf. The July 2019 Shelf was declared effective by the SEC on July 10, 2019.

On December 20, 2019, we filed a shelf registration statement on Form S-3 with the SEC, or the December 2019 Shelf, which covers the offering, issuance and sale by us of up to an aggregate of $250.0 million of our common stock, preferred stock, debt securities, warrants and/or units. The December 2019 Shelf was declared effective by the SEC on January 14, 2020.

In July 2019, we closed an underwritten public offering, or the July 2019 Follow-On Offering, under the July 2019 Shelf of 7,475,000 shares of our common stock at a public offering price of $18.50 per share, which included 975,000 shares of our common stock resulting from the full exercise of the underwriters’ option to purchase additional shares at the public offering price, less underwriting discounts and commissions. The net proceeds to us from this offering, after deducting underwriting discounts and commissions and other offering expenses payable by us, were $129.5 million.

In February 2020, we closed an underwritten public offering, or the February 2020 Follow-On Offering, under the December 2019 Shelf of 4,350,000 shares of our common stock at a public offering price of $23.00 per share, less underwriting discounts and commissions. The net proceeds to us from this offering, after deducting underwriting discounts and commissions and other offering expenses payable by us, were $93.6 million.

In June 2020, we sold an aggregate of 384,140 shares of common stock under the ATM Facility for net proceeds, after deducting commissions and other offering expenses payable by us, of $8.1 million.

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In November 2020, we closed an underwritten public offering, or the November 2020 Follow-On Offering, of 5,000,000 shares of our common stock at a public offering price of $15.00 per share, less underwriting discounts and commissions. The net proceeds to us from the November 2020 Follow-On Offering, after deducting underwriting discounts and commissions and other offering expenses payable by us, were $70.2 million.

In May 2021, we sold an aggregate of 1,829,268 shares of common stock under the ATM Facility for net proceeds, after deducting commissions and other offering expenses payable by us, of $14.5 million. As of December 31, 2021, approximately $26.5 million of common stock remained available for future issuance under the ATM Facility.

On November 2, 2021, or the Closing Date, we entered into the Term Loan Agreement. The Term Loan Agreement provided for (i) on the Closing Date, $30.0 million aggregate principal amount of term loans available through October 31, 2023; (ii) an additional $20.0 million in term loan facilities available through October 31, 2023 upon the achievement of certain regulatory or clinical milestones prior to the time of draw, or the Milestone Funding; and (iii) an additional discretionary $15.0 million term loan facility available upon our request and approval by the Agent and the Lenders, or, collectively, the Term Loans. We drew $15.0 million in term loans on the Closing Date. As a result of the deprioritization of our Fabry disease program, we are no longer able to draw the $20.0 million of Milestone Funding per the terms of the Term Loan Agreement. The loan repayment schedule provides for interest only payments until November 1, 2024, followed by consecutive monthly payments of principal and interest. All unpaid principal and accrued and unpaid interest with respect to each term loan is due and payable in full on October 1, 2026.

As of December 31, 2021, we had cash and cash equivalents of $189.6 million. Cash in excess of immediate requirements is invested primarily with a view to liquidity and capital preservation. We believe that our existing cash and cash equivalents as of December 31, 2021 will enable us to fund our operating expenses and capital expenditure requirements into the first quarter of 2024.

Cash Flows

The following table summarizes our cash flows for each of the periods presented (in thousands):

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Operating Activities

During the year ended December 31, 2021, operating activities used $98.0 million of cash and cash equivalents, resulting from our net loss of $119.1 million, partially off-set by net cash provided by changes in our operating assets and liabilities of $1.3 million and non-cash charges of $19.8 million. Net cash provided by changes in our operating assets and liabilities for the year ended December 31, 2021 consists primarily of a $2.1 million increase in accrued expenses and other current liabilities, a $0.4 million decrease in other assets, and a $0.8 million increase in accounts payable, partially offset by a $2.0 million increase in prepaid expenses and other current assets. The increase in accrued expenses and other current liabilities was primarily due to an increase in accrued compensation and benefit costs.

During the year ended December 31, 2020, operating activities used $98.8 million of cash and cash equivalents, resulting from our net loss of $119.7 million, partially off-set by net cash provided by changes in our operating assets and liabilities of $4.2 million and non-cash charges of $16.7 million. Net cash provided by changes in our operating assets and liabilities for the year ended December 31, 2020 consists primarily of a $3.9 million increase in accrued expenses and other current liabilities, a $1.1 million decrease in prepaid expenses and other current assets and a $0.1 million decrease in other assets, partially offset by a $0.9 million decrease in accounts payable. The increase in accrued expenses and other current liabilities was primarily due to a $3.4 million increase in accrued compensation and benefit costs.

Investing Activities

Net cash used in investing activities was $2.5 million for the year ended December 31, 2021 compared to $1.2 million for the year ended December 31, 2020. The increase in cash used in investing activities was primarily due to an increase in purchases of property and equipment.

Financing Activities

Net cash provided by financing activities was $30.4 million for the year ended December 31, 2021 compared to $172.6 million for the year ended December 31, 2020. The decrease in cash provided by financing activities was primarily due to the $14.6 million in proceeds raised through our ATM Facility in 2021 and $15.0 million raised through the Term Loan Agreement in 2021, as compared to proceeds of $164.1 million raised collectively from the February 2020 Follow-On Offering and November 2020 Follow-On Offering, and proceeds of $8.1 million raised from our ATM Facility in 2020.

Funding Requirements

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. Our expenses will also increase as we:

We believe that our $189.6 million of existing cash and cash equivalents as of December 31, 2021, will enable us to fund our operating expenses and capital expenditure requirements into the first quarter of 2024. We have based these

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estimates on assumptions that may prove to be wrong, and we could utilize our available capital resources sooner than we expect. If we receive regulatory approval for any of our product candidates, we expect to incur significant commercialization expenses related to product manufacturing, sales, marketing and distribution, depending on where we choose to commercialize.

Until such time, if ever, that we can generate product revenue sufficient to achieve profitability, we expect to finance our cash needs through a combination of equity offerings, debt financings, collaboration agreements, government and other third-party funding, strategic alliances, licensing arrangements or marketing and distribution arrangements. Debt financing and preferred equity financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends. If we raise additional funds through government and other third-party funding, collaboration agreements, strategic alliances, licensing arrangements or marketing and distribution arrangements, we may have to relinquish valuable rights to our technologies, 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 when needed, we may be required to delay, limit, reduce or terminate our product development or future commercialization efforts or grant rights to develop and market products or product candidates that we would otherwise prefer to develop and market ourselves.

Contractual Obligations and Commitments

The following table summarizes our contractual obligations as of December 31, 2021 and the effects that such obligations are expected to have on our liquidity and cash flows in future periods (in thousands):

We enter into contracts in the normal course of business with CROs, CMOs and other third parties for clinical trials, preclinical research studies and testing and manufacturing services. Payments due upon cancellation consist only of payments for services provided or expenses incurred, including noncancelable obligations of our service providers, up to the date of cancellation. These payments are not included in the preceding table as the amount and timing of such payments are not known.

In addition, pursuant to our license agreements with UHN, BioMarin, The University of Manchester, Papillon Therapeutics and the Lund University rights holders, we are required to make certain milestone and royalty payments to our licensors. See “Business—License Agreements” for additional details regarding our payment obligations to these licensors.

Critical Accounting Policies and Significant Judgments and Estimates

Our consolidated financial statements are 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 judgments that affect the reported amounts of assets, liabilities, revenue, costs and expenses, and the disclosure of contingent assets and liabilities in our 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 more detail in Note 2 “Summary of Significant Accounting Policies” to our consolidated financial statements appearing elsewhere in this Annual Report, 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.

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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. We periodically confirm the accuracy of these estimates with the service providers and make adjustments if necessary. Examples of estimated accrued research and development expenses include fees paid to:

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 research institutions and CROs that 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 measure stock options and other stock-based awards granted to employees and members of our board of directors for their services as directors based on the fair value on the date of the grant and recognize the corresponding compensation expense of those awards over the requisite service period, which is generally the vesting period of the respective award. We have issued stock options, restricted stock and restricted stock units with service-based vesting conditions.

Modifications to stock-based awards are treated as an exchange of the original award for a new award with total compensation equal to the grant-date fair value of the original award plus any incremental value of the modification. The incremental value is based on the excess of the fair value of the modified award over the fair value of the original award immediately before the modification.

Prior to the adoption of Accounting Standards Update (ASU) No. 2018-07, Compensation—Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting (ASU 2018-07), as discussed in Note 2 “Summary of Significant Accounting Policies” to our consolidated financial statements appearing elsewhere in this Annual Report, the measurement date for non-employee awards was generally the date the services were completed, resulting in financial reporting period adjustments to stock-based compensation during the vesting terms for changes in the fair value of the awards. After the adoption of ASU 2018-07, the measurement date for non-employee awards is the later of the adoption date of ASU 2018-07, or the date of grant, without change in the fair value of the award.

We estimate the fair value of each stock option grant using the Black-Scholes option-pricing model, which uses as inputs the estimated fair value of our common stock and assumptions we make for the volatility of our common stock, the expected term of our stock options, the risk-free interest rate for a period that approximates the expected term of our stock options and our expected dividend yield.

We determined the assumptions for the Black-Scholes option-pricing model as discussed below. Each of these inputs is subjective and generally requires significant judgment to determine.

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If any of the assumptions used in the Black-Scholes model change significantly, stock-based compensation for future awards may differ materially compared with the awards granted previously.

Emerging Growth Company Status

We are an “emerging growth company,” as defined in the JOBS Act, and we may take advantage of certain exemptions from various reporting requirements that are applicable to other public companies that are not emerging growth companies. We may take advantage of these exemptions until we are no longer an emerging growth company. Section 107 of the JOBS Act provides that an emerging growth company can take advantage of the extended transition period afforded by the JOBS Act for the implementation of new or revised accounting standards. We have elected to use the extended transition period for complying with new or revised accounting standards and, as a result of this election, our financial statements may not be comparable to companies that comply with public company effective dates. We may take advantage of these exemptions up until the last day of the fiscal year following the fifth anniversary of our IPO or such earlier time that we are no longer an emerging growth company. We would cease to be an emerging growth company if we have more than $1.07 billion in annual revenue, we have more than $700.0 million in market value of our stock held by non-affiliates or we issue more than $1.0 billion of non-convertible debt securities over a three-year period.

Off-Balance Sheet Arrangements

We did not have, during the periods presented, and we do not currently have, any off-balance sheet arrangements, as defined in the rules and regulations of the Securities and Exchange Commission.

Recently Issued Accounting Pronouncements

A description of recently issued accounting pronouncements that may potentially impact our financial position and results of operations is disclosed in Note 2 “Summary of Significant Accounting Policies” to our audited financial statements appearing elsewhere in this Annual Report.

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