aTYR PHARMA INC

Risk Factors Summary

Below is a summary of the principal factors that make an investment in our securities speculative or risky. This summary does not address all of the risks that we face. Additional discussion of the risks summarized in this risk factors summary, and other risks that we face, can be found in Part I, Item 1A “Risk Factors” and should be carefully considered, together with other information in this Annual Report and our other filings with the SEC before making investment decisions regarding our securities.

Investing in our securities involves substantial risk. The risks described under Part I, Item 1A “Risk Factors” of this Annual Report may cause us to not realize the full benefits of our strengths or may cause us to be unable to successfully execute all or part of our strategy. Some of the more significant risks we face include the following:

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There is no established U.S. Food and Drug Administration (FDA) regulatory pathway for approval of a drug in pulmonary sarcoidosis. In addition, a Phase 3 clinical trial that does not meet its primary endpoint may not support an FDA regulatory pathway for approval. As a result, our Phase 3 randomized, double-blind, placebo-controlled clinical trial to evaluate the efficacy and safety of efzofitimod in patients with pulmonary sarcoidosis (the EFZO-FIT study) may not be sufficient to support FDA approval and may require additional clinical trials, which would materially and adversely harm our business;

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We may encounter substantial delays and other challenges in our ongoing or planned clinical trials or we may fail to demonstrate safety and efficacy, such as the failure to meet the primary endpoint in the EFZO-FIT study, to the satisfaction of applicable regulatory authorities;

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If we are unable to successfully complete or otherwise advance clinical development, obtain regulatory or marketing approval for, or successfully commercialize our therapeutic product candidates, including efzofitimod, or experience significant delays in doing so, our business will be materially harmed;

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We may face contracted development and manufacturing organization (CDMO) manufacturing stoppages and other CDMO challenges associated with the clinical or commercial manufacture of our product candidates or regulatory activities required for a biologics license application (BLA) submission;

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Our current product candidates and any other product candidates that we may develop from our discovery platform represent novel therapeutic approaches, which may cause significant delays or may not result in any commercially viable drugs;

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Our therapeutic product candidates may cause undesirable side effects or have other properties that could delay or prevent their regulatory approval, limit the commercial profile of an approved label, or result in significant negative consequences following marketing approval, if any;

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We will need to raise additional capital or enter into strategic partnering relationships to fund our operations;

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We are a pre-commercial biotechnology company and have incurred significant losses since our inception and anticipate that we will continue to incur significant losses for the foreseeable future;

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We depend on our existing collaborations and may depend on collaborations with additional third parties for the development and commercialization of certain of our product candidates. If our collaborations are not successful, we may not be able to capitalize on the market potential of these product candidates;

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If we are unable to obtain, maintain or protect intellectual property rights related to our product candidates, or if the scope of such intellectual property protection is not sufficiently broad, we may not be able to compete effectively in our markets;

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Our future success depends on our ability to retain key employees, consultants and advisors and to attract, retain and motivate qualified personnel;

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Unfavorable macroeconomic conditions could adversely affect our business, financial condition or results of operations; and

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The market price of our common stock historically has been highly volatile and is likely to continue to be volatile, and you could lose all or part of your investment.

PART I