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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We may encounter substantial delays and other challenges in our ongoing or planned clinical trials or we may fail to demonstrate safety and efficacy 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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There is no established FDA regulatory pathway for approval of a drug in pulmonary sarcoidosis. 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), even if successful, may not be sufficient to support FDA approval, which would materially and adversely harm our business;

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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;

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