May 22, 2023

Location: Ballroom C (Level 3), Walter E. Washington Convention Center The poster presents findings that investigate the modulatory functions of efzofitimod on monocytes by evaluating peripheral blood mononuclear cells from pulmonary sarcoidosis patients or healthy donors for surface marker expression by flow cytometry and cytokine/chemokine secretion by immunoassay. Neuropilin-2, the binding partner for efzofitimod, is expressed on circulating monocytes and macrophages in lung granulomas from pulmonary sarcoidosis patients and exhibits a more inflammatory phenotype compared to healthy donors. Efzofitimod modulates immune responses in myeloid cells by downregulating pro-inflammatory cytokines and receptors that are dysregulated in sarcoidosis, including TNFa, IL-6, MIP-1a and MCP-1. These findings enhance our understanding of efzofitimod’s mechanism of action and demonstrate the way in which it modulates inflammatory responses in pulmonary sarcoidosis patients. Location: Area F, Hall C (Lower Level), Walter E. Washington Convention Center The poster presents findings from a population pharmacokinetic model and exposure-efficacy analyses using data from a Phase 1 study of efzofitimod in healthy volunteers and Phase 1b/2a study in patients with pulmonary sarcoidosis. Analyses assessed the relationship between efzofitimod exposure and three prespecified efficacy parameters and showed that administration of efzofitimod led to an exposure-dependent decrease in the extent of oral corticosteroid usage, increase in lung function as measured by percent predicted forced vital capacity and improvement in clinical symptoms as measured by the King’s Sarcoidosis Questionnaire-Lung score. These findings of a positive exposure-efficacy analysis across multiple clinically relevant endpoints support proof-of-concept and efficacy in pulmonary sarcoidosis. The company is also hosting an Industry Theater presentation. Details appear below. Title: Efzofitimod: An Emerging Treatment for Sarcoidosis? Session Format: Industry Theater Presentation Speaker: Daniel A. Culver, D.O, Chair of Pulmonary Medicine, Cleveland Clinic Date and Time: Tuesday, May 23, 2023, at 1:30 p.m. Location: Exhibit Hall A-B, Booth #102, Walter E. Washington Convention Center Dr. Culver will discuss efzofitimod as an emerging treatment for sarcoidosis, including its novel mechanism as a way to resolve inflammation and prevent the progression of fibrosis in patients with pulmonary sarcoidosis and the Phase 3 EFZO-FIT™ study, which is currently enrolling patients with pulmonary sarcoidosis. About Efzofitimod aTyr is developing efzofitimod as a potential therapeutic for patients with fibrotic lung disease. Efzofitimod, a fusion protein comprised of the immunomodulatory domain of histidyl-tRNA synthetase fused to the FC region of a human antibody, is a selective modulator of neuropilin-2 that downregulates innate and adaptive immune response in inflammatory disease states. aTyr’s lead indication for efzofitimod is pulmonary sarcoidosis, a major form of interstitial lung disease. Clinical proof-of-concept for efzofitimod was recently established in a Phase 1b/2a multiple-ascending dose, placebo-controlled study of efzofitimod in patients with pulmonary sarcoidosis, which demonstrated safety and a consistent dose response and trends of benefit of efzofitimod compared to placebo on key efficacy endpoints, including steroid reduction, lung function, clinical symptoms and inflammatory biomarkers. aTyr is currently conducting EFZO-FIT™, a global pivotal Phase 3 study of efzofitimod in pulmonary sarcoidosis. About aTyr aTyr is a biotherapeutics company engaged in the discovery and development of first-in-class medicines from its proprietary tRNA synthetase platform. aTyr’s research and development efforts are concentrated on a newly discovered area of biology, the extracellular functionality and signaling pathways of tRNA synthetases. aTyr has built a global intellectual property estate directed to a potential pipeline of protein compositions derived from 20 tRNA synthetase genes and their extracellular targets. aTyr’s primary focus is efzofitimod, a clinical-stage product candidate which binds to the neuropilin-2 receptor and is designed to downregulate immune engagement in fibrotic lung disease. For more information, please visit http://www.atyrpharma.com . Forward-Looking Statements This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements are usually identified by the use of words such as “believes,” “expects,” “intends,” “may,” “plans,” “forward,” “potential,” “will,” and variations of such words or similar expressions. We intend these forward-looking statements to be covered by such safe harbor provisions for forward-looking statements and are making this statement for purposes of complying with those safe harbor provisions. These forward-looking statements include, among others, statements regarding the potential of efzofitimod to be a transformative, disease modifying therapy for ILD, and the potential applications of efzofitimod. These forward-looking statements also reflect our current views about our plans, intentions, expectations, strategies and prospects, which are based on the information currently available to us and on assumptions we have made. 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