aTYR Pharma, Inc.

We are a clinical stage biotechnology company that uses evolutionary intelligence to develop new therapies for fibrosis and inflammation based on tRNA synthetase biology. tRNA synthetases are ancient, essential proteins with evolved domains that regulate various extracellular pathways in humans. Our discovery platform aims to identify therapeutic intervention points by uncovering signaling pathways driven by our proprietary library of domains derived from all 20 tRNA synthetases. Our primary therapeutic candidate is efzofitimod, a novel biologic immunomodulator in clinical development for interstitial lung disease (ILD). ILD comprises immune-mediated disorders causing lung inflammation and fibrosis. Efzofitimod is a tRNA synthetase-derived therapy that specifically modulates activated myeloid cells via neuropilin-2 (NRP2) to resolve inflammation without suppressing the immune system, potentially preventing fibrosis progression. ILDs are predominantly immune-mediated and characterized by chronic inflammation, which can lead to progressive lung fibrosis. Treatment options for ILD are limited, indicating a high unmet medical need. Major forms of ILD include sarcoidosis and systemic sclerosis (SSc, also known as scleroderma)-associated ILD (SSc-ILD). The U.S. Food and Drug Administration (FDA) has granted efzofitimod orphan drug designations for sarcoidosis and SSc, and Fast Track designations for pulmonary sarcoidosis and SSc-ILD. The European Commission has granted efzofitimod orphan drug designations for sarcoidosis and SSc, based on the European Medicines Agency (EMA) Committee for Orphan Medicinal Products (COMP) opinion. The Pharmaceutical and Medical Devices Agency (PMDA) has granted efzofitimod orphan drug designation for sarcoidosis to Kyorin Pharmaceutical Co., Ltd. (Kyorin), our partner in Japan. In September 2025, we announced top-line data from a global Phase 3 randomized, double-blind, placebo-controlled clinical trial (the EFZO-FIT study) evaluating efzofitimod's efficacy and safety in patients with pulmonary sarcoidosis.