aTyr Pharma is a clinical-stage biotech developing biologics for fibrosis and inflammatory diseases, with a platform built around the extracellular functions of tRNA synthetase proteins. The company has no approved products and no commercial revenue. Its lead asset is efzofitimod, an IV biologic immunomodulator targeting interstitial lung disease (ILD) — a group of immune-mediated conditions causing chronic lung inflammation and fibrotic scarring. Efzofitimod works by binding to the NRP2 receptor on activated myeloid cells, selectively dampening inflammation without broadly suppressing the immune system. The primary target indication is pulmonary sarcoidosis, a rare inflammatory lung disease affecting roughly 200,000 Americans, where no purpose-built approved therapy exists. aTyr is also developing efzofitimod for SSc-ILD (lung disease associated with scleroderma). The Phase 3 EFZO-FIT study in pulmonary sarcoidosis reported top-line data in September 2025 and did not meet its primary endpoint of steroid reduction, creating meaningful uncertainty about the regulatory path forward. aTyr has scheduled an FDA meeting in April 2026 to discuss options. A Phase 2 study in SSc-ILD is ongoing. If approved, aTyr plans to commercialize efzofitimod in the U.S. directly, targeting pulmonologists and rheumatologists, while partnering with Kyorin Pharmaceutical for Japan. Manufacturing is outsourced to CDMOs. Beyond efzofitimod, aTyr has two preclinical candidates — ATYR0101 targeting fibrosis and ATYR0750 targeting liver disorders — with no announced clinical timelines.