aTyr Pharma Announces FDA Alignment on Phase 3 Study for Efzofitimod

What Happened
On September 24, 2026 aTyr Pharma, Inc. announced it has reached alignment with the U.S. Food and Drug Administration on the protocol for a planned global Phase 3 study of efzofitimod in patients with chronic, symptomatic pulmonary sarcoidosis with restrictive lung disease. The company expects to begin study-related activities in Q4 2026 and will focus on regulatory submissions in the U.S. and Europe as the program advances. The Planned Phase 3 Study is randomized, double-blind and placebo-controlled, running 54 weeks with two parallel cohorts dosed IV every 3 weeks.

Key Details

• Planned study size: up to ~372 patients with symptomatic pulmonary sarcoidosis and restrictive lung disease (FVC % predicted ≤ 80%, normal FEV1/FVC).
• Dosing/length: 5.0 mg/kg efzofitimod vs placebo, IV every 3 weeks for 17 doses over 54 weeks.
• Endpoints: primary = change from baseline in forced vital capacity (FVC) at Week 48; key secondary = change in King’s Sarcoidosis Questionnaire (KSQ)-Lung score at Week 48.
• Rationale: design supported by a subgroup analysis from the Company’s Phase 3 EFZO-FIT™ study showing clinically meaningful FVC benefit and KSQ-Lung improvements for the 5.0 mg/kg group; findings presented at WASOG 2026.
• Funding note: company states additional capital (equity/debt, grants, partnerships or licensing) will be required to develop efzofitimod in this Planned Phase 3 Study.

Why It Matters
Reaching FDA alignment on a Phase 3 protocol is a material development milestone that clarifies the planned path forward for efzofitimod in pulmonary sarcoidosis (study size, dosing, endpoints and timeline). For investors, this increases visibility into near-term development plans (study activities starting Q4 2026) but also highlights the need for additional financing, which could affect the company’s capital structure. The filing also underscores that earlier Phase 3 subgroup data supported the chosen patient population and endpoints, though the company cautions results and future milestones remain subject to risks and uncertainties.