aTyr Pharma (NASDAQ: ATYR) shares fell after company outlined revised Phase 3 trial strategy

aTyr Pharma shares declined sharply after the company announced plans for a new Phase 3 study of efzofitimod in pulmonary sarcoidosis following discussions with the U.S. Food and Drug Administration.

The biotech company said it planned to submit an investigational new drug application in June 2026 for the revised trial, which incorporated feedback received from the FDA after review of the previous EFZO-FIT Phase 3 study.

The planned global trial was expected to enroll around 372 patients with chronic symptomatic pulmonary sarcoidosis and restrictive lung disease. The study would evaluate changes in forced vital capacity (FVC) as the primary endpoint, alongside the King’s Sarcoidosis Questionnaire-Lung score as a key secondary measure.

Patients in the study were expected to receive intravenous doses of efzofitimod every three weeks over a 54-week treatment period, representing a more frequent dosing schedule than previous trials.

aTyr said earlier EFZO-FIT data suggested patients with restrictive lung disease experienced clinically meaningful improvements in lung function when treated with efzofitimod compared with placebo.

The stock decline reflected investor concerns over the need for an additional late-stage trial, which could extend development timelines and increase costs before any potential approval. However, the revised study design and continued FDA engagement suggested the company remained committed to advancing efzofitimod in a disease area where treatment options remain limited.