aTyr Pharma stock falls after Phase 3 study misses primary endpoint

Published 15/09/2025, 13:08
© Reuters.

Investing.com -- aTyr Pharma (NASDAQ:ATYR) stock fell 80% after the company announced that its Phase 3 EFZO-FIT study of efzofitimod in pulmonary sarcoidosis failed to meet its primary endpoint.

The study did not achieve its primary goal of change from baseline in mean daily oral corticosteroid dose at week 48. Patients treated with 5.0 mg/kg efzofitimod showed a reduction to an average of 2.79 mg compared to 3.52 mg for placebo (p=0.3313), which was not statistically significant.

Despite missing the main endpoint, the company highlighted several positive findings. The 5.0 mg/kg efzofitimod group showed improvement in the King’s Sarcoidosis Questionnaire-Lung score at week 48 compared to placebo (p=0.0479). Additionally, 52.6% of patients treated with 5.0 mg/kg efzofitimod achieved complete steroid withdrawal at week 48 versus 40.2% on placebo (p=0.0919).

A greater proportion of patients achieved both complete steroid withdrawal and KSQ-Lung score improvement in the 5.0 mg/kg efzofitimod group (29.5%) compared to placebo (14.4%) (p=0.0199).

The drug was well-tolerated at both the 3.0 mg/kg and 5.0 mg/kg doses, with a safety profile consistent with previous trials.

Daniel Culver, Chair of the Department of Pulmonary Medicine at the Cleveland Clinic and principal investigator, called the trial "an important step forward for the field" as the largest interventional study completed in sarcoidosis to date.

aTyr plans to engage with the FDA to determine the path forward for efzofitimod in pulmonary sarcoidosis, citing evidence of drug activity across multiple clinically relevant efficacy endpoints despite the missed primary endpoint.

The company will present the EFZO-FIT topline results at the upcoming European Respiratory Society Congress on September 30, 2025.

This article was generated with the support of AI and reviewed by an editor. For more information see our T&C.

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