ATyr Pharma Stock Sinks, Plans FDA Review After Mixed Phase 3 Results

Author: Vandana Singh | September 15, 2025 11:24am

Biotech firm aTyr Pharma Inc. (NASDAQ:ATYR) plummeted over 81% at last check on Monday, with a session volume of 34.7 million compared to the average volume of 4.83 million as per data from Benzinga Pro.

In other words, many investors are selling. Why? The company’s Phase 3 trial results of its drug efzofitimod for pulmonary sarcoidosis, and the trial failed its primary endpoint.

The trial involved 268 patients with pulmonary sarcoidosis, a major form of interstitial lung disease. ATyr will reportedly engage the Federal Drug Administration (FDA) to determine potential regulatory pathways, despite the primary endpoint miss.

The study’s statistical analysis plan was designed on a hierarchical assessment basis, as such since the primary endpoint was not met, all subsequent statistical testing is reported as nominal findings.

• Steroid Reduction: The change from baseline in mean daily OCS dose reduced to an average of 2.79 mg for 5.0 mg/kg efzofitimod vs 3.52 mg for placebo (p=0.3313).  
• Complete steroid withdrawal was achieved for 52.6% of patients treated with 5.0 mg/kg efzofitimod vs 40.2% on placebo (p=0.0919).
• Change from baseline in KSQ-Lung score of 10.36 for 5.0 mg/kg efzofitimod vs 6.19 for placebo (p=0.0479)
• Proportion of patients who achieved complete steroid withdrawal with stable KSQ-Lung score was 46.9% of patients on 5.0 mg/kg of efzofitimod vs 35.7% on placebo (p=0.1241).
• Proportion of patients who achieved complete steroid withdrawal with KSQ-Lung improvement was 29.5% of patients on 5.0 mg/kg efzofitimod vs 14.4% in placebo (p=0.0199).
• Lung function, as measured by forced vital capacity (FVC) at week 48, was maintained. Change from baseline in absolute percent predicted FVC of -1.81 for patients in the 5.0 mg/kg efzofitimod vs -2.11 in placebo (p=0.7875).

Generally well-tolerated at both the 3.0 mg/kg and 5.0 mg/kg doses, consistent with a previously observed safety profile in all trials conducted to date.

Based on these findings, which the company says indicate drug activity for efzofitimod as evidenced by improvements across multiple clinically relevant efficacy endpoints, the company plans to engage with the U.S. Food and Drug Administration to review the results and determine the path forward for efzofitimod in pulmonary sarcoidosis.

Price Action: ATYR stock is down 82.42% at $1.06 at the last check on Monday.

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