aTyr Pharma (NASDAQ:ATYR) saw its stock tumble 80% following the announcement that its Phase 3 EFZO-FIT trial of efzofitimod in pulmonary sarcoidosis did not meet the primary endpoint.
The study’s main objective—change from baseline in mean daily oral corticosteroid dose at week 48—was not achieved. Patients receiving 5.0 mg/kg efzofitimod reduced their dose to an average of 2.79 mg compared with 3.52 mg for the placebo group (p=0.3313), a difference that was not statistically significant.
Despite missing the primary endpoint, aTyr highlighted several positive outcomes. The 5.0 mg/kg efzofitimod cohort demonstrated improvement in the King’s Sarcoidosis Questionnaire-Lung (KSQ-Lung) score at week 48 relative to placebo (p=0.0479). Furthermore, 52.6% of patients on 5.0 mg/kg efzofitimod achieved complete steroid withdrawal at week 48 versus 40.2% for placebo (p=0.0919).
A higher proportion of patients in the 5.0 mg/kg group achieved both full steroid withdrawal and KSQ-Lung score improvement (29.5%) compared to the placebo group (14.4%) (p=0.0199).
The treatment was well-tolerated at both the 3.0 mg/kg and 5.0 mg/kg doses, maintaining a safety profile consistent with prior studies.
Daniel Culver, Chair of the Department of Pulmonary Medicine at the Cleveland Clinic and principal investigator, described the trial as “an important step forward for the field” and noted it is the largest interventional study conducted in sarcoidosis to date.
aTyr plans to consult with the FDA to determine the next steps for efzofitimod in pulmonary sarcoidosis, pointing to evidence of activity across multiple clinically meaningful efficacy endpoints despite the missed primary goal.
The company will present topline EFZO-FIT results at the European Respiratory Society Congress on September 30, 2025.
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