aTyr Pharma's Phase 3 EFZO-FIT Study of Efzofitimod in Pulmonary Sarcoidosis Fails to Meet Primary Goal

aTyr Pharma's Phase 3 EFZO-FIT study of efzofitimod in pulmonary sarcoidosis failed to meet its primary goal, with the change from baseline in mean daily oral corticosteroid dose at week 48 averaging 2.79 mg for efzofitimod compared to 3.52 mg for placebo. The company plans to work with the FDA to decide next steps for efzofitimod in pulmonary sarcoidosis.

San Diego, CA, September 12, 2025 - aTyr Pharma, Inc. (Nasdaq: ATYR) today announced topline results from its Phase 3 EFZO-FIT™ study of efzofitimod in pulmonary sarcoidosis. The study, which enrolled 268 patients, failed to meet its primary endpoint of change in mean daily oral corticosteroid (OCS) dose at week 48. The drug showed a reduction of 2.79 mg for efzofitimod compared to 3.52 mg for placebo (p=0.3313), which was not statistically significant.

Despite missing the primary endpoint, the study yielded notable secondary outcomes. Notably, 52.6% of patients treated with 5.0 mg/kg efzofitimod achieved complete steroid withdrawal compared to 40.2% on placebo (p=0.0919). Additionally, there was a clinical improvement in the King’s Sarcoidosis Questionnaire (KSQ)-Lung score at week 48 for 5.0 mg/kg efzofitimod compared to placebo (p=0.0479), with a greater proportion of patients achieving both steroid withdrawal and KSQ-Lung score improvement with efzofitimod (29.5% vs 14.4%, p=0.0199).

The drug was well-tolerated, with no significant safety concerns reported. aTyr Pharma plans to engage with the U.S. Food and Drug Administration (FDA) to determine the path forward for efzofitimod in pulmonary sarcoidosis treatment. The company will host a conference call and webcast today at 8:30 am ET / 5:30 am PT to discuss the results in detail.

The study’s statistical analysis plan was designed on a hierarchical assessment basis, meaning that since the primary endpoint was not met, all subsequent statistical testing is reported as nominal findings. The higher than anticipated placebo response, with 40.2% of placebo patients achieving complete steroid withdrawal, suggests either a strong placebo effect or potential issues with the trial design and endpoints selected.

The market will likely view these results negatively, despite management's attempt to highlight positive secondary findings. The company's plan to engage with the FDA suggests significant uncertainty about the program's future, which typically translates to increased investment risk. The ongoing EFZO-CONNECT™ study in systemic sclerosis-related ILD now takes on heightened importance as a potential alternative pathway for the company.

The results of EFZO-FIT™ demonstrate not only strong evidence of clinical efficacy for efzofitimod’s effect on quality of life and its capacity to facilitate steroid withdrawal, but also increased confidence that steroids overall can be reduced to manage symptoms and lung function without the fear of worsening disease.

References
aTyr Pharma Announces Topline Results from Phase 3 EFZO-FIT™ Study of Efzofitimod in Pulmonary Sarcoidosis^[1] https://www.stocktitan.net/news/ATYR/a-tyr-pharma-announces-topline-results-from-phase-3-efzo-fittm-study-24jgpzxchpve.html