aTyr Pharma Inc saw its shares decline roughly 15% in premarket trading Tuesday after the company announced plans to launch a new Phase 3 clinical trial testing efzofitimod in pulmonary sarcoidosis.
The San Diego-based biotech said it plans to submit an investigational new drug application in June 2026. The filing will reflect input the company received from the U.S. Food and Drug Administration during a Type C meeting that reviewed outcomes from the prior EFZO-FIT Phase 3 study.
The planned trial will enroll patients with chronic, symptomatic pulmonary sarcoidosis characterized by restrictive lung disease. It is designed as a global, randomized, double-blind, placebo-controlled study and is expected to recruit approximately 372 patients across a 54-week period.
Investigators will administer either 5.0 mg/kg efzofitimod or placebo intravenously once every three weeks for a total of 17 doses. That dosing frequency represents an increase in administration cadence compared with previous trials, which dosed once every four weeks.
The study’s primary efficacy measure will be change from baseline in forced vital capacity, or FVC, at week 48. The key secondary endpoint will be the change in the King’s Sarcoidosis Questionnaire-Lung score, or KSQ-Lung. According to the FDA feedback noted by the company, both FVC and KSQ-Lung are direct measures of how patients function and feel.
Enrollment criteria will focus on patients with moderate to severe pulmonary sarcoidosis with restrictive lung disease who are receiving a stable regimen of up to 5.0 mg daily oral corticosteroid and/or a background immunosuppressant. The document outlining the program indicates that the primary endpoint timing is set at week 48, while the KSQ-Lung change is designated as the key secondary outcome.
aTyr cited evidence from the earlier EFZO-FIT study showing that patients with restrictive lung disease experienced a clinically meaningful benefit in FVC when treated with efzofitimod versus placebo.
Context and implications
The company’s announcement links the new protocol directly to FDA feedback from the Type C meeting and positions the trial to test both lung function and patient-reported breathing-related quality of life. The shift to more frequent intravenous dosing and the specified enrollment and baseline medication criteria are notable design elements highlighted by the company.
What comes next
aTyr intends to file the investigational new drug application in June 2026 and to proceed with the global randomized study thereafter. The company has pointed to subgroup data from EFZO-FIT as the basis for focusing on patients with restrictive lung disease in this next trial.
Key points
- aTyr’s stock fell about 15% in premarket trading after announcing plans for a new Phase 3 efzofitimod trial.
- The planned global, randomized, double-blind, placebo-controlled study will enroll roughly 372 patients over 54 weeks and use FVC as the primary endpoint with KSQ-Lung as the key secondary endpoint.
- The trial will test 5.0 mg/kg efzofitimod dosed intravenously once every three weeks for 17 doses in patients on stable low-dose corticosteroid and/or background immunosuppressant therapy.
Risks and uncertainties
- The trial outcome is uncertain - the company noted benefit in a subgroup from EFZO-FIT but the new study’s success is not guaranteed in a broader population.
- The investigational new drug submission timing and subsequent trial initiation depend on the company’s June 2026 filing and regulatory interactions with the FDA.
- Market reaction to the announcement has already affected the company’s share price, reflecting investor sensitivity to clinical development updates in the biotech sector.