The aTyr class action alleges that aTyr and its top executives made false and misleading statements about the efficacy of its drug, Efzofitimod, leading investors to purchase stock at artificially inflated prices.
At the heart of the allegations is aTyr’s Phase 3, randomized, double-blind, placebo-controlled study, known as EFZO-FIT, which evaluated intravenous Efzofitimod in patients with pulmonary sarcoidosis. The drug was intended to help patients reduce their dependency on steroids.
According to the complaint, throughout the Class Period, aTyr executives expressed overwhelmingly positive statements and confidence in the study’s design, particularly its forced taper approach intended to gauge the drug’s ability to allow patients to completely wean themselves off steroids.
However, the lawsuit claims that concurrently with these optimistic pronouncements, the company was allegedly concealing material adverse facts concerning Efzofitimod’s capability to allow a patient to completely taper their steroid usage—a key measure of efficacy. The lawsuit asserts that aTyr’s statements crossed the line into securities law violations by allegedly misrepresenting the drug’s true prospects.
The truth, as alleged in the complaint, came to light on Monday, September 15, 2025. Pre-market, aTyr hosted an investor call announcing that the EFZO-FIT study did not meet its primary endpoint: the change from baseline in mean daily oral corticosteroid (OSC) dose at week 48.
The disappointing topline results prompted a swift and brutal market reaction. aTyr’s common stock, which had closed at $6.03 per share on the preceding Friday, September 12, cratered to close at just $1.02 per share on September 15—a catastrophic one-day decline of 83.2%.
In its post-announcement comments, the company stated that it would engage with the Food and Drug Administration (FDA) to determine a path forward, acknowledging the setback.
CASE TIMELINE
