Overview

A class action lawsuit has been filed against aTyr Pharma Inc. (“aTyr” or the “Company”) and certain of the Company’s former senior executive officers alleging violations of the federal securities laws. The Company’s common stock traded on the NASDAQ Stock Market (the “NASDAQ”) under the symbol “ATYR.”

The aTyr class action lawsuit was brought on behalf of all persons and entities who purchased or otherwise acquired aTyr common stock between January 16, 2025, and September 12, 2025, both dates inclusive, (the “Class Period”).

aTyr is a clinical stage biotechnology company leveraging evolutionary intelligence to translate tRNA synthetase biology into new therapies for fibrosis and inflammation. The Company’s discovery platform is focused on unlocking hidden therapeutic intervention points by uncovering signaling pathways driven by its proprietary library of domains derived from all 20 tRNA synthetases.

The lawsuit alleges that aTyr Pharma and its executives misled investors about the company’s Phase 3 clinical trial, known as EFZO-FIT, which was designed to evaluate the safety and efficacy of intravenous Efzofitimod in patients with pulmonary sarcoidosis. Throughout the class period, defendants made numerous positive statements about the trial, expressing confidence in the study’s “forced taper” design—a method intended to demonstrate the drug’s ability to reduce or eliminate the need for steroid use among patients.

According to the lawsuit, these statements were materially false and misleading because defendants failed to disclose critical adverse information about Efzofitimod’s actual efficacy, particularly its limited ability to enable patients to completely taper off steroids. By concealing these material facts and promoting overly optimistic claims about the study’s design and potential outcomes, the company allegedly caused aTyr’s stock to trade at artificially inflated prices.

The truth was revealed on September 15, 2025, when aTyr announced before the market opened that the EFZO-FIT study did not meet its primary endpoint—specifically, the change from baseline in mean daily oral corticosteroid (OSC) dose at week 48. During an investor call that day, the company confirmed the disappointing topline results and stated that it would engage with the FDA to determine the next steps for Efzofitimod’s development.

Following this disclosure, aTyr’s stock price collapsed, falling from $6.03 per share on September 12, 2025, to $1.02 per share on September 15, 2025, representing a single-day decline of 83.2%. The lawsuit alleges that, as a result of defendants’ false and misleading statements and omissions, investors suffered substantial financial losses when the true results of the EFZO-FIT trial became public.

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If you purchased or otherwise acquired aTyr common stock between January 16, 2025, and September 12, 2025, both dates inclusive, and you wish to serve as lead plaintiff in this lawsuit, we encourage you to submit your information to DiCello Levitt LLP via the form on this page. 

You can also contact DiCello Levitt partner Brian O’Mara by calling (888) 287-9005 or at investors@dicellolevitt.com. 

The deadline to apply to the Court to serve as lead plaintiff in the aTyr class action lawsuit is December 8, 2025.