The lawsuit, filed in the United States District Court for the Southern District of New York, alleges that Regeneron mischaracterized a slowdown in progression-free survival event accrual as a sign of treatment efficacy. According to the complaint, the company failed to disclose that this delay was actually a warning sign that the study's statistical assumptions were flawed and that the trial faced a heightened risk of missing its primary endpoint. Shareholders contend that these omissions led them to overpay for the company's securities.

Following the disclosure of a protocol expansion and the subsequent announcement that the trial failed to reach statistical significance, Regeneron shares dropped approximately 13.95%, representing a decline of $102.09 per share from the Class Period high. Joseph E. Levi of Levi & Korsinsky LLP, the firm representing the plaintiffs, stated that the case hinges on the company's obligation to provide a fair assessment of clinical-trial risks. Investors who suffered losses during the specified period are eligible to contact the firm to review their potential participation in the action.