Rosen Law Firm said it is investigating potential securities claims involving Disc Medicine, Inc. after the U.S. Food and Drug Administration (FDA, the U.S. drug regulator) issued a Complete Response Letter (formal notice declining approval) for the company's bitopertin program on February 13, 2026. The letter said Disc Medicine's new drug application (NDA, formal request to market a drug) could not be approved because of uncertainties that would require additional evidence. Disc Medicine's stock fell 22% that day. Rosen said it is preparing a class action and that investors who purchased Disc Medicine securities may be eligible to seek compensation under a contingency fee arrangement.