SOUTH SAN FRANCISCO, Calif. - RAPT Therapeutics, Inc. (NASDAQ:RAPT), a biopharmaceutical company engaged in the development of oral small molecule therapies, today announced a clinical hold on two of its drug trials following a serious adverse event. The U.S. Food and Drug Administration (FDA) has verbally informed the company of a hold on its Phase 2b trial for atopic dermatitis and Phase 2a trial for asthma concerning its drug candidate zelnecirnon (RPT193).
The clinical hold was prompted by a case of liver failure in a patient participating in the atopic dermatitis study, which may be related to the administration of zelnecirnon. As a result, the company has ceased dosing in both trials and stopped enrolling new participants. This hold does not affect another ongoing trial for a different drug candidate, tivumecirnon (FLX475), targeting oncology.
Approximately 350 patients have been enrolled in the zelnecirnon studies, including the two Phase 2 trials and an earlier Phase 1a/1b study. There has been no previous indication of liver toxicity in these or in nonclinical studies. The patient who experienced liver failure had a complex medical history, including a known drug allergy, autoimmune disease, and use of an herbal supplement linked to liver failure, as well as a concurrent COVID-19 infection.
RAPT Therapeutics is conducting a thorough investigation into the incident and is working closely with the FDA to resolve the issue as swiftly as possible. "Patient safety is our top priority," stated Brian Wong, M.D., Ph.D., President and CEO of RAPT Therapeutics. The company will be hosting a webcast conference call today to discuss the clinical hold and provide further details.
This development represents a significant setback for RAPT Therapeutics, which specializes in treatments for inflammatory diseases and cancer. The company's proprietary discovery and development engine has produced two drug candidates, both targeting the C-C motif chemokine receptor 4 (CCR4). While the future of zelnecirnon is now uncertain, the company continues to advance a range of targets in the discovery stage.
The information in this article is based on a press release statement from RAPT Therapeutics.
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