RAPT Therapeutics, Inc. (NASDAQ: RAPT) is currently experiencing a notable surge in its performance on the US stock market. At the latest check during the current session, RAPT stock has demonstrated a commendable increase of 19.51%, reaching $8.21. This positive trend persists despite a regulatory setback encountered in one of its clinical trials.
According to a press release from RAPT Therapeutics (RAPT), the FDA has verbally notified that the company’s Phase 2b trial of zelnecirnon (RPT193) in atopic dermatitis and its Phase 2a trial in asthma have been placed on clinical hold.
Awaiting official word from the FDA on the clinical hold, RAPT notes that the reason for this decision is a major adverse event of liver failure that was seen in an atopic dermatitis study participant. The exact cause of this adverse event remains undetermined, although it is potentially linked to zelnecirnon.
Consequently, administration of zelnecirnon has been ceased in both clinical trials, alongside a suspension of new participant enrollments. It is important to note that the clinical hold does not extend to RAPT’s ongoing trial of tivumecirnon (FLX475) in oncology.
Across the three zelnecirnon trials – comprising the two Phase 2 trials and an earlier Phase 1a/1b study – approximately 350 patients have been enrolled. To date, there have been no indications of liver toxicity observed in any other trial participants, nor in nonclinical studies.
RAPT is conducting a thorough investigation into the aforementioned case, which involves a patient with a complex medical history, including prior drug allergies, autoimmune conditions necessitating thyroid hormone replacement therapy, and the use of an herbal supplement associated with liver failure.
Additionally, the patient reported a prior COVID-19 infection at the time of the event. Characterizing the FDA’s decision as regrettable and unforeseen, RAPT is actively striving to obtain further insights into the matter.
Emphasizing patient safety as paramount, the company remains dedicated to collaborating with the FDA to expediently resolve the issue at hand.
