Drugmaker Rapt Therapeutics has been ordered by the FDA to immediately pause a pair of Phase 2 clinical trials due to a case of liver failure in one study participant.
The studies—a Phase 2b trial of zelnecirnon in atopic dermatitis and a separate Phase 2a trial of the drug in cases of asthma— were part of a trio of studies looking at zelnecirnon that had enrolled a total of approximately 350 patients. No evidence of liver toxicity had been observed in any other current trial participant or in previous nonclinical studies, according to Rapt.
“This is an unfortunate and unexpected event, and we are working diligently to get more information on this case,” Brian Wong, MD, PhD, president and CEO of Rapt Therapeutics, said in a statement. “Patient safety is our top priority and we will work with the FDA to resolve this as quickly as possible.”
Wong provided additional context in a conference call this week, saying the patient whose liver failed had a “particularly complex” medical history, including drug allergies, an autoimmune disease and an active case of Covid-19. He said the company is still investigating to fill in “considerable gaps” in information as to what exactly transpired.
“We expect a formal letter from the FDA with more details, including information needed to lift the hold,” Wong said. “This formal feedback will be critical to direct our investigation and identify the best path forward.”
The value of company shares took a beating in the wake of the news, falling more than 60% in premarket trading, according to MarketWatch. The report noted zelnecirnon is one of two primary initiatives for Rapt, the other being an experimental cancer treatment, tivumecirnon.
While dosing and enrollment of patients in the zelnecirnon trials has been halted, the tivumecirnon trial is unaffected by the FDA’s action.
Evan joined TriMed in 2011, writing primarily for Health Imaging. Prior to diving into medical journalism, Evan worked for the Nine Network of Public Media in St. Louis. He also has worked in public relations and education. Evan studied journalism at the University of Missouri, with an emphasis on broadcast media.