Rapt Therapeutics (RAPT.O) has announced the U.S. FDA had placed on hold two mid-stage trials of the company’s drug to treat eczema and asthma, after liver failure was observed in one of the patients.
Shares of the San Francisco-based company hit a record low of $8.5 in early trade.
Rapt said it was analyzing the patient’s history, and called the liver toxicity an “isolated event”.
According to CEO, Brian Wong, the patient had a drug allergy to Dupixent, Regeneron (REGN.O) and Sanofi’s drug for the conditions, and had also undergone thyroid hormone replacement therapy for an autoimmune condition called Hashimoto’s disease.
The patient was reported to have a COVID-19 infection as well during the time of the event, and was using ashwagandha, a herbal supplement known to be associated with liver failure, according to the company.
Stifel analyst Alex Thompson said the clinical hold “represents a major setback” for Rapt and could result in “a meaningful delay in trial timelines”.
Rapt had enrolled about 350 patients across the two mid-stage trials and a previous early-stage study of the drug, zelnecirnon, but no evidence of liver toxicity was observed with any other patient.
