Safety Issue Prompts Zelnecirnon Termination

Rapt Therapeutics says it is terminating its zelnecirnon (RPT193) drug development program due to a serious safety issue. Zelnecirnon was being evaluated in two randomized, placebo-controlled Phase 2 clinical trials in asthma and atopic dermatitis (AD), and both trials were placed on clinical hold by FDA earlier this year due to a serious liver injury requiring transplant in one patient in the AD trial.

“No liver toxicity nor other treatment-related SAEs were reported in any other trial participant,” the company says. It subsequently discontinued both studies before completing their full enrollment based on feedback from FDA.

“In light of the agency’s feedback, we do not see a viable path forward for zelnecirnon, although we continue to believe that CCR4 remains an exciting target with the potential to provide a safe, oral therapeutic option across a number of inflammatory diseases,” Rapt says.