Kezar's Zetomipzomib for Autoimmune Hepatitis Faces Second FDA Clinical Hold Amid Safety Concerns

The FDA has imposed a partial clinical hold on Kezar Life Sciences' phase 2a PORTOLA trial of zetomipzomib for autoimmune hepatitis, marking the second such regulatory action in just a few months[1][2]. This hold comes in the wake of serious concerns raised during a separate trial for lupus nephritis that resulted in fatalities and trial termination. The current PORTOLA trial, however, has not reported serious adverse events. The FDA's decision specifically restricts the transition of placebo patients to zetomipzomib in the trial's open-label phase, as a precaution despite the ongoing trial proceeding without recent adverse incidents of interest[1][2].