Rocket Pharmaceuticals Faces FDA Clinical Hold After Patient Death

Rocket Pharmaceuticals is facing significant challenges following a patient death and clinical hold in its Danon disease gene therapy trial due to capillary leak syndrome (CLS), a serious adverse event possibly linked to a new C3 inhibitor added to the immunosuppression protocol. Analysts from William Blair, BMO Capital Markets, and others maintain an overall optimistic outlook, affirming outperform ratings and emphasizing the therapy's potential benefits despite the stock's decline of over 50%. The clinical hold is seen as a necessary safety measure, with expectations for further FDA discussions to clarify the CLS mechanism and a path forward. The adverse event appears isolated to the RP-A501 program and does not affect Rocket's other cardiovascular gene therapy candidate, RP-A601, which uses a different vector and immunosuppression approach. Despite the setbacks and market pressure, Rocket Pharmaceuticals maintains strong liquidity, with analysts highlighting a viable path forward contingent upon implementing revised safety protocols. The broader gene therapy field may face increased scrutiny as a result, but the severity of Danon disease underpins continued confidence in the program's therapeutic promise.