Fulcrum Therapeutics is scrapping development of its lead sickle cell disease candidate, pociredir, and will pursue a strategic review after the FDA raised heightened concerns about risks and benefits. The agency’s position follows emerging safety signals associated with another PRC2 inhibitor class member, Ipsen’s Tazverik (tazemetostat), which was withdrawn from the U.S. market over secondary blood cancer concerns. Fulcrum said it had presented mechanistic and clinical rationale to the FDA based on target differences within PRC2 subunits and said no new severe safety signals were observed to date in pociredir, but the FDA ultimately determined malignancy risk is comparable across PRC2 complex interventions. The company disclosed it had received the official meeting record and that it sees no viable regulatory path forward. Shares moved sharply on the news, reflecting the severity of the FDA’s intervention and the difficulty of restarting programs in the PRC2 space without a clear pathway to mitigate the perceived malignancy hazard.