Daiichi Sankyo and Merck withdrew their BLA for ifinatamab deruxtecan in extensive-stage small-cell lung cancer after FDA feedback, according to the report. The companies said they voluntarily pulled the application, ending an accelerated-approval effort for adult patients whose disease progressed on or after platinum chemotherapy. The withdrawal adds another high-profile hurdle to the Merck–Daiichi lung cancer ADC collaboration, coming amid escalating scrutiny of accelerated pathways and the completeness of efficacy and safety datasets. For the sector, the move underscores the execution risk inherent in ADC development—especially when accelerated regulatory strategies depend on specific subgroup performance and sufficiency of supporting evidence.