Daiichi Sankyo and Merck voluntarily withdrew their BLA for ifinatamab deruxtecan (i-dxd) in extensive-stage small-cell lung cancer after progressing on or after platinum chemotherapy. The companies framed the action as a regulatory filing decision tied to the evidentiary bar for the accelerated approval strategy. The withdrawal adds to pressure on the B7-H3 ADC strategy in SCLC and further complicates the competitive timetable for companies seeking fast-path approvals in an aggressively evolving lung cancer treatment space. For the partners, the next steps center on redefining the development plan and re-aligning clinical evidence generation to regulatory expectations.