The FDA granted priority review to Daiichi Sankyo and Merck’s B7-H3-directed antibody-drug conjugate ifinatamab deruxtecan. The BLA acceptance and priority review apply to patients with advanced extensive-stage small-cell lung cancer, advancing the program within a faster review timeline than standard processing. The decision is likely to accelerate the expected timing of regulatory resolution for a high-unmet-need patient population. It also adds to the momentum for B7-H3 ADC strategies as sponsors work to establish differentiation through safety and efficacy profiles in later-line settings. For developers and partners, the priority review status signals the agency’s intent to treat the application as time-sensitive, contingent on the completeness and robustness of the submission package.