The FDA granted priority review to Daiichi Sankyo and Merck’s B7-H3-directed antibody-drug conjugate ifinatamab deruxtecan. The acceptance covers an accelerated timeline under the BLA filing for advanced extensive-stage small-cell lung cancer. A priority review can signal readiness for faster label decisions once review concludes, which can influence trial timing and payer and treatment-planning expectations for oncology clinicians. The decision keeps ADC development momentum on the B7-H3 target, a space that has seen intense competition as companies chase differentiation via linker payload selection and clinical activity profiles.