Merck & Co. announced FDA Breakthrough Therapy designation for sacituzumab tirumotecan (sac-TMT) to treat advanced or metastatic nonsquamous non-small cell lung cancer with EGFR mutations. Sac-TMT is a TROP2-directed ADC developed with Kelun-Biotech, targeting patients whose disease progressed after TKI and platinum-based chemotherapy. Merck is advancing sac-TMT's clinical development globally, including 10 ongoing Phase 3 studies, and recently received its first marketing authorization in China for certain unresectable locally advanced or metastatic triple-negative breast cancer.