Merck and Kelun-Biotech’s TROP2-directed ADC sacituzumab tirumotecan (sac-TMT) delivered a major Phase 3 progression-free survival result in first-line, PD-L1-positive non-small cell lung cancer, cutting the risk of disease progression or death by 65% versus Keytruda alone, according to an ASCO 2026 abstract. In the OptiTROP-Lung05 study in China, median PFS was not reached in the combo arm after a median follow-up of 10.5 months, compared with 5.7 months for Keytruda monotherapy. Response rates were reported at just over 70% for the combination versus 42% with Keytruda alone, with discontinuation rates lower than or comparable to the control arm. While OS data were not mature at the data cutoff, the magnitude of the PFS readout—paired with the randomized Phase 3 design—raises the stakes for how ADC–PD-1 combinations could reshape treatment sequencing in frontline lung cancer.