Ahead of ASCO 2026, Merck’s licensed TROP2 ADC sacituzumab tirumotecan (sac-TMT) drew investor attention after OptiTROP-Lung05 interim Phase 3 data showed a major PFS cut versus Keytruda alone in first-line PD-L1-positive NSCLC. The interim analysis reported a 65% progression risk reduction and a response rate above 70% for the combination, with overall survival not yet mature at the September cutoff. Analysts framed the results as a meaningful positioning point for Merck’s global lung cancer program and for ADC-Class competition in frontline settings.