Updated phase 3 RUBY trial findings strengthened the case for dostarlimab plus carboplatin and paclitaxel in dMMR/MSI-H primary advanced or recurrent endometrial cancer. At a median follow-up of 55.6 months, the abstract showed durable progression-free survival separation between the combination and chemotherapy alone. The study reported 4-year PFS rates of 57.9% with dostarlimab versus 15.7% with chemotherapy, with mixture cure modeling estimating that 54% of patients may have curative potential. Median overall survival also favored the immunotherapy regimen (44.6 vs 28.2 months; HR 0.69), with only a small number of new PFS events since the earlier analysis. For the oncology pipeline, the durability signals may reshape treatment discussions in a biomarker-defined subgroup where outcomes are typically variable and follow-up is critical for confirming long-term disease control.