Multinational phase 3 trial of dostarlimab plus chemotherapy for primary advanced or recurrent endometrial cancer

With the standard first-line treatment of carboplatin-paclitaxel (CP), patients with primary advanced or recurrent endometrial cancer (A/R EC) have a median overall survival of less than 3 years. Use of anti-PD-1s with chemotherapy has improved outcomes in multiple tumor types. The multinational phase 3 RUBY trial evaluated dostarlimab-CP versus placebo-PC for A/R EC. PFS was significantly longer with dostarlimab-CP compared with placebo-CP among patients with dMMR/MSI-H disease, and among all patients. OS was significantly better with dostarlimab-CP compared with placebo-CP among all patients. Discontinuation of dostarlimab/placebo due to a TEAE occurred in 17.4% of patients receiving dostarlimab-CP and 9.3% of patients receiving placebo-CP. The authors conclude that addition of dostarlimab to CP resulted in improved outcomes in A/R EC patients.