Dostarlimab Plus Chemotherapy Reduces the Risk of Progression or Death for Patients With dMMR/MSI-H Advanced or Recurrent Endometrial Cancer

According to additional results from the RUBY trial, dostarlimab plus chemotherapy reduces the risk of progression or death among patients with mismatch repair deficient (dMMR) or microsatellite instability-high (MSI-H) primary advanced or recurrent endometrial cancer. 

As previously reported in part 1, results from the RUBY trial “demonstrated improved survival in patients with primary advanced or recurrent endometrial cancer treated with dostarlimab plus carboplatin-paclitaxel versus placebo plus carboplatin-paclitaxel,” stated Matthew Powell, MD, Washington University School of Medicine, St. Louis, Missouri, and coauthors. “Here, we examine additional efficacy and safety data from patients with mismatch repair deficient/microsatellite instability-high” disease. 

There were a total of 118 patients with dMMR/MSI-H disease enrolled in the RUBY trial. Patients were randomized to receive either 500 mg of dostarlimab (dMMR/MSI-H population, n = 53) or placebo (dMMR/MSI-H population, n = 65) plus carboplatin and paclitaxel every 3 weeks for 6 cycles followed by dostarlimab or placebo every 6 weeks for up to 3 years. In the dMMR/MSI-H population, investigator-assessed progression-free survival (PFS) compared to blinded independent central review, sensitivity analyses of patients in the source-verified population compared to the randomized population, and safety were completed. 

At first-interim analysis, dostarlimab plus carboplatin and paclitaxel reduced the risk of progression or death by 72% (P < .0001). Sensitivity analyses of source-verified dMMR/MSI-H population and randomized dMMR/MSI-H population were consistent for PFS and overall survival. Safety results were consistent with prior findings in the overall population. 

“All primary and secondary efficacy assessments demonstrate the consistent benefit of dostarlimab plus carboplatin-paclitaxel,” concluded Dr Powell et al. “The improvements seen in survival and the manageable safety profile support the favorable benefit–risk profile for dostarlimab plus carboplatin-paclitaxel in patients with dMMR/MSI-H primary advanced or recurrent [endometrial cancer].”

Source: 

Powell MA, Cibula D, O’Malley et al. Efficacy and safety of dostarlimab in combination with chemotherapy in patients with dMMR/MSI-H primary advanced or recurrent endometrial cancer in a phase 3, randomized, placebo-controlled trial (ENGOT-EN6-NSGO/GOG-3031/RUBY). Gynecol Oncol. Published online: November 11, 2024. doi: 10.1016/j.ygyno.2024.10.022