Adding pembrolizumab to standard chemotherapy increased progression-free survival In patients with advanced or recurrent endometrial cancer, compared with chemotherapy alone, researchers report. “The efficacy curves in the two [mismatch repair–deficient (dMMR)] cohorts separated early in the course of treatment, with a preserved separation throughout the evaluation period,” the authors write. “This benefit was observed in most subgroups, including among patients who had received previous adjuvant chemotherapy or radiation and among those with less common histologic subtypes.”
The double-blind, placebo-controlled, randomized, phase 3 trial included 816 patients with stage III or IVA or stage IVB or recurrent endometrial cancer. They received pembrolizumab or placebo with combination therapy with paclitaxel plus carboplatin in 6 cycles every 3 weeks, followed by up to 14 maintenance cycles every 6 weeks. Stratified based on whether they had dMMR or mismatch repair–proficient (pMMR) disease, the participants had these outcomes based on a primary outcome of progression-free survival: “In the 12-month analysis, Kaplan–Meier estimates of progression-free survival in the dMMR cohort were 74% in the pembrolizumab group and 38% in the placebo group (hazard ratio for progression or death, 0.30; 95% confidence interval [CI], 0.19 to 0.48; P <0.001), a 70% difference in relative risk. In the pMMR cohort, median progression-free survival was 13.1 months with pembrolizumab and 8.7 months with placebo (hazard ratio, 0.54; 95% CI, 0.41 to 0.71; P <0.001). Adverse events were as expected for pembrolizumab and combination chemotherapy.”