ASCO Conference Coverage

Dostarlimab Plus Chemotherapy Delays Quality of Life Deterioration in Advanced Endometrial Cancer

Kate Young

Key Highlights

  • Dostarlimab plus carboplatin-paclitaxel (DOST+CP) delayed quality of life (QoL) deterioration across multiple domains in patients with mismatch repair deficient/microsatellite instability-high (dMMR/MSI-H) endometrial cancer.
  • In the overall study population, time to QoL improvement was generally similar between DOST+CP and placebo+CP (PBO+CP) arms.
  • Significant earlier improvement in pain (overall population) and role function (dMMR/MSI-H group) was observed with DOST+CP.
  • These QoL results reinforce previously reported survival benefits and support the safety and efficacy of dostarlimab.

In a post hoc analysis of the phase 3 RUBY trial (NCT03981796), the combination of dostarlimab with carboplatin-paclitaxel (DOST+CP) demonstrated a comparable time to quality of life (QoL) improvement and a delayed time to deterioration in several domains when compared to placebo plus chemotherapy (PBO+CP) in patients with primary advanced or recurrent endometrial cancer.

Endometrial cancer, especially in advanced or recurrent stages, poses significant challenges to both survival and quality of life. The RUBY trial previously established that DOST+CP improves progression-free and overall survival. Given the importance of patient-reported outcomes, this analysis aimed to elucidate how treatment affects patients’ lived experiences, specifically the timing of QoL changes.

In this randomized, double-arm study, 494 patients were assigned 1:1 to receive either DOST+CP or PBO+CP every 3 weeks for six cycles, followed by monotherapy (dostarlimab or placebo) every 6 weeks for up to 3 years. QoL was assessed at each visit using the EORTC QLQ-C30 and EN24 questionnaires. Improvement or deterioration was defined as a ≥10-point change from baseline. Median follow-up was 37.2 months as of the cutoff date of September 22, 2023.

Results showed no major differences between treatment arms in time to first QoL improvement (TTI1) across most domains. However, pain improved significantly earlier in the overall population receiving DOST+CP (HR, 1.37, P = .008), and role function improved earlier in the dMMR/MSI-H subgroup (HR, 1.67, P=0.048). Regarding time to first deterioration (TTD1), DOST+CP delayed deterioration in multiple domains for the dMMR/MSI-H population, including global QoL (HR, 0.61, P = .027), role function (HR, 0.58, P = .015), and sexual interest (HR, 0.38, P = .001), among others. In contrast, TTD1 in the overall population did not significantly differ between groups.

“These results on patient experience of treatment further support the efficacy and safety data of dostarlimab for use in patients with pA/rEC,” the study authors concluded.

Resources:
Heitz F, Willmott L, Mathiesen HF, et al. Time to quality of life (QoL) improvement or deterioration in patients with primary advanced or recurrent endometrial cancer treated with dostarlimab plus chemotherapy in the ENGOT-EN6-NSGO/GOG-3031/RUBY trial. Presented at: 2025 American Society of Clinical Oncology Annual Meeting; 2025 May 30–June 3; Chicago, IL.