FDA to Review Dostarlimab Plus Chemo for Expanded Endometrial Cancer Indication

The Food and Drug Administration (FDA) has accepted for Priority Review the supplemental Biologics License Application (sBLA) for dostarlimab-gxly in combination with standard of care chemotherapy for all adult patients with primary advanced or recurrent endometrial cancer, including those with mismatch repair proficient (MMRp)/microsatellite stable (MSS) tumors.

The sBLA is supported by data from part 1 of the randomized, double-blind, multicenter phase 3 RUBY trial (ClinicalTrials.gov Identifier: NCT03981796), which evaluated the efficacy and safety of dostarlimab-gxly plus chemotherapy (carboplatin and paclitaxel) followed by dostarlimab-gxly vs placebo plus carboplatin-paclitaxel followed by placebo. The primary outcome measures were progression free survival and overall survival (OS).

Findings showed in the overall study population, treatment with dostarlimab-gxly plus chemotherapy reduced the risk of death by 31% vs placebo plus chemotherapy (hazard ratio [HR], 0.69 [95% CI, 0.539-0.890]; P =.002). Median OS was 44.6 months (95% CI, 32.6, not reached) in the dostarlimab-gxly plus chemotherapy arm and 28.2 months (95% CI, 22.1-35.6) in the placebo plus chemotherapy arm.

In a prespecified exploratory analysis of the MMRp/MSS population, treatment with dostarlimab-gxly plus chemotherapy reduced the risk of death by 21% vs placebo plus chemotherapy (HR, 0.79 [95% CI, 0.602-1.044]). Median OS was 34 months (95% CI, 28.6-not reached) in the dostarlimab-gxly plus chemotherapy group and 27 months (95% CI, 21.5-35.6) in the placebo plus chemotherapy group.

A regulatory decision on the sBLA is expected on August 23, 2024.

Dostarlimab-gxly is currently marketed under the brand name Jemperli for use in combination with carboplatin and paclitaxel in the treatment of adults with primary advanced or recurrent endometrial cancer that is either mismatch repair deficient (dMMR) or microsatellite instability-high (MSI-H).