Prior FDA approval of the combination was granted for adults with primary advanced or recurrent endometrial cancer that was mismatch repair deficient (dMMR) or microsatellite instability–high (MSI-H).
The expanded approval, granted following a priority review, was based on efficacy and safety demonstrated in the randomized, controlled, multicenter RUBY trial, which included 494 patients who were randomized to receive the dostarlimab-gxly regimen or placebo plus carboplatin and paclitaxel, followed by placebo.
Researchers observed a significant improvement in median overall survival with treatment vs placebo in the overall population — 44.6 vs 28.2 months, respectively (hazard ratio [HR], 0.69). Median progression-free survival was also significantly better in the treatment vs placebo group — 11.8 vs 7.9 months, respectively (HR, 0.64).
“Today’s expanded approval will offer even more patients the opportunity for improved outcomes,” Matthew Powell, MD, of Washington University School of Medicine, and principal investigator on the RUBY trial, said in a press release. “This is the only immuno-oncology treatment regimen that has shown a statistically significant overall survival benefit for the full patient population, which is a meaningful step forward in treating this challenging cancer.”
Adverse reactions occurring in at least 20% of patients receiving dostarlimab-gxly include anemia, increased creatinine levels, peripheral neuropathy, decreased white blood cell counts, fatigue, nausea, alopecia, low platelet counts, increased glucose levels, lymphopenia, neutropenia, liver function test abnormalities, arthralgia, rash, constipation, diarrhea, decreased albumin levels, abdominal pain, dyspnea, decreased appetite, increased amylase levels, urinary tract infection, and vomiting. Immune-mediated adverse reactions with dostarlimab-gxly were similar to those previously reported.
The recommended dostarlimab-gxly dose, according to the full prescribing information, is 500 mg every 3 weeks for six cycles administered before carboplatin and paclitaxel if given on the same day, followed by 1000 mg monotherapy every 6 weeks until disease progression or unacceptable toxicity, or up to 3 years.
A version of this article first appeared on Medscape.com.