On April 22, the U.S. Food and Drug Administration (FDA) granted accelerated approval to dostarlimab-gxly (Jemperli) for adult patients with mismatch repair–deficient (dMMR) recurrent or advanced endometrial cancer, as determined by an FDA-approved test, that has progressed on or following a prior platinum-containing regimen.
GARNET Trial
Efficacy was evaluated based on cohort A1 in the GARNET trial (ClinicalTrials.gov identifier NCT02715284), a multicenter, multicohort, open-label trial in patients with advanced solid tumors. The efficacy population consisted of 71 patients with dMMR recurrent or advanced endometrial cancer whose disease progressed on or after a platinum-containing regimen. Patients received dostarlimab-gxly at 500 mg intravenously every 3 weeks for four doses followed by 1,000 mg intravenously every 6 weeks. The main efficacy endpoints were overall response rate and duration of response, as assessed by blinded independent central review according to Response Evaluation Criteria in Solid Tumors version 1.1.
The confirmed overall response was 42.3% (95% confidence interval = 30.6%–54.6%); the complete response rate was 12.7% and partial response rate was 29.6%. Median duration of response was not reached, with 93.3% of patients having durations ≥ 6 months (range = 2.6–22.4 months, ongoing at last assessment).
Serious adverse reactions occurred in 34% of patients receiving dostarlimab-gxly. Serious adverse reactions in > 2% of patients included sepsis, acute kidney injury, urinary tract infection, abdominal pain, and pyrexia. The most common adverse reactions (≥ 20%) were fatigue/asthenia, nausea, diarrhea, anemia, and constipation. The most common grade 3 or 4 adverse reactions (≥ 2%) were anemia and increased transaminases. Immune-mediated adverse reactions can occur with the agent, including pneumonitis, colitis, hepatitis, endocrinopathies, and nephritis.
The recommended dostarlimab-gxly dose and schedule (doses 1 through 4) is 500 mg every 3 weeks. Subsequent dosing—beginning 3 weeks after dose four—is 1,000 mg every 6 weeks until disease progression or unacceptable toxicity. Dostarlimab-gxly should be administered as an intravenous infusion over 30 minutes.
