On August 17, the U.S. Food and Drug Administration (FDA) granted accelerated approval to dostarlimab-gxly (Jemperli), an anti–PD-1 antibody, for adult patients with mismatch repair–deficient (dMMR) recurrent or advanced solid tumors, as determined by an FDA-approved test, who have had disease progression on or following prior treatment and who have no satisfactory alternative treatment options.
The FDA also approved the Ventana MMR RxDx Panel as a companion diagnostic device to select patients with dMMR solid tumors for treatment with dostarlimab-gxly.
The efficacy of dostarlimab was evaluated in the GARNET trial (ClinicalTrials.gov identifier NCT02715284), a nonrandomized, multicenter, open-label, multicohort trial. The efficacy population consisted of 209 patients with dMMR recurrent or advanced solid tumors whose disease progressed following systemic therapy and had no satisfactory alternative treatment.
The primary efficacy endpoints were overall response rate and duration of response as determined by blinded independent central review according to Response Evaluation Criteria in Solid Tumors version 1.1. The overall response rate was 41.6% (95% confidence interval [CI] = 34.9%–48.6%), with a 9.1% complete response rate and a 32.5% partial response rate. Median duration of response was 34.7 months (range = 2.6–35.8+ months), with 95.4% of patients having a duration of response lasting 6 months or longer.
The most common adverse reactions (≥ 20%) to dostarlimab in patients with dMMR solid tumors are fatigue/asthenia, anemia, diarrhea, and nausea. The most commonly reported grade 3 or 4 adverse reactions (≥ 2%) were anemia, fatigue/asthenia, increased transaminases, sepsis, and acute kidney injury. Immune-mediated adverse reactions are also associated with dostarlimab, including pneumonitis, colitis, hepatitis, endocrinopathies, nephritis, and dermatologic toxicity.
The recommended dostarlimab dosage is 500 mg every 3 weeks for doses 1 through 4, as an intravenous infusion over 30 minutes. Subsequent dosing beginning 3 weeks after dose 4 is 1,000 mg every 6 weeks.
This indication is approved under accelerated approval based on tumor response rate and durability of response. Continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial(s).