On August 17, 2021, the Food and Drug Administration granted accelerated approval to dostarlimab-gxly for adult patients with mismatch repair deficient (dMMR) recurrent or advanced solid tumors, as determined by an FDA-approved test, that have progressed on or following prior treatment and who have no satisfactory alternative treatment options.

Today, the FDA also approved the VENTANA MMR RxDx Panel as a companion diagnostic device to select patients with dMMR solid tumours for treatment with dostarlimab-gxly.

The efficacy of dostarlimab was evaluated in the GARNET Trial (NCT02715284), a non-randomised, multicenter, open-label, multi-cohort trial.

The efficacy population consisted of 209 patients with dMMR recurrent or advanced solid tumours who progressed following systemic therapy and had no satisfactory alternative treatment.

The primary efficacy endpoints were overall response rate (ORR) and duration of response (DoR) as determined by blinded independent central review according to RECIST 1.1.

The ORR was 41.6% (95% CI: 34.9, 48.6), with 9.1% complete response rate and 32.5% partial response rate. Median DOR was 34.7 months (range 2.6, 35.8+), with 95.4% of patients with duration ≥6 months.

Most common adverse reactions (≥20%) in patients with dMMR solid tumours are fatigue /asthenia, anaemia, diarrhoea, and nausea.

Most common Grade 3 or 4 adverse reactions (≥2%) were anaemia, fatigue/asthenia, increased transaminases, sepsis, and acute kidney injury.

Immune-mediated adverse reactions are also associated with dostarlimab-gxly including pneumonitis, colitis, hepatitis, endocrinopathies, nephritis and dermatologic toxicity.

The recommended dostarlimab dosage is 500 mg every 3 weeks for dose 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.

View full prescribing information for dostarlimab-gxly here.

Source: FDA