FDA grants tumor-agnostic approval to immunotherapy dostarlimab

The FDA has granted an accelerated approval to the PD-1 inhibitor dostarlimab-gxly (Jemperli) for the treatment of adult patients with mismatch repair-deficient (dMMR) recurrent or advanced solid tumors, as determined by an FDA-approved test.1

The approval provides urologists with another tool in the armamentarium for the treatment of patients with genitourinary cancers. It also underscores the rapidly growing significance of genetic testing in the field of urology.

The approval was supported by results from the ongoing phase 1 GARNET trial, which evaluated single-agent dostarlimab in patients with advanced solid tumors. The key efficacy measure was objective response rate (ORR; RECIST v 1.1 criteria), as measured by blinded independent central review.

Across 209 evaluable patients with solid tumors, the PD-1 inhibitor induced an ORR of 41.6%. The ORR was composed of a complete response rate of 9.1% and a partial response rate of 32.5%. The median duration of response was 34.7 months (range, 2.6-35.8+). Further, 95.4% of patients achieved responses of ≥6 months.

“Dostarlimab is an important new treatment option for patients with mismatch repair-deficient recurrent or advanced solid cancers who have progressed and have no alternative options. As we saw in the GARNET trial, of those patients who respond to treatment with dostarlimab, nearly all continued to respond for 6 months or longer,” Jubilee Brown, MD, professor and division director of Gynecologic Oncology at Atrium Health Levine Cancer Institute, and investigator on the GARNET study.

Safety data for dostarlimab were accrued from 267 patients in the trial. Adverse events across all grades reported in at least 20% of patients included fatigue/asthenia (42%), anemia (30%), diarrhea (25%), and nausea (22%). Grade 3/4 adverse events occurring in ≥2% of patients included anemia, fatigue/asthenia, increased transaminases, sepsis, and acute kidney injury. Grade 3/4 laboratory abnormalities occurring in ≥2% of patients included decreased lymphocytes, decreased sodium, increased alkaline phosphatase, and decreased albumin.

In a press release announcing the approval, GlaxoSmithKline, the developer of dostarlimab explained the genetic significance of mismatch repair-deficiency in cancer: “Mismatch repair-deficient tumors contain abnormalities that affect the proper repair of DNA when copied in a cell. In the United States, prevalence of dMMR across patients with solid tumors has been estimated at 14%. Mismatch repair-deficient status is a biomarker that has been shown to predict response to immune checkpoint blockade with PD-1 therapy.”

The accelerated approval of dostarlimab in dMMR solid tumors in contingent on confirmatory data from a future clinical trial.

References

1. GSK receives FDA accelerated approval for JEMPERLI (dostarlimab-gxly) for adult patients with mismatch repair-deficient (dMMR) recurrent or advanced solid tumours. Published online August 17, 2021. Accessed August 18, 2021. https://bit.ly/3zah8by.