FDA approves dostarlimab companion diagnostic for use across dMMR solid tumors

The FDA has approved the Ventana MMR RxDx Panel test as a companion diagnostic to help identify patients with advanced solid tumors that are mismatch repair deficient (dMMR), in order to determine eligibility for the newly approved immunotherapy dostarlimab-gxly (Jemperli).1

Ventana MMR RxDx Panel is a qualitative immunohistochemistry test that assesses a panel of MMR proteins to help guide clinicians in theirtreatment decisions.

"As the first companion diagnostic of its kind, this test can help qualify patients with solid tumors that are deficient in MMR who have progressed in their disease and who have no other suitable treatment options,” Thomas Schinecker, CEO of Roche Diagnostics, the developer of the Ventana MMR RxDx Panel, stated in a press release. “Based on the results of our MMR biomarker test, these patients may be eligible to receive GSK’s Jemperli. We are pleased that our innovative companion diagnostic label continues to grow to serve more patients.”

The FDA approved the PD-1 inhibitor dostarlimab-gxly (Jemperli) on August 17, 2021, for the treatment of adult patients with dMMR recurrent or advanced solid tumors, as determined by an FDA-approved test.2

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.

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.

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

References

1. Roche receives FDA approval for first companion diagnostic to identify dMMR solid tumour patients eligible for anti-PD-1 immunotherapy. Published online August 18, 2021. Accessed August 19, 2021. https://bit.ly/3mdKbaI.

2. 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.