GSK plc today announced the European Commission has approved dostarlimab in combination with chemotherapy (carboplatin and paclitaxel) for first-line treatment of adult patients with primary advanced or recurrent endometrial cancer who are candidates for systemic therapy.

This approval broadens the previous indication for dostarlimab plus chemotherapy in the European Union (EU) to include patients with mismatch repair proficient (MMRp)/microsatellite stable (MSS) tumours, which represent approximately 75% of patients diagnosed with endometrial cancer and who have limited treatment options.

Hesham Abdullah, Senior Vice President, Global Head Oncology, R&D, GSK, said: “For the first time, all patients with primary advanced or recurrent endometrial cancer in the EU have an approved immuno-oncology based treatment that has shown a statistically significant and clinically meaningful overall survival benefit.

We’re proud dostarlimab continues to redefine the treatment landscape for patients.” Dr Mansoor Raza Mirza, Chief Oncologist, Copenhagen University Hospital, Denmark, and RUBY principal investigator said: “Clinicians have been waiting for years for an immuno-oncology-based option that can meaningfully improve overall survival outcomes for patients with MMRp/MSS primary advanced or recurrent endometrial cancer.

The expanded approval represents a significant advance that delivers on this hope, now for patients with both dMMR/MSI-H and MMRp/MSS tumours.” The European Commission’s approval to expand the use of dostarlimab plus chemotherapy is based on results from Part 1 of the RUBY phase III trial.

RUBY Part 1 is the only clinical trial in this setting to show a clinically meaningful and statistically significant overall survival (OS) benefit in the full population of patients with primary advanced or recurrent endometrial cancer, demonstrating a 31% reduction in risk of death (HR: 0.69; 95% CI: 0.54–0.89) compared to chemotherapy alone.

At the 2.5-year landmark, the chance of being alive was 61% (95% CI: 54-67) for patients in the dostarlimab plus chemotherapy group (245 patients) compared to 49% (95% CI: 43-55) in the chemotherapy group (249 patients). In addition, a 16.4-month improvement in median OS was observed with Jemperli plus chemotherapy versus chemotherapy alone (44.6 months [95% CI: 32.6–NR] vs. 28.2 months [95% CI: 22.1–35.6], respectively).

The median duration of follow-up was more than three years. The safety and tolerability analysis from RUBY Part 1 showed a safety profile for dostarlimab plus carboplatin-paclitaxel that was generally consistent with the known safety profiles of the individual agents.

The most common treatment-emergent adverse reactions (≥ 10%) in patients receiving dostarlimab plus chemotherapy were rash, rash maculopapular, hypothyroidism, pyrexia, alanine aminotransferase increased, aspartate aminotransferase increased and dry skin.

OS data were presented at the Society of Gynecologic Oncology Annual Meeting on Women’s Cancer on 16 March 2024, and were published in Annals of Oncology on 9 June 2024. The label for dostarlimab plus chemotherapy in the US was expanded to all adult patients with primary advanced or recurrent endometrial cancer in August 2024.

Source: GSK