GSK plc (LSE: GSK) (NYSE: GSK) announced on Monday that the European Commission has expanded the approval of Jemperli (dostarlimab) in combination with chemotherapy (carboplatin and paclitaxel) for the first-line treatment of adult patients with primary advanced or recurrent endometrial cancer. This approval now includes patients with mismatch repair proficient (MMRp)/microsatellite stable (MSS) tumours, which account for approximately 75% of endometrial cancer cases.

The approval is based on data from the RUBY Part 1 Phase III trial, which demonstrated a 31% reduction in the risk of death for patients receiving Jemperli plus chemotherapy compared to chemotherapy alone (HR: 0.69). The median overall survival (OS) was 44.6 months for the combination treatment group, compared to 28.2 months for chemotherapy alone.

Jemperli plus chemotherapy is the first immuno-oncology treatment to show a statistically significant OS benefit in this patient population. The safety profile of the combination was consistent with previous studies, with common adverse reactions including rash, hypothyroidism, and pyrexia.

The RUBY trial, which enrolled 785 patients globally, continues to evaluate the efficacy of Jemperli in combination with chemotherapy and other therapies in endometrial cancer. Jemperli is already approved in the US for the treatment of primary advanced or recurrent endometrial cancer in both MMRp/MSS and dMMR/MSI-H tumour patients.

This expanded approval positions Jemperli as a key treatment option for a larger patient population with advanced endometrial cancer, a disease with rising incidence rates worldwide. GSK continues to advance its immuno-oncology research, with ongoing studies in various cancers.