GSK says Phase III Ruby trial demonstrates Jemperli plus chemotherapy potential

GSK announced interim results from Part 1 of the RUBY/ENGOT-EN6/GOG3031/NSGO phase III trial investigating Jemperli plus standard-of-care chemotherapy followed by dostarlimab compared to chemotherapy plus placebo followed by placebo in adult patients with primary advanced or recurrent endometrial cancer. Hesham Abdullah, Senior Vice President, Global Head of Oncology Development, GSK said: "These positive results from the RUBY trial bring us one step closer to addressing the significant unmet needs of endometrial cancer patients and add to the growing body of evidence on dostarlimab, strengthening our belief in its potential to transform cancer treatment as a backbone immuno-oncology therapy." A statistically significant and clinically meaningful improvement in progression free survival was observed for dostarlimab plus carboplatin-paclitaxel in the mismatch repair deficient (dMMR)/microsatellite instability-high population and in the overall population versus placebo plus chemotherapy. The separation of the lines in the Kaplan-Meier curve below illustrates the significant reduction in risk of disease progression or death in patients with dMMR/MSI-H primary advanced or recurrent endometrial cancer in the dostarlimab plus chemotherapy treatment arm compared to the placebo plus chemotherapy treatment arm. The safety and tolerability profile of dostarlimab in combination with carboplatin-paclitaxel in the RUBY phase III trial was generally consistent with the known safety profiles of the individual agents. The most common (greater than45%) treatment-emergent adverse events (TEAEs) in both treatment arms in the dMMR/MSI-H and overall populations were nausea, alopecia and fatigue, as well as anaemia in the placebo plus chemotherapy arm in the dMMR/MSI-H population. Severe and serious TEAEs were approximately 10% higher in the dostarlimab plus carboplatin-paclitaxel arm compared with the placebo plus carboplatin-paclitaxel arm in the overall population. The nature and types of immune-related adverse events (irAEs) in the dostarlimab plus chemotherapy safety profile were consistent with the mechanism of action of dostarlimab and similar to those reported for other PD-(L)1 inhibitors. In the overall population, 38.2% of participants in the dostarlimab plus carboplatin-paclitaxel arm and 15.4% of participants in the placebo plus carboplatin-paclitaxel arm had irAEs assessed by the investigator as related to dostarlimab or placebo, respectively. The most frequently reported dostarlimab-related irAE categories were endocrinopathies (15.8% dostarlimab-related versus 3.3% placebo-related) and skin adverse reactions (14.1% dostarlimab-related versus 3.7% placebo-related). Discontinuation of dostarlimab or placebo due to a TEAE occurred in 17.4% of patients in the dostarlimab plus chemotherapy treatment arm and 9.3% of patients in the placebo plus chemotherapy treatment arm in the overall population.