GSK’s Jemperli (dostarlimab) plus chemotherapy approved in Singapore as the first frontline immuno-oncology treatment for dMMR/MSI-H primary advanced or recurrent endometrial cancer

GSK Singapore announced that the Singapore Health Sciences Authority (HSA) has approved a new indication for Jemperli (dostarlimab), which may now be used in combination with carboplatin and paclitaxel, followed by Jemperli as a single agent for the treatment of adult patients with primary advanced or recurrent endometrial cancer that is mismatch repair deficient (dMMR) or microsatellite instability-high (MSI-H).

With this approval, Jemperli is now indicated earlier in treatment, in combination with chemotherapy, for patients with dMMR/MSI-H primary advanced or recurrent endometrial cancer. Jemperli has earlier received approval from Singapore HSA as a monotherapy in adult patients with dMMR recurrent or advanced endometrial cancer that has progressed on or following a prior platinum-containing regimen in any setting and are not candidates for curative surgery or radiation.

Latest Singapore Cancer Registry, from 2017-2021, reported endometrial cancer as the fourth most common and had the ninth highest cancer mortality rate among females in the country, with 3,133 new cases diagnosed during the period. Approximately 15-20% of endometrial cancer patients globally and 28% in Singapore were at advanced disease stage at the time of diagnosis. An estimated 20-29% of all endometrial cancers globally are dMMR/MSI-H. Chemotherapy used alone has been the current standard of care for primary advanced or recurrent endometrial cancer, and many patients eventually experience disease progression.

Dr. Stephanie Cinthu Stephen Ambrose, GSK Singapore Medical Director, said: “Singapore’s expanded regulatory approval of Jemperli redefines the treatment landscape for patients with dMMR/MSI-H primary advanced or recurrent endometrial cancer in Singapore. Until now, chemotherapy alone has been the standard of care with many patients experiencing disease progression. In GSK’s RUBY trial, Jemperli plus chemotherapy demonstrated a 72% reduction in the risk of disease progression or death versus chemotherapy in this patient population, providing a statistically significant and clinically meaningful benefit. These results underscore the potential for Jemperli to transform cancer treatment as a backbone immuno-oncology therapy.”

Dr. John Chia of Curie Oncology, Singapore, said: “Metastatic endometrial cancer is an aggressive disease with poor outcomes, and doctors sometimes struggle with limited effective treatment options. The results of the RUBY trial represent a clinical breakthrough in decades for dMMR/MSH-I endometrial cancer (or commonly known as uterine cancer). With this new approved treatment combination, many patients with primary advanced or recurrent dMMR endometrial cancer in Singapore will now have an opportunity for potential complete remission, with maximal benefit when given early in the treatment.”

GSK’s submission to the Singapore’s regulatory body included interim analysis results from Part 1 of the RUBY/ENGOT-EN6/GOG3031/NSGO Phase III trial, which reflect a robust median duration of follow-up of ≥ 25 months. The trial met the primary endpoint of investigator-assessed progression-free survival (PFS), demonstrating a statistically significant and clinically meaningful benefit in patients treated with Jemperli plus carboplatin and paclitaxel in the dMMR/MSI-H population. In the dMMR/MSI-H population, a 72% reduction in the risk of disease progression or death was observed.

The safety and tolerability profile for Jemperli plus carboplatin and paclitaxel was generally consistent with the known safety profiles of the individual agents. The most common treatment-emergent adverse events (≥ 20%) in patients receiving Jemperli plus chemotherapy were rash, diarrhoea, hypothyroidism, and hypertension.