Jemperli Approved in Singapore for First-Line Treatment of Advanced or Recurrent Endometrial Cancer with dMMR/MSI-H

On August 7, 2023, GlaxoSmithKline (GSK.US) Singapore announced that the Health Sciences Authority of Singapore (HSA) has approved a new indication for Jemperli (dostarlimab). This approval signals that Jemperli can be used in combination with carboplatin and paclitaxel and subsequently as a single agent to treat patients with primary advanced or recurrent endometrial cancer, particularly those with mismatch repair defects (dMMR) or high microsatellite instability (MSI-H). Jemperli is a programmed death receptor-1 (PD-1) blocking antibody that binds to the PD-1 receptor and blocks its interaction with the PD-L1 and PD-L2 ligands.

According to a GSK press release, the approval makes Jemperli the first first-line immuno-oncology therapy in Singapore for the treatment of primary advanced or recurrent endometrial cancer of dMMR/MSI-H, suitable for the early treatment of such patients. Jemperli has previously been approved by the HSA Singapore for the treatment of adult patients with recurrent or advanced endometrial cancer of dMMR who have progressed during or after prior platinum-containing treatment regimens and are not suitable for therapeutic surgery or radiotherapy.

Jemperli is a humanized anti-PD-1 monoclonal antibody developed by GSK and approved by the U.S. Food and Drug Administration (FDA) in 2021 for the treatment of patients with advanced solid tumors lacking mismatch repair (dMMR) or microsatellite highly unstable (MSI-H).

In March 2023, the FDA approved Jemperli for the treatment of recurrent or metastatic endometrial cancer as the preferred chemotherapy regimen, in combination with carboplatin and paclitaxel. This was a new indication for Jemperli.

In the all-important Phase III RUBY clinical trial, Jemperli combined chemotherapy significantly extended progression-free survival compared to chemotherapy alone (carboplatin + paclitaxel). Specifically, the median progression-free survival reached 18.4 months in the Jemperli combination group, compared to 10.8 months in the chemotherapy monotherapy group. These results demonstrate that the Jemperli combined chemotherapy regimen provided significant clinical benefit for patients with recurrent or metastatic endometrial cancer.

In addition, Jemperli combined chemotherapy demonstrated its superiority in terms of response rate. The overall response rate was as high as 56.5%, a significant improvement compared to 42.3% in the chemotherapy monotherapy group. This data further validates the effectiveness and potential of this treatment regimen.

It is important to note that the safety of Jemperli combined chemotherapy was also validated and no new safety signals were found. Dr Stephanie Cinthu Stephen Ambrose, Medical Director, GSK Singapore, said: "Singapore's expanded regulatory approval for Jemperli redefines the treatment landscape for patients with primary advanced or relapsed dMMR/MSI-H endometrial cancer in Singapore. To date, chemotherapy has been the standard treatment for many patients with progressive disease. In the GSK RUBY trial, Jemperli+ chemotherapy showed a 72% reduction in the risk of disease progression or death compared to chemotherapy in this patient population, providing a statistically significant and clinically significant benefit. These results underscore Jemperli's potential to transform cancer therapy into a backbone immunotumor therapy."