NEW YORK – The Phase III Keynote-775 trial, evaluating the combination of Merck's pembrolizumab (Keytruda) and Eisai's lenvatinib (Lenvima) in previously treated, advanced endometrial cancer patients, met its primary endpoints of overall and progression-free survival, the companies said on Wednesday.
The combination of pembrolizumab and lenvatinib improved overall survival and progression-free survival in both the mismatch repair proficient (pMMR) subgroup and the entire study population, when compared to physician's choice of doxorubicin or paclitaxel chemotherapy. Merck and Eisai intend to discuss this data with regulators and submit marketing authorization applications based on these results.
The study enrolled 827 advanced endometrial cancer patients who had received at least one prior platinum-based regimen. Within that group, 130 patients had tumors that were microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) and 697 had tumors that were not MSI-H or MMR proficient (pMMR).
"Women with advanced endometrial cancer are faced with high mortality rates and limited treatment options following initial systemic therapy," Gregory Lubiniecki, associate VP of oncology clinical research at Merck Research Laboratories, said in a statement. "These are the first results from a Phase III trial of a combination regimen including immunotherapy in advanced endometrial carcinoma that have shown a statistically significant improvement in overall survival, progression-free survival, and objective response rate versus chemotherapy."
Keynote-775 was a confirmatory trial of the Phase Ib/II Keynote-146 trial that supported the US Food and Drug Administration's accelerated approval in 2019 of pembrolizumab and lenvatinib to treat advanced endometrial cancer patients who are not MSI-H or dMMR, who have progressed on other systemic therapy and cannot have surgery or radiation. That approval was granted under the FDA's Project Orbis, which enables concurrent review of oncology drugs among international partners. Health Canada and Australia's Therapeutic Goods Administration also granted conditional approval to the combination in this setting.
Merck and Eisai are studying the pembrolizumab and lenvatinib combination in 13 different tumor types across 20 clinical trials through the LEAP (LEnvatinib And Pembrolizumab) clinical program. The companies plan to present data from Keynote-775 at an upcoming medical conference.