Merck and Eisai have reported investigational data from the pivotal Phase III KEYNOTE-775/Study 309 trial of anti-PD-1 therapy Keytruda (pembrolizumab) plus Lenvima (lenvatinib) for treating patients with advanced, metastatic or recurrent endometrial cancer following a platinum-based regimen.

Ketruda is Merck’s humanised monoclonal antibody while Lenvima is an orally available multiple receptor tyrosine kinase inhibitor discovered by Eisai.

Starting in the inner lining of the uterus or endometrium, endometrial cancer is the most common type of cancer in the uterus.

The multi-centre, randomised, open-label trial analysed Keytruda plus Lenvima in subjects with advanced endometrial cancer following one prior platinum-based regimen in any setting.

It enrolled 827 subjects who were randomised in a 1:1 ratio. They received either Keytruda 200mg intravenously every three weeks for up to 35 cycles plus Lenvima 20mg orally once daily or chemotherapy treatment of physician’s choice (TPC).

Data showed that the trial met the dual primary endpoints of progression-free survival (PFS) and overall survival (OS).

It also met the secondary efficacy endpoint of objective response rate (ORR) in the all-comer population (mismatch repair proficient [pMMR] and mismatch repair deficient [dMMR]) and the pMMR subgroup.

Furthermore, the combination treatment provided statistically significant and clinically meaningful improvement in OS in the all-comer population by reducing the risk of death by 38%, with a median OS of 18.3 months versus 11.4 months for those receiving chemotherapy.

Merck Research Laboratories oncology clinical research vice-president Dr Gregory Lubiniecki said: “In this confirmatory Phase III study, Keytruda plus Lenvima demonstrated statistically significant improvements in progression-free survival, overall survival and objective response rate versus chemotherapy.

“We are encouraged by these results that reaffirm Merck’s and Eisai’s commitment to exploring the potential of the combination to help more patients with difficult-to-treat types of cancer.”