Once conditional, Merck's Keytruda, Eisai's Lenvima win full approval for endometrial cancer

It’s official. Nearly two years after the FDA granted conditional approval to Merck’s Keytruda and Eisai’s Lenvima for endometrial cancer, the U.S. regulator has blessed the combination therapy, with no strings attached.

The green light converts the companies' accelerated approval to a full approval for endometrial cancer that’s not microsatellite instability high (MSI-H) or mismatch repair deficient (dMMR) and for patients whose tumors have progressed following prior treatment.

RELATED: Merck, Eisai’s Keytruda-Lenvima combo wins simultaneous OKs in U.S., Canada and Australia

There are limited treatment options for the disorder. Women with advanced endometrial cancer who are not candidates for curative therapy have a survival rate of just 17%

"This approval is an important step forward in helping patients fight this difficult-to-treat malignancy, as physicians can now provide an option that may improve survival outcomes.” Dr. Vicky Makker of the Memorial Sloan Kettering Cancer Center said in a release.

It is the 33rd FDA approval for Keytruda since the anti-PD-1 drug won its first nod in 2014 for advanced melanoma. It is the fifth for Lenvima since it’s go-ahead for differentiated thyroid cancer in 2015. Lenvima is an oral multiple receptor tyrosine kinase inhibitor. 

The endorsement comes after a phase 3 trial showed that Keytruda and Lenvima cut the risk of death by 38% over chemotherapy in patients with previously treated endometrial cancer regardless of their tumor’s mismatch repair status.

Patients on the combo lived a median 18.3 months, while chemo patients survived for a median of 11.4 months. The cocktail also reduced the risk of the disease worsening by 44% in all comers. In the mismatch repair proficient subgroup, Keytruda and Lenvima reduced the risk of death by 32% and disease worsening by 40%. 

The approval is significant considering the FDA’s recent examination of immuno-oncology agents such as Keytruda that have been able to keep their variety of indications approved under the accelerated pathway even after failing confirmatory trials.   

The increased scrutiny convinced Merck to withdraw Keytruda approvals in third-line stomach cancer and third-line small cell lung cancer. The company, however, despite trial failures, has continued to stand behind Keytruda in newly diagnosed bladder cancer patients ineligible for cisplatin-based chemotherapy and second-line liver cancer.   

RELATED: Merck, Eisai detail Keytruda and Lenvima’s endometrial cancer win in confirmatory study

The Keytruda-Lenvima combo is on track for another approval, this one for previously untreated renal cell carcinoma.

While it is alone in the endometrial cancer market, there are many other options in kidney cancer including Keytruda’s pairing with Pfizer’s Inlyta, Bristol Myers Squibb’s combo of Opdivo and Yervoy and an Opdivo pairing with Exelixis’ Cabometyx.