ESMO: Merck, Eisai detail Keytruda-Lenvima combo results after triple endometrial cancer OK

Data presented Sunday at ESMO helped score Merck and Eisai three global approvals for Keytruda and Lenvima in endometrial cancer. (Eisai)

BARCELONA—Regulators in three countries earlier this month green-lighted the combination of Merck’s Keytruda and Lenvima, a med Merck shares with Eisai, for certain previously treated endometrial cancer patients. And the companies are out with the expanded data that snagged them the go-aheads.

In a phase 2 study of women who aren’t candidates for surgery or radiation, the Keytruda-Lenvima pairing showed that it could spur a response in 38.9% of patients, with 7.4% of those patients showing no signs of cancer after treatment. Patients continued to benefit from treatment for a median 21.2 months, the companies said Sunday at the European Society for Medical Oncology annual meeting.

“The response rates are really quite dramatic in a group of patients that don’t really have much by way of therapeutic options,” Roy Baynes, M.D., Merck SVP and head of global clinical development, said.

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

Regulators from the U.S., Europe and Australia seemed to agree earlier this month when they simultaneously approved the combo in previously treated endometrial cancer. The indication does specify that patients must have tumors that are not microsatellite instability-high or mismatch repair deficient; Keytruda is already approved on its own to treat tumors with those features, no matter where in the body they’re located.

The approval put another feather in the cap of the Keytruda-Lenvima pairing, which the companies have thrown significant weight behind. Merck in 2017 went as far as shelling out $5.8 billion for half of Lenvima, fueled by the belief that the two drugs together could produce benefits across a variety of tumor types.

RELATED: In another blockbuster cancer deal, Merck lays out up to $5.8B for half of Eisai's Lenvima

And they’ve already shown they can do exactly that with positive trial results in cancers including liver, kidney and bladder. “The combination is clearly very active,” Baynes said, adding that the companies have 12 registrational trials planned for the duo in the front-line setting.

The companies are hoping Lenvima’s sales will spike on the back of Merck’s PD-1 superstar, but at least in endometrial cancer, it's going to take some additional data, SVB Leerink analyst Daina Graybosch predicts. "We believe an additional study of Keytruda + Lenvima with survival benefit will be necessary to reach full potential,” she wrote in a recent note to clients.