Merck suits up for another Opdivo showdown with Keytruda liver cancer approval

Merck just advanced the Keytruda-Opdivo immuno-oncology rivalry into a brand-new arena.

On Friday, the FDA handed Keytruda a new approval in patients with hepatocellular carcinoma—the most common form of liver cancer in adults—who have already been treated with Bayer’s Nexavar. That’s a group for which regulators cleared Opdivo, Keytruda’s chief nemesis in the PD-1/PD-L1 class, last September.

The agency based its decision on results from a phase 2 trial that showed Keytruda could provoke a response in 17% of patients. Among responders, 89% of patients felt the benefits of therapy for six months or more, and 56% experienced them for a year or more.

While 17% may sounds like a small percentage, it’s not far behind the 18.2% response rate Opdivo drove en route to its own approval in Nexavar-treated patients. And now, the two will go head-to-head in yet another patient population, adding liver cancer to a list that already includes melanoma, lung cancer and others.

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“While we have seen recent therapeutic advancements, there are still limited treatment options for advanced recurrent disease,” Andrew Zhu, M.D., lead investigator for the Merck study, said in a statement, calling Keytruda’s approval “important.”

The thing is, Keytruda and Opdivo—despite being the only two I-O therapies approved for liver cancer patients—aren’t alone on the liver cancer battleground. Bayer, which has long reigned supreme in the disease area thanks to immense success with Nexavar, last year landed a second-line nod for follow-up drug Stivarga. Since then, it’s been working to bill the duo as a regimen, encouraging doctors to keep prescriptions in the family after patients fail on Nexavar.

Merck, though, already has some familiarity with the liver cancer market thanks to an August approval for Lenvima, an Eisai drug in which the New Jersey drugmaker nabbed a 50% stake this March. Lenvima scored a go-ahead in previously untreated patients, setting it up to square off with Nexavar.