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As FDA scrutinizes immunotherapy approvals, Merck says Keytruda extends survival in liver cancer trial

The FDA has been under pressure to review the status of drugs granted accelerated approvals based on early data, as in some cases confirmatory trials haven’t been completed or those studies failed to prove a patient benefit.

The issue has been particularly troublesome in cancer and rare disease research, where a rush of new treatments and desperately ill patients have tilted the FDA’s usual calculations in favor of early approvals.

Still, the past few months have seen withdrawals of Keytruda and similar immunotherapies like Bristol Myers Squibb’s Opdivo, Roche’s Tecentriq and AstraZeneca’s Imfinzi in certain cancer types and settings. Bristol Myers, for example, pulled Opdivo as a single therapy in liver cancer following a negative advisory committee vote, although it continues to market the drug in combination with another immunotherapy, Yervoy. An accelerated approval of that combination is also subject to confirmatory trials.

In addition, the agency has called for another advisory committee meeting to review the status of two older drugs, Farydak and Marqibo.

Merck should now be able to use the KEYNOTE-394 results to ask the FDA for a full approval. In addition to showing Keytruda helped study participants live longer, KEYNOTE-394 found a statistically significant benefit on progression-free survival and on helping patients achieve remission, Merck said.

Without data, it is unclear exactly how Keytruda monotherapy compares with other drugs recommended in this setting, especially because it was compared only to a placebo along with supportive treatments aimed at relieving pain and disease complications. In second-line treatment, Exelixis’ Cabometyx and Eli Lilly’s Cyramza have been approved after first-line treatment with Nexavar, and those two drugs reduced the risk of death by 24% and 29%, respectively.

Merck says its research continues in liver cancer, too, pointing to seven clinical trials that have enrolled 3,000 patients, testing Keytruda both as a single agent and in combination with other drugs.