Blockbuster Keytruda earns new breast cancer indication

FDA approved a new indication for Merck’s blockbuster cancer drug, pembrolizumab (Keytruda), in combination with chemotherapy, to treat locally recurrent unresectable or metastatic triple-negative breast cancer (TNBC).

Sales of Keytruda, approved to treat several different types of cancer including non-small-cell lung cancer, soared 21%, to $3.7 billion, in the third quarter of 2020.

Related: Merck’s Keytruda snags another cancer indication​

“Today’s approval is a significant milestone, as it represents the first approval for Keytruda in the breast cancer setting,” said Roy Baynes, M.D., senior vice president and head of global clinical development, chief medical officer of Merck Research Laboratories, in a press release.

Roy Baynes

In the phase 3 trial supporting the approval, Keytruda in combination with paclitaxel, nab-paclitaxel or gemcitabine and carboplatin, significantly improved progression-free survival for patients with advanced triple-negative breast cancer whose tumors express PD-L1 with combined positive score (CPS) greater than or equal to 10 compared with the same chemotherapy regimens alone, Baynes added.

Keytruda, in combination with the chemotherapy agents, reduced the risk of disease progression or death by 35% for patients whose tumors express PD-L1 versus the same chemotherapy regimens alone

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The multicenter, double-blind, randomized, placebo-controlled trial included 847 patients with locally recurrent unresectable or metastatic TNBC, regardless of tumor PD-L1 expression, who had not been previously treated with chemotherapy in the metastatic setting.

FDA granted accelerated approval for the indication based on progression-free survival (PFS), so continued approval for that indication may be contingent upon verification and description of clinical benefit in the confirmatory trials, Merck said.

“Approximately 15 to 20% of patients with breast cancer are diagnosed with triple-negative breast cancer, which is a difficult-to-treat and aggressive cancer,” said Dr. Hope Rugo, director of Breast Oncology and Clinical Trials Education, University of California San Francisco Helen Diller Family Comprehensive Cancer Center. “The approval of Keytruda in combination with chemotherapy gives physicians an important new option for appropriate patients.”

Read more: FDA clears novel breast cancer drug​