FDA expands Merck & Co.'s Keytruda for use in PD-L1-positive NSCLC

The FDA on Friday granted accelerated approval for Merck & Co.'s anti-PD-1 therapy Keytruda (pembrolizumab), broadening its indication to include patients with PD-L1-positive non-small-cell lung cancer (NSCLC) whose disease progressed after prior treatment. The drug was approved for use along with Agilent Technologies' PD-L1 IHC 22C3 pharmDx companion diagnostic, which the agency said is the first test designed to detect PD-L1 expression in NSCLC tumours. Richard Pazdur, director of the Office of Hematology and Oncology Products in the FDA's Center for Drug Evaluation and Research, remarked "today's approval of Keytruda gives physicians the ability to target specific patients who may be most likely to benefit from this drug."

Merck said the decision was based on data from the Phase Ib KEYNOTE-001 study, which evaluated Keytruda in 280 patients with metastatic NSCLC that had progressed following platinum-containing chemotherapy, and if appropriate, targeted therapy for EGFR or ALK mutations. A subgroup of 61 patients also had PD-L1 positive tumours based on results of the 22C3 pharmDx diagnostic test. Results showed that Keytruda was associated with an overall response rate of 41 percent in patients with a PD-L1 expression tumour proportion score of at least 50 percent, and the effect lasted between 2.1 months and 9.1 months. Merck noted that of the patients who responded, 84 percent continued to respond to treatment with Keytruda, including 11 patients with ongoing responses of six months or longer.

Keytruda had been granted priority review and breakthrough therapy status by the FDA for theNSCLC indication. The therapy was already approved for the treatment of advanced or unresectable melanoma, becoming the first PD-1 inhibitor to win marketing authorisation in the US.

Meanwhile, Bristol-Myers Squibb's PD-1 inhibitor Opdivo (nivolumab) was granted accelerated approval by the FDA last December for the treatment of melanoma, while its indication was subsequently expanded to include advanced squamous NSCLC in certain patients, but without the need for patients to show significant levels of PD-L1. The drug was approved earlier this week in combination with Yervoy (ipilimumab) for patients with BRAF V600 wild-type unresectable or metastatic melanoma. (For related analysis see ViewPoints: Bristol-Myers Squibb pushes first immuno-oncology combination past the approval post but will it prove a game-changer in melanoma?)

Analysts have projected annual sales in excess of $20 billion for the PD-1 inhibitor class by 2020.

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