The US Food and Drug Administration (FDA) approved pembrolizumab in combination with pemetrexed and carboplatin (PC) as a first-line treatment for patients with metastatic lung cancer, according to a press release.1

This approval is based on results from the KEYNOTE 021 study ( Identifier: NCT02039674), which showed an improved overall response rate (ORR) and progression-free survival (PFS) for pembrolizumab with PC over PC alone.

One hundred and twenty-three patients were randomly assigned to receive 200 mg pembrolizumab once every 3 weeks with 4 cycles of PC or 4 cycles of PC only. The groups were stratified by PD-L1 expression using a tumor proportion score (TPS).

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Overall, the ORR was 55% for patients receiving pembrolizumab and PC vs 29% for PC alone. Ninety-three percent of patients who responded to the experimental combination had a response duration of 6 months or longer; this figure was 81% in the PC arm.

The median PFS was 13 months for patients receiving pembrolizumab vs 8.9 months for PC.

Among patients with TPS less than 1%, ORR was 57% in the pembrolizumab group vs 13% in the PC group. For patients with TPS of least 1%, ORR was 54% for pembrolizumab with PC vs 38% for PC only, indicating the response to pembrolizumab did not depend on PD-L1 expression.

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Patients in the experimental arm had a higher rate of serious adverse events (41% vs 28% in PC arm). Ten percent of patients in the pembrolizumab arm discontinued treatment due to adverse events.

Pembrolizumab is a humanized monoclonal antibody that targets PD-1.


  1. Pembrolizumab (Keytruda) 5-10-2017 [news release]. Silver Spring, MD: US Food and Drug Administration; May 10, 2017. /ApprovedDrugs/ucm558048.htm. Accessed May 10, 2017.