Following a meeting with the Food and Drug Administration (FDA), Merck is voluntarily withdrawing the US indication for Keytruda® (pembrolizumab) for the treatment of patients with metastatic small cell lung cancer (SCLC) with disease progression on or after platinum-based chemotherapy and at least 1 other prior line of therapy.

In June 2019, the FDA granted accelerated approval to Keytruda for metastatic SCLC based on data from the KEYNOTE-158 ( NCT02628067) and KEYNOTE-028 ( NCT02054806) trials, which showed positive tumor response rates and durability of responses. According to the FDA’s accelerated approval program, a drug may be approved earlier if it is intended to treat a serious condition or fills an unmet need; the approval is based on a surrogate end point that is thought to predict clinical benefit.

However, findings from a subsequent confirmatory phase 3 trial (KEYNOTE-604; NCT03066778) showed that the study met 1 of its dual primary end points of progression-free survival but did not reach statistical significance for the other primary end point of overall survival. Continued approval of the indication was contingent upon establishing the superiority of Keytruda as determined by overall survival.

Merck is notifying health care professionals regarding the withdrawal of the US indication. Patients with metastatic SCLC who are being treated with Keytruda should consult with their health care provider.


Merck provides update on Keytruda® (pembrolizumab) indication in metastatic small cell lung cancer in the US. [press release]. Kenilworth, NJ: Merck; March 1, 2021.