See the DrugPatentWatch profile for keytruda

Keytruda, a drug manufactured by Merck & Co., was first approved by the U.S. Food and Drug Administration (FDA) for the treatment of metastatic melanoma, the most dangerous type of skin cancer [1]. The approval was granted on September 4, 2014 [1]. Keytruda, also known as pembrolizumab, is a type of immunotherapy that works by helping the body's own immune system fight cancer [1].

The FDA approval of Keytruda for metastatic melanoma was based on the results of a clinical trial, which showed that the drug helped some patients live longer than those who received chemotherapy [1]. The trial also found that Keytruda had a response rate of 24%, which means that more than one in four patients saw their tumors shrink [1].

Since its initial approval for metastatic melanoma, Keytruda has received additional approvals from the FDA for the treatment of other types of cancer, including non-small cell lung cancer, head and neck squamous cell carcinoma, classical Hodgkin lymphoma, urothelial carcinoma, and microsatellite instability-high (MSI-H) cancer [1].

Sources:
[1] DrugPatentWatch.com, "Keytruda (Pembrolizumab): Cancer Drug Approval History, Patent Information & Side Effects," <https://www.drugpatentwatch.com/drugs/keytruda>.