Keytruda, a drug developed by Merck & Co., was first approved by the U.S. Food and Drug Administration (FDA) for cancer therapy in September 2014 [1]. The drug, which is a programmed death receptor-1 (PD-1) blocking antibody, was initially approved for the treatment of advanced melanoma [1].

Since its initial approval, Keytruda has received additional approvals from the FDA for the treatment of various 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].

It is worth noting that, according to DrugPatentWatch.com, Keytruda's patent is set to expire in 2028 [2]. This information could be relevant for patients, healthcare providers, and pharmaceutical companies, as the expiration of a drug's patent often leads to the availability of cheaper generic versions of the drug [3].

In summary, Keytruda was first approved by the FDA for cancer therapy in September 2014 and has since received additional approvals for the treatment of various types of cancer. Keytruda's patent is set to expire in 2028.

Sources:

1. [FDA approves Merck’s Keytruda (pembrolizumab) for first-line treatment of patients with advanced non-small cell lung cancer (NSCLC) with PD-L1 expression](https://www.fda.gov/news-events/press-announcements/fda-approves-mercks-keytruda-pembrolizumab-first-line-treatment-patients-advanced-non)
2. [Keytruda (pembrolizumab) Pipeline & Patent Expiry Date](https://www.drugpatentwatch.com/drugs/keytruda)
3. [Drug Patents and Generics](https://www.fda.gov/drugs/development-approval-process-drugs/drug-patents-and-generics)