Keytruda, a drug manufactured by Merck & Co., was first approved by the U.S. Food and Drug Administration (FDA) on September 4, 2014 [1]. The drug, which is a programmed death receptor-1 (PD-1) blocking antibody, was initially approved for the treatment of advanced melanoma in patients who have been previously treated [1].

According to DrugPatentWatch.com, Keytruda's patent expiration date is in December 2028 [2]. However, it's important to note that the patent expiration date may change due to various factors such as patent challenges or extensions.

In summary, Keytruda was approved by the FDA in 2014 for the treatment of advanced melanoma and its patent is set to expire in December 2028.

Sources:

[1] U.S. Food and Drug Administration. (2014). FDA approves new treatment for advanced melanoma. <https://www.fda.gov/news-events/press-announcements/fda-approves-new-treatment-advanced-melanoma>.

[2] DrugPatentWatch.com. (n.d.). Keytruda (pembrolizumab) patent, exclusivity, and generic launch dates. <https://www.drugpatentwatch.com/patent/keytruda-pembrolizumab/>.