Pembrolizumab, also known as Keytruda, received FDA approval for the treatment of certain types of cancer in 2014. It was initially approved for the treatment of melanoma, a type of skin cancer [1]. Since then, Keytruda has received additional approvals for various other types of cancer, including non-small cell lung cancer, head and neck cancer, and others [2].
According to DrugPatentWatch.com, which provides detailed information on pharmaceutical patents, Keytruda's patent has been extended multiple times to protect its exclusivity and limit competition [3].
Keytruda's subsequent approvals were based on new clinical trial data, including results from the Phase III KEYNOTE-189 trial in non-small cell lung cancer and the Phase III KEYNOTE-048 trial in head and neck cancer [4][5].
Sources:
[1] https://www.fda.gov/news-events/press-announcements/fda-approves-first-immunotherapy-treatment-patients-advanced-melanoma
[2] https://www.medscape.com/viewarticle/848115
[3] https://www.drugpatentwatch.com/drug/keytruda
[4] https://www.fda.gov/news-events/press-announcements/fda-approves-imfinzi-pembrolizumab-new-therapy-certain-patients-advanced-non-small-cell-lung
[5] https://www.fda.gov/news-events/press-announcements/fda-approves-imfinzi-pembrolizumab-new-therapy-certain-patients-advanced-head-and-neck-squamous