Keytruda is a medication used to treat various types of cancer. According to Drug Patent Watch [1], Keytruda is manufactured by Merck Sharp & Dohme Corp. The patent for Keytruda is owned by Merck & Co., Inc. [1][2]. In December 2022, Reuters reported that Merck & Co., Inc. could keep its patent edge by shifting Keytruda cancer drug to a simple shot [2]. The article explains that Merck & Co., Inc. has been exploring new ways to administer Keytruda, including a new delivery method that could potentially extend the drug's patent protection. According to a study published in the National Center for Biotechnology Information [3], Keytruda is a monoclonal antibody that targets the programmed death receptor-1 (PD-1) pathway. It has been shown to be effective in treating a variety of cancers, including melanoma, non-small cell lung cancer, and head and neck squamous cell carcinoma.

Sources:
[1] https://www.drugpatentwatch.com/p/biologics/tradename/KEYTRUDA
[2] https://www.reuters.com/business/healthcare-pharmaceuticals/merck-could-keep-its-patent-edge-by-shifting-keytruda-cancer-drug-simple-shot-2022-12-02/
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5798424/