Phathom Pharmaceuticals, is a US biopharmaceutical company focused on the development and commercialization of novel treatments for gastrointestinal (GI) diseases and disorders. Takeda has granted a license to Phathom for the development and exclusive commercialization rights to vonoprazan in the United States, Europe and Canada. Vonoprazan is a novel, orally active potassium competitive acid blocker (P-CAB) discovered and developed by Takeda and marketed by both Takeda and Otsuka in Japan since 2015. P-CABs are a class of drug that competitively block the potassium-binding site of gastric hydrogen potassium ATPase (also known as the proton pump). Phathom is listed on the NASDAQ with the ticker PHAT.