Mechanism of Action

Vonoprazan, an investigational potassium competitive acid blocker (P-CAB) in late clinical-stage development for the treatment of gastric acid-related disorders



  • Does not require activation by gastric acid
  • Quickly blocks active and inactive acid pumps
  • Is stable in the presence of acid
  • Has a long plasma half-life

Vonoprazan’s characteristics allow for more rapid and potent acid suppression versus the PPI esomeprazole in human subjects two hours after oral dosing and maintain target acid inhibition over a 24-hour period.

Vonoprazan was developed in markets outside of the United States through an extensive clinical program, including 19 Phase 3 clinical trials, and is approved in Japan for indications including healing and maintenance of healing of erosive esophagitis, adjunct to antibiotics in H. pylori treatment, gastric ulcer, duodenal ulcer, prevention of recurrence of gastric ulcer or duodenal ulcer during low-dose aspirin or NSAID administration.

Phathom has development and commercialization rights to vonoprazan in the United States, Europe, and Canada, and intends to seek approval in these geographies. We have received qualified infectious disease product (QIDP) designation from the FDA for vonoprazan in combination with certain antibiotics for the treatment of H. pylori infection which provides, among other benefits, potential eligibility for priority review and extension of any regulatory exclusivity awarded if approved.

Phathom Pharmaceuticals is going beyond the expected and working to change the GI treatment landscape for millions of patients suffering from acid-related disorders.

*Vonoprazan is a product candidate that is under clinical study and that has not been approved for marketing by the U.S. Food and Drug Administration. No representation is made as to the safety or effectiveness of vonoprazan.