We are driven to wake up a dormant therapeutic area and usher in a new era of treatment for patients with acid-related disorders


Phathom Pharmaceuticals is working to change the GI treatment landscape and improve the lives of patients with acid-related disorders. Phathom is developing vonoprazan, a potassium-competitive acid blocker (P-CAB). Vonoprazan has the potential to be the first gastric, anti-secretory agent from a new class approved in the United States, Europe, or Canada in over 30 years. We are currently running clinical trials in erosive gastroesophageal disease and H. pylori infection, and evaluating the development of vonoprazan for other acid-related disorders.*

Introducing our investigational candidate, vonoprazan, a P-CAB with a differentiated mechanism of action and pharmacologic profile.


  • 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.

Current limitations in GERD and H. pylori infection

Gastric acid is secreted by the hydrogen potassium ATPase (also known as the proton pump). While proton pump inhibitors (PPIs) are the current standard of care for acid-related diseases, they have limitations that result in a large, unmet medical need.

In GERD, PPI therapy is suboptimal for many patients due to the slow onset and insufficient duration of acid control, which can lead to inadequate symptom relief. Approximately 15% to 45% of GERD patients remain inadequately treated with PPIs.

In the treatment of H. pylori  infection, the standard of care consists of a combination of a PPI and at least two oral antibiotics. However, increasing antibiotic resistance has resulted in declining eradication rates with PPI-based therapy.

We believe these unmet medical needs are in part driven by limitations associated with the mechanism of action and pharmacokinetics of PPIs.

*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.