Phathom Pharmaceuticals Submits Vonoprazan NDA to FDA for the Treatment of Erosive Esophagitis

Phathom Pharmaceuticals, Inc. recently announced it has submitted a new drug application (NDA) to the US FDA for the use of vonoprazan as a treatment for adults for the healing of all grades of erosive esophagitis (EE) and relief of heartburn, and maintenance of healing of all grades of EE and relief of heartburn.

Erosive esophagitis, a major type of gastroesophageal reflux disease (GERD), affects approximately 20 million people in the US. In addition to experiencing troubling heartburn symptoms, patients with inadequately treated EE may progress to more severe diseases including Barrett’s esophagus, a condition in which esophageal tissue changes can progress to cancer.

“The submission of this NDA is another exciting step towards bringing the first major innovation to the U.S. GERD market in over 30 years,” said Azmi Nabulsi, MD, Chief Operating Officer at Phathom. “Proton pump inhibitors (PPIs) are currently the standard of care for EE yet approximately half of all US patients progress their lines of therapy annually. We believe there is great interest among patients and healthcare providers for new treatment options to address the shortcomings of current treatment. If approved, vonoprazan has the potential to satisfy the large unmet needs of millions of patients and set a new treatment paradigm in EE.”

This NDA is based on the positive data previously announced from Phathom’s pivotal Phase 3 PHALCON-EE trial, a randomized, double-blind, multicenter trial that enrolled 1,024 patients with EE in the US and Europe and compared vonoprazan to lansoprazole, a standard of care PPI, in the healing and maintenance of healing of EE, and heartburn symptom relief. PHALCON-EE successfully met its primary endpoints and key secondary superiority endpoints.

Erosive esophagitis is a condition characterized by the presence of breaks, or erosions, in the esophageal tissue caused by constant irritation of the mucosal surface and subsequent loss of defense mechanisms against acid and digestive enzymes. Chronic erosive esophagitis can lead to complications including peptic stricture, a narrowing of the esophagus that causes difficulty swallowing, and Barrett’s esophagus, a condition in which esophageal tissue changes can progress to cancer. Uncontrolled reflux disease can also result in extra-esophageal diseases such as respiratory problems, chest pain, angina, and increased mortality.

PHALCON-EE was a randomized, double-blind, two-phase, multicenter, Phase 3 trial that enrolled 1,024 patients with EE in the US and Europe. The first phase of the trial evaluated the efficacy and safety of vonoprazan 20 mg administered once-daily (QD) compared to lansoprazole 30 mg QD for the healing of EE for up to 8 weeks. The second phase of the trial evaluated the efficacy and safety of vonoprazan 10 mg QD and 20 mg QD compared to lansoprazole 15 mg QD for the maintenance of healing of EE for 24 weeks. Both phases also evaluated heartburn symptoms.

Vonoprazan is an investigational, oral small molecule potassium-competitive acid blocker (P-CAB). P-CABs are a novel class of medicines that block acid secretion in the stomach. Vonoprazan has shown the potential to have rapid, potent, and durable anti-secretory effects as a single agent in the treatment of gastroesophageal reflux disease (GERD) and in combination with antibiotics for the treatment of Helicobacter pylori (H. pylori) infection. The FDA has awarded qualified infection disease product (QIDP) status and granted Fast Track designation to vonoprazan in combination with both amoxicillin and clarithromycin and with amoxicillin alone for the treatment of H. pylori infection. Phathom in-licensed the US, European, and Canadian rights to vonoprazan from Takeda, which completed 19 Phase 3 trials for vonoprazan and received marketing approval in Japan and numerous other countries in Asia and Latin America.

Phathom Pharmaceuticals is a biopharmaceutical company focused on the development and commercialization of novel treatments for gastrointestinal diseases and disorders. Phathom has in-licensed the exclusive rights in the United States, Europe, and Canada to vonoprazan, a novel potassium competitive acid blocker (P-CAB) in late-stage development for the treatment of acid-related disorders. For more information, visit www.phathompharma.com.