Phathom Pharma Resubmits Vonoprazan NDA

FDA has accepted for review a Phathom Pharmaceuticals NDA resubmission for vonoprazan, a first-in-class potassium-competitive acid blocker to treat erosive gastroesophageal reflux disease (erosive esophagitis). The company says the resubmission responds to an agency 2/2023 complete response letter relating to specifications and controls for a nitrosamine drug substance-related impurity. Phathom says it implemented mitigation measures, including a minor drug product tablet reformulation to inhibit the growth of the impurity, and has been conducting a stability program to demonstrate the measures are effective and support the commercial shelf life.

The resubmitted NDA contains three months of stability data for six batches of the reformulated vonoprazan tablets, Phathom says, adding that it will continue to provide additional stability data during the regulatory review as previously agreed with FDA. The agency has set an 11/17 user fee review action target date.