The FDA requested additional data showing the levels of a nitrosam impurity was below the set threshold throughout the life of vonoprazan.
The US Food and Drug Administration (FDA) has opted not to take action on a New Drug Application for vonoprazan, a potassium-competitive acid blocker, under review to treat patients with erosive esophagitis.
The agency previously set a Prescription Drug User Fee Act (PDUFA) target action date of January 11, 2023 for the drug, developed by Phathom Pharmaceuticals.
The application was derailed after the company announced on August 2, they had detected trace levels of N-nitroso-vonoprazan, a nitrosamine impurity, in commercial batches. At the time they said they were working closely with the agency to obtain approvals on a proposed acceptable daily intake limit, test method, and controls to address the issue.
The FDA has established an acceptable daily intake limit of 96 ng per day but has since requested additional stability data showing the levels of NVP remain below that limit throughout the proposed shelf life of the drug.
“While we are disappointed not to launch vonoprazan later this quarter, we are otherwise very pleased with the NDA review progress, including ongoing label negotiations which we are optimistic will conclude shortly,” said Terrie Curran, President and Chief Executive Officer of Phathom, in a statement. “We are confident in our ability to meet the nitrosamine limit and expect to update anticipated launch timing after gaining further clarity on the stability requirements from the FDA. Meanwhile, we are maintaining our launch-readiness position and remain excited about vonoprazan’s commercial potential as the first major innovation in the U.S. erosive GERD market in over 30 years.”