Phathom Launches Phase 3 Vonoprazan Trial for GERD

A label expansion pathway for VOQUEZNA (vonoprazan) is now in active execution: Phathom Pharmaceuticals has initiated patient screening in pHalcon-NERD-302, a registrational Phase 3 study evaluating a PRN dosing regimen in adults with Non-Erosive Gastroesophageal Reflux Disease. For regulatory affairs leads, the study design carries direct implications for how a supplemental NDA submission would be structured around an on-demand acid-suppression claim, a regulatory territory where PPIs currently hold no approved U.S. indication.

The trial is a multicenter, randomized, double-blind, placebo-controlled study targeting approximately 500 adults across roughly 80 U.S. sites. Following a four-week open-label run-in with vonoprazan 10 mg once daily, eligible patients are randomized 1:1 to as-needed vonoprazan 10 mg or placebo for 24 weeks. The primary endpoint, assessed at Week 12, measures the percentage of heartburn episodes achieving complete relief within two hours and sustained relief through 24 hours post-dose, a composite efficacy construct that will require robust patient-reported outcome validation in any regulatory submission package.

From a manufacturing and supply planning standpoint, a PRN dosing regimen introduces variable consumption patterns that differ materially from the fixed daily-dose model under which VOQUEZNA's existing commercial supply chain operates. QA and operations teams at contract manufacturers or internal sites supporting the program should anticipate demand forecasting complexity during the 24-week treatment period, particularly given the 1:1 randomization across approximately 80 sites. Batch release schedules and comparator placebo supply will need to accommodate site-level variability in patient dosing frequency.

The study builds on previously reported positive Phase 2 data, which Phathom has cited as the scientific rationale for advancing to a registrational design. Topline results are expected in Q1 2028, at which point the data package would inform a potential label expansion submission. The existing VOQUEZNA approval covers erosive esophagitis treatment and maintenance, as well as H. pylori eradication in combination regimens; a NERD PRN indication would represent a distinct clinical and commercial segment.

If pHalcon-NERD-302 meets its primary endpoint, the Q1 2028 topline readout will mark the earliest point at which Phathom could initiate a supplemental NDA filing strategy for the as-needed indication.

Source: Phathom Pharmaceuticals via GlobeNewswire, September 29, 2026.