Phathom Pharmaceuticals' erosive esophagitis treatment approved by FDA

02-Nov-2023 - Last updated on 02-Nov-2023 at 11:26 GMT

The US Food and Drug Administration (FDA) has approved a potassium-competitive acid blocker (PCAB) as a new treatment for the healing of all grades of erosive esophagitis.

Phathom Pharmaceuticals Inc. made the announcement yesterday (November 1) that the condition also known as erosive GERD (gastroesophageal reflux disease) responds to Voquenza (vonoprazan) tablets 10mg and 20mg for the maintenance healing of all grades of erosive GERD, and relief of heartburn associated with the condition.

Based on the terms of Phathom’s revenue interest financing agreement, the FDA approval of Voquenza for Erosive GERD also entitles the company to receive a $175 million payment. This non-dilutive capital will help fund the commercial launch.

“This approval demonstrates Phathom's commitment to changing the GI treatment landscape for patients and healthcare providers, bringing the first major innovation to the U.S. Erosive GERD market in over 30 years,” said Terrie Curran, president, and chief executive officer at Phathom.

“Erosive GERD can be extremely painful and often has a significant impact on patients. Research has shown patients and healthcare providers are largely unsatisfied with current treatments and we are excited about the approval of a first-in-class treatment option that has the potential to meet a large unmet medical need.”

Erosive acid reflux

Phathom says erosive GERD, also referred to as erosive esophagitis or erosive acid reflux, is a major type of GERD that affects approximately 20 million people in the US. In addition to experiencing troubling heartburn symptoms, patients with inadequately treated erosive GERD may develop more severe diseases including Barrett’s esophagus, a condition in which oesophageal tissue changes can progress to cancer.

This approval is based on positive results from the Phase 3 PHALCON-EE study. The pivotal trial was a randomized, double-blind, multicenter study that enrolled 1,024 patients with erosive GERD in the US and Europe and compared Voquenza to the PPI lansoprazole in the healing and maintenance of healing of Erosive GERD and associated heartburn symptom relief.

Results showed that Voquenza 20 mg met the primary endpoint of non-inferiority for complete healing by week 8 in patients with all grades of Erosive GERD with a healing rate of 93% compared to 85% for lansoprazole 30 mg, with superior rates of healing demonstrated in a secondary endpoint in patients with the moderate-to-severe disease (LA Grade C/D) at week 2 compared to lansoprazole (70% for Voquenza 20 mg and 53% for lansoprazole 30 mg). Voquenza 20 mg also demonstrated non-inferiority to lansoprazole 30 mg in the mean percentage of 24-hour heartburn-free days over the healing period.

In the maintenance phase of the trial, Voquenza 10mg was superior to lansoprazole 15 mg in maintaining healing at six months in all randomized patients (79% for Voquenza 10 mg, compared to 72% for lansoprazole 15mg) as well as in the subset of patients with moderate-to-severe erosive GERD (75% for Voquenza 10mg, compared to 61% for lansoprazole 15mg). In addition, Voquenza 10mg was evaluated as a secondary endpoint for relief of heartburn in erosive GERD patients and demonstrated non-inferiority to lansoprazole 15mg over six months.

Adverse effects comparable to lansoprazole

Adverse event (AE) rates for Voquenza were comparable to lansoprazole in the trial. The most common AEs in the healing phase were gastritis, diarrhea, abdominal distension, abdominal pain, and nausea.

“For many GERD patients with Erosive Esophagitis, the response to current treatment is suboptimal, leaving them with incomplete healing and ongoing symptoms,” said Colin Howden, professor emeritus, University of Tennessee College of Medicine.

“The FDA approval of Voquenza provides healthcare providers with a new first-in-class therapeutic option that demonstrated faster healing in the more difficult-to-treat GERD patients with Erosive Esophagitis. In addition, Voquenza provided superior maintenance of healing in all grades of Erosive Esophagitis, compared to lansoprazole, a commonly prescribed PPI, and provided 24-hour heartburn relief on most days in the trial.”

The treatment is expected to be available in the US in December 2023 and will be marketed exclusively by Phathom Pharmaceuticals, Inc.