Phathom announced the FDA approval of vonoprazan tablets, amoxicillin capsules, clarithromycin tablets (Voquezna Triple PAK, Phathom) and vonoprazan tablets, amoxicillin capsules (Voquezna Dual PAK, Phathom) for treatment of Helicobacter pylori infection in adults.
The approval of vonoprazan—a potassium-competitive acid blocker (PCAB)—marks the first time in 30 years that a novel acid suppressant from a new drug class has been approved. Both treatment regimens come in blister packs to improve patient compliance.
PCABs block acid secretion in the stomach, and vonoprazan has been observed to provide sufficient acid suppression to achieve pH levels crucial to increase the effectiveness of the antibiotics co-packaged with it.
The safety and efficacy of both regimens were based on results of the phase 3 PHALCON-HP trial, the largest H. pylori-based registrational trial in the United States, with over 1,000 randomized patients. The two treatments showed, in the modified intent-to-treat population, noninferiority to lansoprazole-based triple therapy in patients who did not have the clarithromycin- or amoxicillin-resistant strain of H. pylori at baseline. The triple-agent regimen had an observed H. pylori eradication rate of 84.7%, compared with 78.8% for lansoprazole-based triple therapy (95% CI, -0.8 to 12.6). The dual treatment regimen had an eradication rate of 78.5%, compared with 78.8% for lansoprazole-based triple therapy (95% CI, -7.4 to 6.8).
For the total trial population, including patients with clarithromycin-resistant strains of H. pylori, both treatments outperformed lansoprazole combined with amoxicillin and clarithromycin in the eradication of the H. pylori infection. The vonoprazan-based triple therapy resulted in an 80.8% eradication rate compared with 68.5% for lansoprazole-based triple therapy (95% CI, 5.7- 18.8). The eradication rate for the total population for vonoprazan-based dual therapy was 77.2%, compared with 68.5% for lansoprazole-based triple therapy (95% CI, 1.9-15.4).
Rates of adverse events for the vonoprazan combination treatments were similar to those observed with lansoprazole-based triple therapy. The most common adverse events reported for vonoprazan-based triple therapy, vonoprazan-based dual therapy and lansoprazole-based triple therapy in the trial, respectively, were diarrhea (4.0%, 5.2%, 9.6%), dysgeusia (4.6%, 0.6%, 6.1%), vulvovaginal candidiasis (3.2%, 2.0%, 1.4%), abdominal pain (2.3%, 2.6%, 2.9%), headache (2.6%, 1.4%, 1.4%), hypertension (2.0%, 1.1%, 0.9%) and nasopharyngitis (0.3%, 2.0%, 0.9%).
—GEN Staff