Dual therapy with vonoprazan, amoxicillin useful for H. pylori eradication

A 7-day course of vonoprazan and low-dose amoxicillin dual (VA-dual) therapy proves useful in the first-line treatment of Helicobacter pylori infection, especially in regions with high clarithromycin resistance, yielding an acceptable eradication efficacy that is similar to that achieved with vonoprazan-based triple (VAC-triple) therapy, according to the results of an open-label trial.

“Standard triple therapy consisting of a proton pump inhibitor, amoxicillin and clarithromycin is no longer effective in many regions of the world owing to increasing clarithromycin resistance of H. pylori,” the researchers said.

“The VA-dual therapy offers an alternative regimen for H. pylori eradication treatment in the era of increasing antimicrobial resistance… As it is a single antibiotic therapy and antibiotic consumption is low, with no use of clarithromycin, and H. pylori is hardly resistant to amoxicillin, we expect that VA-dual therapy will not contribute to the increase in antimicrobial resistance rates,” they added.

In the trial, 335 treatment-naïve patients (mean age, 61 years; 62.39 percent male) with H. pylori–positive culture test were randomized to receive either VA-dual therapy (vonoprazan 20 mg plus amoxicillin 750 mg twice a day; n=168) or VAC-triple therapy (vonoprazan 20 mg, amoxicillin 750 mg and clarithromycin 200 mg twice a day; n=167) for 7 days.

Eradication success rates, evaluated using 13C-urea breath test at least 4 weeks after treatment, were similar in the VA-dual and VAC-triple arms, 84.5 percent vs 89.2 percent (p=0.203) by intention-to-treat analysis, respectively; and 87.1 percent and 90.2 percent (p=0.372) by per-protocol analysis, respectively. These numbers indicated noninferiority of VA-dual to VAC-triple therapy. [Gut 2020;doi:10.1136/gutjnl-2019-319954]

Of note, VA-dual therapy produced a significantly higher eradication rate in strains resistant to clarithromycin compared with VAC-triple (92.3 percent vs 76.2 percent; p=0.048).

The incidence of adverse events (AEs) did not significantly differ between the two treatment arms, 27.4 percent with VA-dual and 30.5 percent with VAC-triple (p=0.524). Most events were mild-to-moderate in severity, and all resolved spontaneously without intervention, except for skin rash. None of the patients were hospitalized due to AEs.

“The results of this study suggest that VA-dual therapy can be used as first-line H. pylori empirical treatment, and that susceptibility-based therapies using multiple antibiotic agents should be used as rescue therapy only in cases where the VA-dual therapy fails,” the researchers pointed out.

There are merits to using VA-dual therapy, they continued. For the most part, it makes use of a single antibiotic in low dose. This said, the strategy should hence “limit unnecessary antibiotic usage, prevent widespread resistance development of other organisms, and reduce the costs of H. pylori treatment,” they explained.

Nevertheless, there is the potential to improve the eradication effect of VA-dual therapy through adjustments in the administration of amoxicillin, the researchers added.

“Thus, further studies should be demanded to develop VA-dual therapy with proper adjustments and to establish new first-line H. pylori eradication treatments in the era of growing antimicrobial resistance,” they said.