RedHill Biopharma’s lead asset, antibiotic cocktail RHB-105, bested an amoxicillin combination in patients with H. pylori infection, topline phase 3 data show. The results set RedHill up for an FDA filing in the first half of 2019 and, assuming all goes well, a launch by the end of the year.
RHB-105 is a combination of the antibiotics rifabutin and amoxicillin, and omeprazole, a proton pump inhibitor used to treat conditions in which there is too much acid in the stomach. The ERADICATE Hp2 study is a two-arm, randomized, double-blind, active comparator-controlled, confirmatory study involving 455 patients with dyspepsia—or indigestion—who also had H. pylori infection. Patients were randomized to receive four capsules three times a day for 14 days of either RHB-105 or of the active comparator, a combination of amoxicillin and omeprazole.
RHB-105, which RedHill plans to market as Talicia, met its primary endpoint, logging an 84% reduction in H. pylori infection, compared to the 58% achieved by the comparator treatment. Current treatments are about 60% effective, according to The Toronto Consensus for the Treatment of Helicobacter pylori Infection in Adults, published in 2016. But RedHill says their efficacy will only keep declining because H. pylori is highly resistant to antibiotics.
The investigators took H. pylori cultures from patients in 20 U.S. states, finding high resistance to two antibiotics commonly used to treat this infection: 17% resistance to clarithromycin and 43% resistance to metronidazole.
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“The growing resistance of H. pylori to the antibiotics commonly used in standard-of-care therapies was confirmed in this study, which demonstrated the high resistance of the Helicobacter bacteria to clarithromycin and metronidazole,” said David Graham, M.D., M.A.C.G., a professor of gastroenterology at Baylor College of Medicine and lead investigator of the ERADICATE Hp2 study. “The resulting high failure rates of standard-of-care treatments, estimated at 30-40%, are a major public concern among the medical community worldwide and underscore the urgent need for new H. pylori eradication therapies, especially those utilizing antibiotics where resistance is rare such as amoxicillin and rifabutin.”
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If approved, RHB-105 will be the first internally developed drug that RedHill brings to market. The company has an antibiotic cocktail for Crohn's disease in phase 3, as well as a handful of assets targeting other GI indications. It currently has the U.S. promotion rights to Donnatal, Concordia Pharmaceuticals’ treatment for irritable bowel syndrome and acute enterocolitis, as well as to Mytesi, Napo Pharmaceuticals’ antidiarrheal drug for HIV/AIDS patients on antiretroviral therapy. The company also markets ParaPRO’s esomeprazole strontium delayed-release capsules in certain U.S. territories.