SAN ANTONIO – David Y. Graham, MD, asserted at the annual meeting of the American College of Gastroenterology.
The drug, recently approved as Talicia, is a rifabutin-based triple therapy. Each capsule contains 50 mg of rifabutin, 1,000 mg of amoxicillin, and 40 mg of omeprazole. As in the pivotal phase 3 trial led by Dr. Graham, the approved treatment regimen calls for adults to take four capsules every 8 hours for 14 days.
The impetus for developing the new therapy centers on the growing problem of resistance to long-standard agents for H. pylori eradication, including metronidazole and clarithromycin. The World Health Organization has declared H. pylori eradication to be a high priority for therapeutic development. Rifabutin resistance is rare: In one study, 413 of 414 strains of H. pylori were sensitive to the antibiotic, noted Dr. Graham, professor of medicine at Baylor College of Medicine, Houston.
He presented the results of the pivotal phase 3, double-blind, multicenter, active comparator trial, known as ERADICATE Hp2, in which 455 participants with confirmed H. pylori infection were randomized to a course of the all-in-one-capsule triple drug combo or to dual therapy with four capsules, each containing 1,000 mg of amoxicillin and 40 mg of omeprazole, every 8 hours for 14 days.
The primary endpoint was H. pylori eradication as documented by a negative urea breath test obtained 4-6 weeks after completing 14 days of treatment. The rate was 84% with the rifabutin-based combo, compared with 58% seen with the high-dose dual therapy. Moreover, in a prespecified secondary analysis restricted to the 391 participants who were confirmed to be actually taking their medication as evidenced by a positive blood level measured on day 13, the eradication rates rose to 90% and 65%, respectively.
The antimicrobial resistance rates documented in this study were eye opening: 17% of patients’ strains were resistant to clarithromycin, 44% to metronidazole, and 10.5% to both. Of concern, 6.4% of participants’ strains were amoxicillin resistant.
“For the first time we saw a low level – but a definite level – of amoxicillin resistance. That’s something we had not seen previously,” Dr. Graham said.
No rifabutin resistance was detected before or after treatment.
The side effect profiles of the two treatment regimens were similar. Diarrhea was reported by 9% of participants, headache by 7%, and nausea by 5%. No serious adverse events occurred in the 14-day study.
The efficacy of the rifabutin-based therapy wasn’t affected by metronidazole or clarithromycin resistance.
The ERADICATE Hp2 trial was sponsored by RedHill Biopharma of Tel Aviv. Dr. Graham reported having no financial conflicts.