FDA Approves Rifamycin for Traveler's Diarrhea

The US Food and Drug Administration (FDA) has approved rifamycin (Aemcolo), an antibacterial therapy indicated for the treatment of noninvasive Escherichia coli (E. coli)-driven traveler’s diarrhea in adult patients.

The approval, which is indicated for cases wherein the patient is not complicated by fever or blood in their stool, was based on the efficacy and safety results across 3 clinical trials.

In a randomized, placebo-controlled clinical trial involving 264 adults with traveler’s diarrhea in Guatemala and Mexico, rifamycin significantly reduced symptoms versus placebo. In 2 controlled clinical trials, orally-administered rifamycin, taken over 3-4 days, was evaluated in 619 adults with traveler’s diarrhea. The most common adverse reactions in patients were headache and constipation.

In patients with diarrhea complication by fever and/or bloody stool, or diarrhea due to pathogens other than noninvasive strains of E. coli, rifamycin was shown to be ineffective and is therefore not recommended for use in such patients.

The FDA had previously granted rifamycin was Qualified Infectious Disease Product (QIDP) designation, indicating its role as a therapy for serious or life-threatening infections under the Generating Antibiotic Incentives Now title of the FDA Safety and Innovation Act. Under the QIDP designation, the therapy’s marketing application granted Priority Review.

As the most common travel-related sickness—affecting about 10% to 40% of travelers worldwide annually—traveler’s diarrhea is defined by 3-plus unformed stools within 24 hours. Its prevalence in Asia, Middle East, Africa, Mexico, Central and South America, as well as its basis in bacteria found in food and water, makes it a pivotal condition to treat.

"Travelers' diarrhea affects millions of people each year and having treatment options for this condition can help reduce symptoms of the condition," said Edward Cox, MD, MPH, director of the Office of Antimicrobial Products in the FDA’s Center for Drug Evaluation and Research.