By Laurie Fickman
Omadacycline (Nuzyra, Paratek) may help prevent Clostridioides difficile infections, which are responsible for nearly 500,000 infections annually in the United States (J Infect Dis 2023 Dec 5. doi:10.1093/infdis/jiad537).
Omadacycline had demonstrated a low likelihood of causing C. difficile in clinical trials, but no one understood why. In a small phase 1 human clinical trial, Kevin Garey, PharmD, MS, the Robert L. Boblitt Endowed Professor of Drug Discovery at the University of Houston College of Pharmacy, assessed the pharmacokinetics and gut microbiome effects of oral omadacycline compared with vancomycin.
Although vancomycin is used to treat C. difficile, it is not good at eliminating it over the long term.
Dr. Garey’s team investigated whether omadacycline, given orally, achieves high concentrations in the gut and its effects on the gut microbiome. Sixteen healthy volunteers tolerated omadacycline with no safety differences compared with vancomycin.
A rapid initial increase in fecal concentration of omadacycline was observed compared with vancomycin, with maximum concentrations achieved within 48 hours. Rapid increase is a good thing—it means the active drug is getting to the site of the infection faster, according to Dr. Garey.
“Both the omadacycline and vancomycin groups showed significant changes in their microbiomes when we looked at how diverse they were internally (alpha diversity). However, when we compared the changes between the two groups (beta diversity), they were noticeably different from each other,” Dr. Garey explained.
“Omadacycline caused a distinctly different effect on the microbiome than vancomycin. This could explain why omadacycline is a safe drug to give to patients at high risk for C. difficile infection. This could become a new method in drug development to see if antibiotics are not only killing the bacteria causing infections (the bad bugs) but not causing harm to the beneficial microbes that live in our body (the good bugs),” Dr. Garey said.
Omadacycline is indicated for the treatment of adults with community-acquired bacterial pneumonia and acute bacterial skin and skin structure infections caused by selected susceptible microorganisms.
The original story appeared on the University of Houston website and was edited for style.
