Adding the antibiotic moxifloxacin to the drug regimen used to treat tuberculosis (TB) could dramatically shorten the time needed to cure the illness, reported researchers in a presentation at the 47th Interscience Conference on Antimicrobial Agents and Chemotherapy on Sept. 18.
A research team at Johns Hopkins University School of Medicine, Baltimore, conducted a study involving more than 170 men and women in Rio de Janeiro, Brazil, who all had active TB. All participants were given a standard combination of three antibiotic drugs—isoniazid, rifampin and pyrazinamide—and then were randomly assigned to receive a fourth antibiotic drug—moxifloxacin or ethambutol. Moxifloxacin, approved for use in the United States since 1999 as a treatment for pneumonia, is not approved as a treatment for TB. Ethambutol has been approved to treat TB since 1962.
After subjects received two months of combination therapy, researchers found that cultured sputum samples from patients in the moxifloxacin combination group were significantly less likely to grow TB bacteria than were samples from subjects in the ethambutol combination group. They also found that the time to clear the infectious organism from sputum was significantly shorter in those in the moxifloxacin group than in the ethambotol group.
"This is the most compelling evidence in nearly 25 years that a novel antibiotic drug combination works better than the current gold standard at curing active TB infection," says study senior author Richard E. Chaisson, MD, a professor of medicine, epidemiology and international health at the Johns Hopkins University School of Medicine and founding director of its Center for Tuberculosis Research.
The research team plans to investigate a standard drug combination that includes rifapentine instead of rifampin. Rifapentine became available in the United States in 1998, and scientists say it is more effective against drug-resistant strains of TB.
The U.S. Food and Drug Administration’s Office of Orphan Product Development provided funding for the research. Bayer donated supplies of moxifloxacin.
