New antibiotic drug combo to speed up treatment of tuberculosis

A team of tuberculosis (TB) experts at Johns Hopkins and in Brazil have evidence that substituting the antibiotic moxifloxacin in the regimen of drugs used to treat the highly contagious form of lung disease could dramatically shorten the time needed to cure the illness from six months to four.

Adding moxifloxacin to a standard combination of other antibiotics increased by 17 percent the number of patients who cleared active infections from their lungs (raising cure rates from 68 percent to 85 percent), after just two months of therapy, and when compared to patients taking the standard combination with another, older antibiotic, ethambutol.

“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, M.D., 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. Chaisson will present his team’s findings Sept. 18 in Chicago at the 47th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC).

“Beyond the obvious value of healing patients more quickly, a shorter treatment time could also cut down on transmission of the disease to others and make it easier for health care workers worldwide, who are overwhelmed by large numbers of patients, to treat more people and to treat them faster,” says Chaisson, who started the study in 2003.

He notes that worldwide, each year, nearly 9 million new cases of TB are diagnosed, and more than one and a half million people die from the disease, caused by Mycobacterium tuberculosis.

TB also remains the leading cause of death worldwide among those with HIV and AIDS and is epidemic in developing countries with the highest HIV-infection rates.

The new study of more than 170 men and women in Rio de Janeiro, Brazil – all with active TB – showed that combination drug therapy with moxifloxacin was more potent than combination therapy with an older, more traditional anti-TB drug, ethambutol. Symptoms of active TB include fever, cough, night sweats and weight loss.

After two months of combination therapy, cultured sputum samples from patients taking moxifloxacin were significantly less likely to grow TB bacteria than samples from those on traditional ethambutol therapy. The time to clear the infectious organism from sputum was also significantly shorter in the moxifloxacin group.

Conventional TB therapy prescribes a mix of antibiotics, typically four, given in view of a caregiver and taken together for six months. Commonly known by its acronym DOTS, short for Directly Observed Therapy Short-Course, the treatment cures on average 95 percent of patients who finish taking their medications as originally prescribed.