Adding the antibiotic moxifloxacin to the usual TB drugs shortened the time to cure to an estimated four months in a study in Brazil, Johns Hopkins University scientists reported at an American Society for Microbiology conference in Chicago.
A second study by Hopkins researchers cured mice of TB in 10 weeks instead of the usual six months with moxifloxacin plus the TB drug rifapentine at higher doses.
"It sounds fantastic," said Dr. Melvin Spigelman, research and development director for the nonprofit Global Alliance for TB Drug Development in New York. "The science is there" and just needs to be verified in larger studies, he said.
The group will launch a 2,400-patient study later this year.
Also on Tuesday, the Seattle-based Bill & Melinda Gates Foundation announced its largest grants ever to fight TB — $280 million for research on vaccines, diagnostics and drugs.
"If everything goes well, it should be feasible to shorten treatment time," possibly even to ultra-short regimens of two weeks to a month, said Ken Duncan, the foundation's program director.
More than 8 million people worldwide develop TB each year, and nearly 2 million die of it. The disease is mostly a problem in poor countries, but the recent case of Andrew Speaker, an Atlanta attorney who created an international health scare by traveling while he had a multidrug-resistant strain of TB, shows the danger in the United States as well.
Recently, a Mexican teenager was jailed in Georgia and threatened with deportation after refusing to take his recommended nine months of TB treatment.
On Tuesday, a man with a multiple drug-resistant form who had been detained after walking in public without a mask was returned to Arizona after doctors treating him in Colorado said he was no longer infectious.
Treatment now consists of three or four antibiotics taken daily for six months or more. But half of patients do not take all their pills, allowing resistant bacteria to grow and spread, said Dr. Jacques Grosset, the Hopkins researcher who led the study of several hundred mice.
The Brazil study involved about 170 men and women in Rio de Janeiro who had active TB. All were given three standard anti-TB drugs plus either moxifloxacin or an older drug, ethambutol.
After two months, 85 percent of those on moxifloxacin tested negative for the infection compared to 68 percent on ethambutol. The treatment advantage showed up in as little as two weeks.
"Based on what we know, if you get that big a difference at two months, you should be able to shorten the duration of treatment ... down to four," said Dr. Richard Chaisson, director of TB research at Hopkins.
In a third study of about 400 TB patients throughout Africa, 60 percent who received moxifloxacin plus three other drugs tested negative for TB at two months versus 55 percent given isoniazid and the other medications.
The federal government paid for the studies, and Bayer Healthcare AG donated moxifloxacin, which it sells as Avelox in the United States for short-term use against pneumonia and other respiratory illnesses. The pill costs $10 a day, but researchers said Bayer has promised to make it available in poor countries for less if it is approved to treat TB.