The three combination drugs, which must be taken several times daily for six to eight months, have all been widely used to treat TB disease for decades: isoniazid (since 1952), rifampin (1968) and pyrazinamide (1954).
It was remarkable to see just how potent moxifloxacin was, says Chaisson. After just two weeks of therapy with moxifloxacin, 21 percent of the sputum samples were negative and cleared of visible disease, while in the ethambutol study group, it was just 3 percent. After four weeks, the gap widened to 51 percent and 29 percent, respectively.
Chaisson says substituting moxifloxacin for one of the key ingredients in DOTS could also make treatment far less costly overall, allowing TB programs to expand their coverage. The medication currently costs $10 per day for short-term use, but the researcher says the drugs manufacturer, Bayer Healthcare AG, has promised to make the drug available at affordable prices in poor countries should it gain approval for use in TB.
Chaisson and his team next plan to investigate a potentially even more potent drug combination that includes traditional DOTS drugs with yet another substitution, rifapentine in place of rifampin. Rifapentine became available in the United States in 1998 and scientists say it is more effective against drug-resistant strains of TB.
Chaisson and colleagues conducted their research with funding from the U.S. Food and Drug Administrations Office of Orphan Product Development. The study was part of a series of studies on moxifloxacin that are being coordinated by the nonprofit Global Alliance for TB Drug Development (GATB) in collaboration with Bayer.
The GATB estimates that 1 billion people worldwide will be infected with tuberculosis by the year 2020, of whom 200 million will fall ill and 35 million will die.
As part of the research program, Bayer donated supplies of moxiflo
|Contact: David March|
Johns Hopkins Medical Institutions