As described in the July 7, 2011 New England Journal of Medicine
, Richard Chaisson
from Johns Hopkins University's
Center for Tuberculosis Research tested 4 TB prophylaxis regimens in more than 1000 HIV positive people in South Africa who were not on ART.
"This new, simpler treatment regimen with rifapentine and isoniazid is highly effective and could transform therapy for latent tuberculosis in both those co-infected with HIV and those not," says study senior author Richard Chaisson, MD, a professor of infectious diseases at the Johns Hopkins University School of Medicine and founding director of its Center for Tuberculosis Research.
"New treatment options are urgently needed to help control TB globally, and simpler regimens will substantially increase the number of people receiving therapy," says Chaisson
, who points out that fewer than 1 percent of those infected and most likely to develop full-blown TB are receiving drug treatment because of inconvenience, drug side effects and difficulty finding health clinics close to where they live.
says the latest study in 1,148 South African men and women co-infected with HIV, and another recent study, in which he
was also involved, in more than 8,000 men and women in the United States, Canada, Spain and Brazil who mostly were HIV free, show success for the first new treatment option since rifapentine, marketed as the drug Priftin, was approved for use in the United States in 1998.
adds that the results represent the most significant advance in preventing the disease since isoniazid was first proven effective in treating the disease in the 1950s.
TB is the leading cause of death among people co-infected with HIV, the virus that causes AIDS, leading to some half-million deaths annually among those co-infected.
says the streamlined, weekly regimen is much easier for patients to follow, with 95 percent having completed treatment in this study, while traditional daily and longer isoniazid therapy shows a compliance rate of about 60 percent or less in other studies and in practice.
This is important, he
notes, because isoniazid does not work if treatment is interrupted and people stop taking it as prescribed.
Such obstacles in treatment, as well as fears about producing drug-resistant bacteria, in addition to drug toxicity and liver damage in people who also have HIV, probably explain why the vast majority of physicians in South Africa do not prescribe isoniazid treatment alone to prevent TB, Chaisson
says, even though it is therapy recommended by the World Health Organization
Observed side effects were mild, Chaisson
says, with some liver damage occurring in 20 percent of study participants taking isoniazid for the longer term, and in about 5 percent of those using alternative regimens.
However, the key problem with both rifamycin-based medications, Chaisson
acknowledges, is that they break down in the liver other drugs, such as protease inhibitors, widely used to fight HIV.
international colleagues next plan to gauge the effectiveness of even shorter regimens, such as high doses of rifapentine and isoniazid daily, but only for one month.
says the aim of his
research is to "open up" access to drug therapies for everyone with TB, as a means of better controlling the disease.