A three-drug combo that includes an experimental treatment from the Global Alliance for TB Drug Development may cure tuberculosis more quickly than current regimens, a study found, offering new hope to patients with HIV.
At least one-third of 35 million people with HIV worldwide have latent TB, and they’re 30 times more likely to develop the active disease. The majority of dual infections are in Africa, where TB is the top cause of death among the HIV-positive, according to the World Health Organization. About one in five with HIV die of the lung infection worldwide.
In a two-month trial, 71 percent of TB patients were cleared of the bacteria, making it twice as effective as the standard treatment, according to a study presented this week at the International AIDS Conference in Melbourne, Australia.
“Getting a better handle on treating patients, especially shutting off the production of drug resistance and curing drug resistance more quickly is just a really pivotal step in eradicating TB,” said Mel Spigelman, president of the New York-based TB Alliance that developed the treatment.
Co-infections of HIV and other viruses, including hepatitis C and TB, have received specific attention at this year’s AIDS conference, with research presented into new drugs that don’t have dangerous interactions with HIV-targeted therapies.
About 20 percent of patients enrolled in the TB study had HIV and showed the same level of success as non-HIV patients, Spigelman said.
Current treatments for drug-resistant TB involve daily injections, sometimes for as long as six months, and can last as long as two years. The logistical challenge of the current long-term treatments for TB keep many from completing the full course, said Amrita Daftary, a postdoctoral fellow with ICAP, formerly the International Center for AIDS Care and Treatment Programs at Columbia University in New York.
“If you’re suddenly cutting down that regimen to 6 months you’re probably going to see more people completing the treatment,” Daftary said by telephone. “It would be such a boon because it would reduce the stigma associated with TB.”
Unlike existing treatments, the drug combination, dubbed PaMZ, is designed to be used for both drug-resistant and drug-sensitive tuberculosis, the researchers said.
The combo’s components include: PA-824, a drug licensed by the TB Alliance from Chiron in 2002; moxifloxacin, an antibiotic developed by Bayer AG that hasn’t been approved previously for TB treatment; and pyrazinamide, an existing drug used in current therapies. All are taken orally.
While only nine patients with drug-resistant TB were included in TB Alliance trial, there’s evidence it is effective in that population from previous two-week studies and animal data, Spigelman said.
The next step is to secure enough funding for final testing of the combination treatment in a Phase 3 trial, Spigelman said. The study will enroll about 1,500 patients and include more with drug-resistant TB.
“The big challenge in getting new treatments for TB is the lack of funding,” he said. “The money that’s gone into new drugs has been dropping over time.”
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