Extensive drug resistant TB still curable: study

BOSTON (Reuters) - Tuberculosis resistant to most drugs can still be cured in 60 percent of cases using aggressive treatment with at least five drugs, doctors reported on Wednesday.

They said their finding offers hope for people with extensively drug-resistant TB or XDR-TB, an infection that is not stopped by two first-line drugs used to treat the disease, along with three of the six classes of second-line drugs.

"It's essential that the world know that XDR-TB is not a death sentence," said Carole Mitnick of Harvard Medical School in Boston, who led the study.

"As or even more importantly, our study shows that effective treatment does not require hospitalization or indefinite confinement of patients," Mitnick said in a statement.

The researchers started with 650 patients in Lima, Peru, who had drug-resistant TB. Of them 48 had XDR-TB and none were infected with the AIDS virus, a complication that makes such TB virtually untreatable.

Doctors offered patients free individualized treatment with at least five drugs given simultaneously, along with surgery to cut out clumps of badly infected tissue and nutritional and psychological support.

Sixty percent were cured by the end of the treatment compared to 66 percent of the 603 volunteers whose TB showed resistance to fewer drugs, Mitnick's team reported in the New England Journal of Medicine.

"Aggressive regimens -- with many drugs, at the highest tolerated doses -- were used to maximize the chemotherapeutic benefit," they wrote.

"Treatment was protracted, lasting more than two years in most patients. The results of drug-susceptibility testing were used to design (and adjust) regimens containing at least five drugs that were likely to be effective whenever possible," they added.

"This encouraging result constitutes a true change in the current perception of the disease as a virtual death sentence," Dr. Mario Raviglione of the World Health Organization wrote in a commentary on the findings.

"The challenge is to make this approach a sustainable reality worldwide."

Raviglione said the study did not report the frequency or seriousness of the side effects, and raised the question of why aggressive treatment programs in the United States and Europe have not been as successful.

"Possibly, the strains causing their disease were resistant to more drugs than the strains in Peru," Raviglione wrote.

A second study of 174 tuberculosis patients treated at National Jewish Health in Denver, a specialty U.S. center, found patients with XDR-TB were almost eight times as likely to die as patients with multi-drug resistant tuberculosis.

Of 174 MDR-TB patients, 10 were classified as XDR-TB. Just 14 of the 164 MDR-TB patients died, compared to half the XDR patients.

"Over the years, we have become quite proficient at treating multi-drug resistant tuberculosis with initial treatment success rates greater than 90 percent in recent years," said Dr. Michael Iseman, who led the study.

"Extensively drug-resistant cases, however, are much more difficult to treat and we still lose more of these patients than we save."

(Editing by Maggie Fox and David Wiessler)