Prophylactic treatment for the opportunistic infection known as MAC (Mycobacterium avium complex) can be safely discontinued in most HIV-infected patients whose CD4+ T-cell levels show sustained increases in response to potent antiretroviral therapy, according to interim results of a study supported by the National Institute of Allergy and Infectious Diseases (NIAID). Study Chair Judith Currier, M.D., associate professor of medicine at the University of California, Los Angeles, will present the findings on Monday, Sept. 27, during a late-breaker session at the 39th Interscience Conference on Antimicrobial Agents and Chemotherapy being held in San Francisco.
Before highly active antiretroviral therapy (HAART) became available in the mid-1990s, MAC was one of the most common serious opportunistic infections associated with HIV infection. It usually caused widespread infection in multiple organs, leading to debilitating symptoms and significantly decreased chances of survival.
Nearly two years ago, the AIDS Clinical Trials Group (ACTG), a network of HIV research clinicians supported by NIAID, launched a multicenter study known as ACTG 362. The purpose of the study was to determine if an adequate response to HAART--defined as a sustained rise in CD4+ T cells from less than 50 to more than 100 per cubic millimeter (mm3) of blood--protected HIV-infected individuals from developing MAC infection.
A total of 643 patients enrolled in the two-arm, placebo-controlled study. By random assignment, 321 received placebo and 322 received once-weekly, 1200-milligram (mg) doses of azithromycin, supplied by the drug manufacturer, Pfizer. Azithromycin is one of the standard drug regimens given patients to prevent MAC. Patients whose CD4+ T-cell counts later fell below 50 were switched to open-label azithromycin.
An interim analysis of the data accrued through the end of July 1999 showed that
after a median follow-up of 56 weeks, there were no signif
Contact: Laurie K. Doepel
NIH/National Institute of Allergy and Infectious Diseases