Discontinuation of Mycobacterium avium Complex Prophylaxis in Patients with Antiretroviral Therapy-Induced Increases in CD4+ Cell Count: A Randomized, Double-blind, Placebo-Controlled Trial [Currier JS, et al. Ann Intern Med 2000;133:493]: This is a randomized, double-blind, placebo-controlled ACTG trial conducted in 29 centers to determine the safety of discontinuing MAC prophylaxis. There were 643 participants with a CD4 cell count <50/mm³ that increased to >100/mm³ for at least one month with HAART. One group continued to receive azithromycin, 1,200 mg weekly, and the second group received placebo. The result at a median follow-up of 16 months showed two cases of MAC infection in the 321 patients assigned to placebo (0.5 events/100 person-years) compared to no cases in the 322 patients given azithromycin. Both cases of MAC were atypical with infection localized to the vertebral spine.
Comment: This study provides support for the revised CDC/IDSA guidelines, which recommend discontinuation of MAC prophylaxis in patients who have CD4 cell counts >100/mm³ [MMWR 1999;48(RR10):1-66]. A curious and unexplained observation was that the time to development of a new or recurrent AIDS-defining condition was significantly longer in those assigned to the azithromycin group. The authors speculated that this difference might be explained by a reduction in immune activation by prevention of mucosal colonization and local invasion of the GI and respiratory tract. posted 10/19/2000