A recent study by El-Sadr and colleagues4 provides useful data that should be beneficial to physicians caring for HIV-infected persons and to persons who formulate the U.S. Public Health Service/Infectious Diseases Society of America (USPHS/IDSA) guidelines.3 Current guidelines state that “although the optimal criteria for discontinuing Mycobacterium avium (MAC) complex prophylaxis remain to be defined, a reasonable option would be to consider discontinuing MAC prophylaxis in patients with CD4+ T-lymphocyte count greater than 100 cells per mL (100 X 106 per L) for a sustained period (e.g., three to six months) and suppression of HIV plasma RNA for a similar period.4
El-Sadr and colleagues4 investigated the question of whether MAC prophylaxis can be safely discontinued in patients whose CD4+ cell counts have substantially increased with highly active antiretroviral therapy. They conducted a multicenter, double-blind, randomized trial of azithromycin treatment versus placebo in HIV-infected patients whose CD4+ cell counts had increased from less than 50 per mL (50 X 106 per L) to greater than 100 per mL with highly active antiretroviral therapy. The primary end point was MAC disease or bacterial pneumonia.
During a median of 12 months of follow-up, they found no episodes of confirmed MAC disease in either group. In addition, the number of patients with bacterial pneumonia did not differ significantly between treated patients and patients who received placebo (three patients in the azithromycin group [1.2 percent] versus five in the placebo group [1.9 percent]). Neither HIV nor the mortality rate differed significantly between the two groups. Based on these findings, the authors concluded that azithromycin prophylaxis can safely be withheld in HIV-infected patients with CD4+ cell counts greater than 100 per mL in response to highly active antiretroviral therapy.
The study by El-Sadr and colleagues4 did not specifically state the duration of time that their patients CD4+ titers and HIV-RNA loads were monitored prior to study randomization (their article mentions . . . count of more than 100 cells per mL on two consecutive occasions . . .). However, this question should be relatively easy to answer from their database and is likely to be at least six months because current USPHS/IDSA guidelines advocate monitoring CD4+ titers and HIV-RNA loads every three months.
This promising study and others like it will continue to expand our knowledge and enable physicians to safely modify practice strategies in a rational, evidence-based manner.