Comparison of atovaquone and azithromycin with trimethoprim- sulfamethoxazole for the prevention of serious bacterial infections in children with HIV infection

Background. Trimethoprim-sulfamethoxazole (TMP-SMZ) has been used extensively for the prevention of Pneumocystis carinii (also referred to as "Pneumocystis jiroveci") pneumonia (PCP) and other opportunistic infections in human immunodeficiency virus (HIV)-infected children. Because the efficacy of TMP-SMZ for treatment of bacterial infections is limited, it is sometimes poorly tolerated, and there is risk of emergence of drug-resistant strains associated with widespread use, we evaluated a regimen that included atovaquone and azithromycin. Methods. A randomized, double-blind, placebo-controlled trial was designed to determine whether atovaquone- azithromycin had equivalent efficacy to TMP-SMZ for the prevention of serious bacterial infections and to compare the long-term tolerance, PCP breakthrough rates, and nonserious bacterial infection rates among HIV-infected children aged 3 months to 19 years. Children qualified for PCP prophylaxis (on the basis of Centers for Disease Control and Prevention recommendations) were randomized to receive atovaquone-azithromycin or TMP-SMZ daily for ≥2 years. Results. Data from 366 of the 369 eligible patients (median duration of follow-up, 3 years) showed that the estimated rates of serious bacterial infection-related events were lower among atovaquone-azithromycin recipients than among TMP-SMZ recipients (17.3 vs. 24.2 events per 100 patient-years; difference, 6.9 events per 100 patient-years; 95% confidence interval [CI], -0.22 to 14.12). Rates for all end points (serious bacterial infection, PCP, Mycobacterium avium complex infection, and serious and nonserious bacterial infection-related deaths) were 19.7 and 27.7 events per 100 patient-years, respectively (difference, 7.9 events per 100 patient-years; 95% CI, -0.28 to 15.54 events per 100 patient-years). The results marginally favored atovaquone-azithromycin therapy statistically. Atovaquone-azithromycin and TMP-SMZ therapies had similar adverse event profiles. Conclusions. We conclude that, in HIV-infected children, atovaquone-azithromycin is as effective as TMP-SMZ for the prevention of serious bacterial infections and is similarly tolerated.