Efficacy and Tolerability of Ritonavir in Children with HIV Infection: Follow-up at 1 Year † 918

Objective: To determine the clinical efficacy and tolerability of ritonavir in HIV infected children. Methods: The dose of ritonavir was 250 mg/m²/dose po BID. Viral load, CD4 count, and percent ideal weight for height were collected at baseline and then every 3 months. Data regarding tolerability and reason for discontinuation were also recorded. Data were compared to baseline using the Wilcoxon matched pairs signed-ranks test and significance was defined as ≤ 0.05. Results: Since October 1996, ritonavir therapy has been initiated in 16 children. Therapy was discontinued in 3 children: a 14.5 year old male discontinued therapy after 3 months because of peripheral neuropathy, a 2 year old female discontinued it after 5 months because of excessive emesis and refusal to take the suspension and a 6 year old female had a change in regimen after 8 months because of uncontrolled simultaneous infection with EBVand HIV. In the remaining 13 patients, the mean age was 7.1± 4.6 years, 35% were male and the median length of ritonavir therapy was 12 months (range 5 to 14 months). The median CD4 (25th,75th percentile) cells/mL increased from a baseline of 400 (75,862) to 401 (207,1016) at 3 months, 1104 (693,1481) at 6 months, 504 (372,952) at 9 months and 696 (427,1080) at 12 months (all p<0.05). Similarly, the medial viral load (25th,75th percentile) log₁₀ copies/mL decreased from a baseline of 4.4 (3.7,5.2) to 2.6 (2.2,3.9) at 3 months, 3.1(2.3,3.8) at 6 months and 2.7(2.5,4.1) at 9 months (all p<0.05). The viral load at 12 months was not significantly lower at 3.0(2.5,5.0) log₁₀ copies/mL. There were no significant differences in percent ideal weight for height at 3, 6, 9 or 12 months. Other than the 3 patients who discontinued therapy, ritonavir was well tolerated by the other 13 except for some transient emesis in 2 patients. Conclusions: In pediatric HIV, 12 months of ritonavir therapy is associated with improved CD4 and initially a lower viral load. It is unclear if the non-significantly lower median viral load at 12 months represents loss of antiviral activity or insufficient sample size. In our population, 19% of patients required discontinuation of the medication but in the others, ritonavir was well tolerated.