Safety and efficacy of reduced doses of ritonavir (RTV) plus saquinavir (SQV) in the treatment of AIDS patients in Brazil

ABSTRACT

The use of reduced doses of Ritonavir (RIT) and Saquinavir (SQV) is considered a potent alternative in treating patients infected by HIV-1. We tested a combination of 300mg of RIT plus 600mg of SQV, twice daily, in association with two reverse transcriptase inhibitors to treat AIDS patients for a period of 6 monts. Evaluation of HIV-1 RNA plasma levels, CD4+/CD8+ cell count and biochemical/hematological parameters (liver enzymes, serum electrolytes, creatinin, blood glucose, uric acid, white blood cell count, platelet count, and hemoglobin level) were performed after 30, 90 and 180 days of therapy. Clinical failure and adverse reactions were also recorded in order to assess safety and efficacy of the treatment. A total of 30 AIDS patients (25 male; 5 female) were enrolled in the study. Eight patients discontinuede the therapy due to intolerance, 2 patients presented clinical failure (onset of AIDS defining events during the study period), 2 patients were excluded due to protocol violation. Five patients tolerated only a lower dose of RIT (400mg/day). Patients who completed 6 months of therapy had a drop in viral load from 4.8ñ.7log10median4.9log) to 3.4ñ1.0log10(median 2.6log), and an increase in CD4+ count from 109ñ86 cells/ml(median 84 cells/ml) to 249ñ114 cells/ml(median 265cells/ml), compared to baseline values. However, patients who used a lower dose of RIT (400mg/day) had a less impressive drop in viral load values(mean0.6log10RNA copies/ml) when compared with those using the 600mg/day of the drug(mean 2.4log10). The percentage of patients presenting undetectable levels of HIV-1 RNA in plasma was quite different for the 2 groups 92 percent of patients with a viral load <400 RNA copies/ml were using 600mg of RIT. The combination of reduced doses of RIT and SQV reduced viral load >1.0log10 after 6 months in 83 percent of study patients. The dose of 600mg/day of RIT was more effective in reducing viral load than 400mg/day, but was less well-tolerated. CD4+ cell counts increased in all patients regardless of the RIT dose used.