didanosine and Weight-Gain

The safety and antiretroviral effects of didanosine and stavudine in combination were evaluated in 86 people infected with HIV with CD4 counts between 200 and 500 cells/mm3 who had received <7 days of prior nucleoside analogue antiretroviral treatment. Patients were randomized to receive blinded treatments with one of five weight-adjusted, twice-daily regimens of didanosine and stavudine (100 + 10 mg, 100 + 20 mg, 100 + 40 mg, 200 + 20 mg, and 200 + 40 mg) for up to 1 year. Dosages were adjusted appropriately for patients weighing <60 kg and reduced in response to adverse effects. No clear dose-related differences among treatment groups were detected with regard to suppression of plasma HIV RNA level or reduction in infectious titers in peripheral blood mononuclear cells (PBMCs), improvement in CD4 count, or adverse effects. However, trends toward greater decreases in viral load and increases in CD4 count were detected when treatment groups containing the full recommended dosage of one or both agents (high-dose subgroup; arms 3, 4, and 5) were compared with the groups receiving lower dosages. At 28 weeks the mean log 10 HIV RNA decrease was 1.12 (n = 52) and at 52 weeks it was 0.97 (n = 32). Combination therapy was well tolerated, with no apparent dose-related adverse effects. Peripheral neuropathy occurred in 2 of 86 (2.3%) of patients. Didanosine and stavudine together appear to be a good nucleoside analogue foundation for aggressive triple- or quadruple-drug therapy. Full therapeutic doses of each of these two agents should be used to achieve optimal suppression of HIV replication.

Topics: Adult; Aged; Anti-HIV Agents; CD4 Lymphocyte Count; Didanosine; Dose-Response Relationship, Drug; Double-Blind Method; Drug Therapy, Combination; Female; HIV; HIV Infections; Humans; Male; Middle Aged; Peripheral Nervous System Diseases; RNA, Viral; Stavudine; Viral Load; Virus Replication; Weight Gain

The relation between the average steady-state plasma concentration (Cpss) of didanosine and selected measures of efficacy, such as CD4 cell count, p24 antigenemia, and weight gain, was evaluated in patients participating in a phase 1 safety and pharmacokinetics study. All patients were diagnosed as having AIDS or severe AIDS-related complex. These individuals first received intravenous didanosine for 2 weeks at doses of 0.8-33 mg/(kg.d) and then took the drug orally at twice the intravenous dose. Cpss values were calculated on the basis of apparent oral clearance after 4 weeks of oral administration and average daily dose over the first 12 weeks of the study. These data were available for 61 patients enrolled at three clinical sites. High values for Cpss were strongly correlated with an increase in CD4 count (P = .006), a decrease in serum levels of p24 antigen (P = .006), and weight gain (P = .0001) at week 12. Logistic regression analysis was used to assess the influence of Cpss on response (as judged by the three criteria just mentioned) after adjustment for other potential factors related to infection with human immunodeficiency virus. The baseline CD4 cell count and the status with regard to prior zidovudine therapy were related to the CD4 response. However, the odds that a response would include all three parameters were nearly twice as high when the Cpss value increased by twofold.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Acquired Immunodeficiency Syndrome; Administration, Oral; Adult; AIDS-Related Complex; Biomarkers; CD4-Positive T-Lymphocytes; Didanosine; Female; HIV Core Protein p24; Humans; Infusions, Intravenous; Leukocyte Count; Male; Middle Aged; Regression Analysis; Weight Gain

Ribavirin has been reported to enhance the activity of ddI against HIV. We explored this enhancement of antiviral activity in Rauscher murine leukemia virus (RMuLV) models in vitro and in vivo. The significant finding in these studies was that combinations of the drugs exhibited virus titer reductions that were greater than would be expected if the drug interactions were simply additive. These effects were designated synergistic by the method of Prichard and Shipman (Prichard, M.N. and Shipman, C., Jr. (1990). A three-dimensional model to analyze drug-drug interaction, Antiviral Res. 14, 181-206). In addition to the antiviral synergy, we also observed some synergistic toxicity in the animal model.

Topics: Animals; Cell Line; Didanosine; Drug Synergism; Leukemia, Experimental; Male; Mice; Rauscher Virus; Retroviridae Infections; Ribavirin; Tumor Virus Infections; Weight Gain