Randomized study of didanosine monotherapy and combination therapy with zidovudine in hemophilic and nonhemophilic subjects with asymptomatic human immunodeficiency virus-1 infection

To evaluate the safety and efficacy of didanosine (ddI) monotherapy and three different combinations of zidovudine (ZDV) and ddI in asymptomatic human immunodeficiency virus-1 (HIV-1) infection, we conducted an open- label, phase I/II study in 126 asymptomatic HIV-1-infected hemophilic and nonhemophilic subjects with a CD4 count of 200 to 500/mm³ stratified for prior zidovudine treatment and baseline CD4 count. Study arms included arm A, low-dose combination (ZDV 150 mg and ddl 134 mg, daily); arm B, moderate- dose combination (ZDV 300 mg and ddl 334 mg, daily); arm C, high-dose combination (ZDV 600 mg and ddl 500 mg, daily), and arm D, ddl monotherapy (ddl 500 mg, daily). Earlier, more frequent hepatotoxicity was experienced by hemophilic subjects (P = .008), but there were no differences in toxicity between treatment arms (P = .51), nor were there any differences in the rate of development of clinical endpoints by treatment (P = .41). Smaller median CD4 increases occurred over the first 12 weeks for arms A and D, 44/mm³ and 42/mm³, than arms B and C, 105/mm³ and 114/mm³, respectively, (P = .015). Hemophilia status (P = .0004) and prior ZDV experience (P = .044) independently predicted weaker CD4 responses during the first 12 weeks of treatment. Using a regression model end adjusting for hemophilia status, prior ZDV treatment, and baseline CD4, there was a significant reduction in quantitative vital load from baseline by week 12 for all treatment arms combined (P = .0001), with significantly lower median percent reduction for arm A (56.3%) than arms B, C, and D (94.6%, 98.5%, and 91.9%, respectively, P = .015). Although greater hepatoxicity and weaker CD4 responses occur in hemophilic subjects, didanosine monotherapy and combination therapy with zidovudine are safe and effective in asymptomatic HIV-1-infected patients.