About The Study

This study compared the effect of two- and three-drug regimens of AZT, ddI and nevirapine, on both viral load and CD4 counts in HIV-positive individuals.

Study Approach

This was a double-blinded study (neither doctors nor volunteers knew which therapy volunteers received). Participants were randomly assigned to receive one of three treatments: nevirapine plus AZT; AZT plus ddI; or nevirapine plus AZT plus ddI. The drug doses were: AZT (600 mg/day), ddI (400 mg/day, if weight was greater than or equal to 60 kgs), and nevirapine (200 mg/day for 14 days followed by 200 mg twice daily). All participants completed 10 months of follow-up.

Study population

One hundred and twenty HIV-positive people from Australia, Canada, Italy and the Netherlands (more than half from Canada) were enrolled. All volunteers had taken no prior antiretroviral treatment, had CD4 counts between 200 and 600, and had no AIDS-defining illnesses. Ninety-two percent of participants were males, 93% were white and the median CD4 count was 340 at the start of the study.


Average viral load was 4.3 logs and it decreased by more than 2 logs within one month of starting the study drugs. Three percent of participants experienced a severe rash associated with the study drugs.


Preliminary results indicate a substantial decrease in viral load when two- and three-drug combinations of AZT/ddI/nevirapine are used among volunteers who had taken no prior antiretroviral treatment. The combinations were also generally well-tolerated. Further analyses will be completed in the near future.