TreatmentUpdate 69, Volume 8, No 5; July 1996
Sean Hosein

Researchers in the European Union and Australia compared the effects of a combination of two anti-HIV drugs, namely AZT and nevirapine, versus AZT alone. All subjects were supposed to have used between 500 and 600 mg/day AZT for "at least 6 months" before entering this study. Researchers recruited 49 subjects (13 female, 36 male) at least half of whom were free from symptoms of HIV infection. Researchers randomly assigned 24 subjects to receive continued AZT and 25 others to receive nevirapine and AZT (combination group). The average CD4+ cell count of subjects in the AZT only group was 210 cells and in the combination group it was 195 cells. This difference was not statistically significant.

All subjects received AZT at either 500 or 600 mg/day. In the combination group doctors gave the subjects "200 mg/day nevirapine for two weeks followed by 400 mg/day for 26 weeks." By the 28th week, subjects who had been assigned to receive only AZT could receive the combination if they wished. During the study subjects in the AZT only group who had increasing levels of HIV in their blood could also receive nevirapine.

Results - CD4+ cells

Subjects in the combination group had an increase of 34 cells by the 4th week of the study, which was statistically significant; that is, not likely due to chance alone. By the 28th week their average CD4+ cell count fell 40 cells below their pre-study level. Subjects who received AZT alone had, on average, about 10 less CD4+ cells than when they started. The average CD4+ cell count remained at this level by the 28th week.

Results - infections

Although 63% of subjects in the AZT only group and 40% of subjects in the combination group developed worsening symptoms of HIV infection, this difference was not statistically significant. Indeed, 20% of subjects on combination developed AIDS as did 13% of the AZT group, but this difference was also not statistically significant.

Results - HIV

By the 6th week, subjects on the combination had a dramatic decrease in the amount of HIV in their blood -- 8 times less than their pre-study levels, a statistically significant event. By the 12th week levels of HIV rose to their pre-study levels. Subjects on AZT alone had increasing levels of HIV in their blood.

Toxicity

Eight subjects receiving nevirapine developed "rash and fever". For 7 subjects the rash occurred within the first 4 weeks of the study. In 3 subjects the rash was mild and cleared within 1 week despite continued use of nevirapine. Once doctors stopped giving the remaining 5 subjects nevirapine, the rash and fever cleared.

In this study, use of nevirapine did not appear to provide any "significant" protection from the development of AIDS. In another study cited by this research team, use of AZT with ddI and nevirapine in subjects who used AZT before entering that study, did not provide any greater protection against the onset of symptoms of HIV infection than the combination of AZT and ddI.

REFERENCES:

1. Carr A, Vella S, de Jong MD, et al. A controlled trial of nevirapine plus Zidovudine versus Zidovudine alone in p24 antigenaemic HIV-infected patients. AIDS 1996;10(6):635-641.

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Copyright © 1996 - TreatmentUpdate. Reproduced with permission. Reproduction of this article (other than one copy for personal reference) must be cleared through the Editor, The Canadian AIDS Treatment Information Exchange, 555 Richmond St. West, Suite 505, Box 1104, Toronto, ON, M5V 3B1 • Phone: 416-203-7122 • Toll Free: 1-800-263-1638 • Fax: 416-203-8284  http://www.catie.ca