The Safety and Efficacy of Zidovudine (AZT) in the Treatment of Subjects with Mildly Symptomatic Human Immunodeficiency Virus Type 1 (HIV) Infection

TLDR

The study aimed to evaluate the efficacy and safety of early zidovudine therapy in mildly symptomatic HIV‑1 patients. A multicenter, double‑blind, randomized, placebo‑controlled trial enrolled 711 subjects, assigning 360 to zidovudine (200 mg q4h) and 351 to placebo, with a median 11‑month follow‑up. In patients with CD4 counts of 200–500 cells/µL, zidovudine reduced progression events to 12 versus 34 in placebo (RR 3.23, P = 0.0002), produced sustained CD4 increases through 52 weeks, lowered HIV antigen levels, and caused only modest anemia and neutropenia, while higher CD4 strata showed minimal benefit.

Abstract

To evaluate the efficacy and safety of zidovudine early in the treatment of human immunodeficiency virus type 1 (HIV) infection.A double-blind, randomized, placebo-controlled trial with subject stratification by pretreatment CD4 T lymphocyte counts.Multicenter trial at AIDS Clinical Trial units.Seven hundred eleven subjects with mildly symptomatic HIV infection.Three hundred fifty-one subjects were assigned to placebo and 360 to zidovudine, 200 mg orally every 4 hours. The median duration of follow-up was 11 months.Fifty-one subjects developed the acquired immunodeficiency syndrome (AIDS), advanced AIDS-related complex, or death as a first critical event. For the stratum of subjects with more than 200 but less than 500 CD4 T lymphocytes/mm3 before treatment, 34 events occurred in placebo recipients and 12 in zidovudine recipients (P = 0.0002; relative risk [RR] estimate, 3.23 [95% CI, 1.67 to 6.24]). For the stratum of subjects with 500 to 799 CD4 T lymphocytes/mm3 before treatment, 2 events occurred in placebo recipients and 3 in zidovudine recipients. Candidiasis at study entry independently increased the risk for having an event (P = 0.005; RR estimate, 2.3 [95% CI, 1.29 to 4.12]); HIV antigenemia at study entry also increased this risk (P = 0.01; RR estimate, 2.1 [95% CI, 1.2 to 3.8]). Significant differences between the treatment groups in CD4 T-lymphocyte counts occurred in subjects with more than 200 but less than 500 CD4 T lymphocytes/mm3 after 4 weeks of therapy (P = 0.002). Differences persisted through week 52. Less prominent changes occurred in subjects with 500 or more CD4 T lymphocytes/mm3. Serum levels of HIV antigen decreased significantly in zidovudine recipients. Serious anemia and neutropenia occurred in 5% and 4% of zidovudine recipients, respectively, and in 0% and 1% of placebo recipients, respectively.Zidovudine delayed progression of HIV disease and produced little toxicity in subjects with mildly symptomatic HIV disease and less than 500 CD4 T lymphocytes/mm3.