The Efficacy and Safety of Zidovudine Alone or As Cotherapy with Acyclovir for the Treatment of Patients with AIDS and AIDS-related Complex: a Double-blind Randomized Trial. European-Australian Collaborative Group

Objective: To evaluate the efficacy and safety of zidovudine (ZDV) at a maintenance dose of 250 mg every 6 h alone or as cotherapy with acyclovir (ACV; 800 mg every 6 h) as treatment for AIDS and AIDS-related complex (ARC).

Design: Double-blind, randomized, placebo-controlled clinical trial of up to 1 year's therapy.

Setting: Teaching hospital ambulatory clinics in eight European countries and Australia.

Subjects: A total of 131 patients with AIDS and 134 with ARC were enrolled and followed from 1986 to 1988.

Main Outcome Measures: Time to development of AIDS-defining opportunistic infections and AIDS-associated neoplasms, survival assessed at 1 year after entry, performance status, body weight, CD4+ cell counts.

Results: During the study period, 46 (36%) ZDV recipients and 37 (27%) cotherapy recipients developed opportunistic infections. The probability of an ARC patient progressing to AIDS (1982 Centers for Disease Control criteria) was 0.18 and 0.15 [95% confidence interval (CI) for difference, -0.17 to 0.11] for the ZDV alone and cotherapy recipients, respectively. After excluding patients who experienced an opportunistic infection during the first 4 weeks of therapy, the probability was 0.13 and 0.099 (95% CI for difference, -0.16 to 0.10) for the ZDV and cotherapy recipients, respectively. Thirty-six patients treated with single-agent therapy [28 (41%) AIDS and eight (12%) ARC patients] and 15 cotherapy recipients [13 (21%) AIDS and two (3%) ARC patients] died during the study. There was a significant difference in time to death between the cotherapy and ZDV alone groups for both AIDS (P = 0.014) and ARC (P = 0.045) patients, with cotherapy patients surviving longer. Infections related to herpesviruses, but not cytomegalovirus, were reduced in patients receiving ACV therapy. CD4+ cell counts in both arms generally increased initially and then declined. Forty-six per cent of patients in the ZDV group (59% of AIDS and 31% of ARC patients) and 52% of patients in the cotherapy group (69% of AIDS and 34% of ARC patients) experienced bone-marrow suppression. Red cell transfusions were administered to 33% of ZDV alone recipients and 34% of cotherapy recipients.

Conclusion: These data show that the addition of high-dose ACV cotherapy to ZDV for patients with AIDS and advanced ARC results in a statistically significant improvement in survival with minimal increase in the risk of toxicity.