Reductions in HIV-1 disease progression for zidovudine/lamivudine relative to control treatments

OBJECTIVES: Four randomized double-blind trials have demonstrated that zidovudine/lamivudine (ZDV/3TC) reduces HIV RNA and raises CD4 counts relative to control treatments (ZDV or ZDV/zalcitabine (ddC)]. A meta-analysis of the clinical events in these trails was conducted to determine whether treatment with ZDV/3TC was also associated with a clinical benefit. DESIGN: The four trials, ZDV/3TC versus ZDV (NUCA3001, NUCB3001, NUCB3002) or versus ZDV/ddC (NUCA3002), were run concurrently, using the same doses of ZDV and 3TC. SETTING: Investigational sites in Europe and North America. PATIENTS: The trials recruited 972 HIV-1-positive, male and female patients aged > or = 18 years, with CD4 counts of 100-500 cells x 10(6)I. Two trials were for ZDV-naive patients and two were for ZDV pre-treated patients. MAIN OUTCOME MEASURES: Progression to first new Centers for Disease Control and Prevention (CDC) B or C event was compared between all ZDV/3TC arms and all control (ZDV, ZDV/ddC) arms. RESULTS: A total of 118 patients progressed to a first new CDC B/C event during the four trials, while 28 progressed to a new CDC event. Meta-analysis of the trials showed a 49% reduction in progression to new CDC B/C events (relative risk, 0.509; 95% confidence interval, 0.365-0.710; P < 0.0001) and a 66% reduction in progression to new CDC C events (relative risk, 0.344; 95% confidence interval, 0.169-0.700; P = 0.003) for the ZDV/3TC patients relative to the control patients. Reductions in progression to CDC B/C disease were seen in subgroups of naive and pre-treated patients, those with high and low CD4 counts and symptomatic and asymptomatic patients. CONCLUSIONS: ZDV/3TC combination treatment delays the progression of CDC B/C disease compared with control treatments. In view of the low incidence of CDC C events, the results for progression to CDC C disease should be interpreted with caution.