The UK Medical Research Council CLL trials 1 and 2

The Medical Research Council (MRC) Working Party on Leukaemia in Adults has conducted two randomised trials in CLL since 1978. CLL 1 ran from 1978 to 1984 and recruited 660 eligible patients. The number of males was twice the number of females and the distribution of cases by stage was different in the sexes: 58% of females were stage A, 25% stage B and 17% stage C; in males the proportions for stages A, B and C were 40%, 30% and 30% respectively. The most important prognostic factor was stage (A, B, C), followed by age, sex and response to treatment, which were confirmed as independent variables by stratified log-rank and Cox multivariate analyses. Causes unrelated to CLL accounted for 28% of all deaths and were more common in older patients and in stage A disease. No significant difference was observed between the CLL 1 treatment schedules: chlorambucil, penta Cop and splenic irradiation (SI), although a somewhat better survival was seen for patients treated by SI. (When CLL deaths only were considered SI appeared superior to chlorambucil (p less than 0.05]. CLL 2 started in 1984 and is still accruing patients; 556 had been entered by July 1988. This trial compares early versus delayed therapy for stage A, chlorambucil with and without prednisolone for stages B and C in patients with a small or nonpalpable spleen, and SI vs chlorambucil with or without prednisolone for stages B and C in patients with a larger spleen (greater than or equal to 5 cm).(ABSTRACT TRUNCATED AT 250 WORDS)