Sixty-one adults aged <55 years with acute lymphoblastic leukaemia (ALL) in first bone marrow relapse were enrolled in an Italian cooperative study (ALL R-87 protocol) from 12 GIMEMA Institutions. The treatment programme consisted of: (1) an induction phase with intermediate-dose cytarabine (IDARA-C 1 g/m2, 6 h daily infusion x 6 d) plus idarubicin (IDA; 5 mg/m2/d x 6 d) and prednisone (40 mg/m2/d x 21 d), (2) a consolidation phase followed by (3) bone marrow transplant (BMT). Median first complete remission (CR) duration was 8.5 months (range 1-54 months). 34/61 patients achieved CR (56%); 24 (39%) failed to respond and three (5%) died during induction. Most responders (24 patients) could not enter the BMT programme; 15 relapsed early (median time to relapse 2 months); nine were withdrawn due to toxicity and one died in CR of infection. Nine of the 34 CRs underwent BMT (five autologous and four allogeneic). Three of the four allotransplanted patients are alive in continuous CR at 22, 43 and 63 months; only one of the five who underwent an autologous BMT is alive in CR at 46 months. The estimated disease-free survival (DFS +/- SE) at 36 months was 0.16 +/- 0.08 for all responders. Univariate analysis showed that previous therapy was the only prognostic factor influencing DFS. The estimated probabilities of event-free survival (EFS +/- SE) and survival +/- SE at 37 months were 0.09 +/- 0.04 and 0.10 +/- 0.04, respectively. The EFS was significantly better in patients with a preceding CR > or = 24 months, compared to those with a shorter first remission. Our results confirm the tolerance and efficacy of IDARA-C plus IDA in inducing CR in poor-risk adult ALL. Even though the number of transplanted patients was small, allogeneic BMT seems to give a real opportunity of cure in this category of patients.