No advantage of a rotational continuation phase in acute lymphoblastic leukemia in childhood treated with a BFM back-bone therapy.

ABSTRACT

BACKGROUND: Our aim was to compare two different schedules of maintenance in pediatric acute lymphoblastic leukemia (ALL) treated with a BFM-based therapy, in a randomized study an Arm with 6-MP + MTX (with or without vincristine and dexamethasone pulses) versus a more intensive continuation phase. PROCEDURE From January 1996 to November 2002, 429 eligible children with ALL were enrolled in a protocol with BFM-based back-bone, followed by a randomized continuation phase in standard (SRG) and intermediate (IRG) risk groups. Patients were randomized between Arms A and B for SRG and B or C for IRG. Arms A and C consisted of 6-MP and MTX and in Arm C, six pulses of VCR and dexamethasone were added. Arm B combined four pairs of drugs rotated weekly. All risk-groups received maintenance until completing 2 years of therapy from diagnosis. RESULTS: With a median follow-up of 138 (range 96-178) months, the overall pEFS (SE) was 72 (6)% for all patients and the different risk groups showed SRG 85 (3)%, IRG 71 (1)%, and HRG 42 (7)% (P-value ≤ 0.0001). The pDFS (SE) according to the assigned arm of maintenance was, for Arm A 89 (3)% and for Arm B 85 (4)% in SRG, and, for Arm B 77 (4)% and for Arm C 75 (4)% in IRG, at 10 years follow-up. There were no statistically significant differences in outcome between arms of maintenance for both risk groups. CONCLUSIONS: In protocols with initial BFM-based strategy, a more intensive continuation phase did not benefit any risk group of patients.