Allogeneic bone marrow transplantation for children with acute lymphoblastic leukemia in first remission: a cooperative study of the Groupe d'Etude de la Greffe de Moelle Osseuse.

Thirty-two children ranging in age from 1.5 to 16 years with poor-prognosis acute lymphoblastic leukemia (ALL) were treated with myeloablative immunosuppressive therapy consisting of cyclophosphamide (CPM) and total body irradiation (TBI) followed by allogeneic bone marrow transplantation (BMT) while in first complete remission (CR). The main reasons for assignment to BMT were WBC count greater than 100,000/microL, structural chromosomal abnormalities, and resistance to initial induction therapy. All children were transplanted with marrow from histocompatible siblings. Twenty-seven patients are alive in first CR for 7 to 82 months post-transplantation (median, 30 months). The actuarial disease-free survival rate is 84.4% (confidence interval, 7.2% to 29%) and the actuarial relapse rate is 3.5% (confidence interval, 0.9% to 13%). Four patients died of transplant-related complications, 16 developed low-grade acute graft-v-host disease (GVHD), and six developed chronic GVHD. The very low incidence of relapse (one of 28 long-term survivors) precluded the determination of the prognostic significance of the different poor-outcome features. Moreover, two infants treated with busulfan, CPM, and cytarabine (Ara-C) relapsed promptly in the marrow. In summary, as a means of providing long-term disease-free survival and possible cure, BMT should be considered for children with ALL presenting poor-prognostic features, particularly certain chromosomal translocations [t(4;11), t(9;22)], very high WBC counts, notably if associated with a non-T immunophenotype, and, perhaps, a poor response to initial therapy with corticosteroids (CS), or infants less than 6 months of age.