Long-term remission of Philadelphia chromosome–positive acute lymphoblastic leukemia after allogeneic hematopoietic cell transplantation from matched sibling donors: a 20-year experience with the fractionated total body irradiation–etoposide regimen

Allogeneic hematopoietic cell transplantation (HCT) is the only known curative modality for patients with Philadelphia chromosome–positive acute lymphoblastic leukemia (Ph+ ALL). Sixty-seven patients with HLA-matched sibling donors received fractionated total body irradiation (FTBI) and high-dose VP16, whereas 11 patients received FTBI/VP16/cyclophosphamide, and 1 patient received FTBI/VP16/busulfan. The median age was 36 years. At the time of HCT, 49 patients (62%) were in first complete remission (CR1) and 30 patients (38%) were beyond CR1 (> CR1). The median follow-up was 75 months (range, 14-245 months). The 10-year overall survival for the CR1 and beyond CR1 patients was 54% and 29% (P = .01), respectively, and event-free survival was 48% and 26% (P = .02), respectively. There was no significant difference in relapse incidence (28% vs 41%, P = .28), but nonrelapse mortality was significantly higher in the beyond CR1 patients, (31% vs 54%, P = .03, respectively). By univariate analysis, factors affecting event-free and overall survival were white blood cell count at diagnosis (< 30 × 109/L vs > 30 × 109/L) and disease status (CR1 vs > CR1). The median time to relapse for CR1 and for beyond CR1 patients was 12 months and 9 months, respectively. Our results indicate that FTBI/VP16 with or without cyclophosphamide confers long-term survival in Ph+ ALL patients and that disease status at the time of HCT is an important predictor of outcome.