Treatment outcomes following leukemic transformation in Philadelphia-negative myeloproliferative neoplasms

Leukemic transformation (LT) is a rare but fatal complication of Philadelphia-negative myeloproliferative neoplasms (MPNs) for which optimal treatment strategies are not known. At our center, we have adopted a treatment approach for LT where patients within the transplant age group who have a reasonable fitness level are treated with curative intent and offered induction chemotherapy. Subsequently, those who respond and have a suitable donor are considered for allogeneic hematopoietic cell transplantation (HCT). In this study, we evaluated the clinical outcomes of this treatment approach in 75 patients with LT. The 2-year overall survival (OS) from the time of LT was 15%. A total of 39 patients (52%) were treated with curative intent (induction ± HCT) and had a 2-y OS of 26% compared with 3% in those noncuratively treated (P < .0001). In the curative intent group, 18 individuals (46%) achieved complete remission (CR) or CR with incomplete recovery and 12 (31%) reverted to a chronic MPN phase, with 17 patients undergoing HCT. Survival of patients posttransplant was significantly improved compared with those who responded to induction but were not transplanted (2-y OS of 47% vs 15%; P = .03). Thus, induction chemotherapy followed by HCT has the potential for long-term disease control in select patients with LT preceded by a MPN.