Outcomes after allogeneic hematopoietic cell transplant in patients diagnosed with blast phase of myeloproliferative neoplasms: A retrospective study from the Chronic Malignancies Working Party of the European Society for Blood and Marrow Transplantation

Abstract

AbstractAllogeneic hematopoietic cell transplant (allo‐HCT) provides the only potential route to long‐term remission in patients diagnosed with blast phase transformation of myeloproliferative neoplasm (BP‐MPN). We report on a large, retrospective European Society for Blood and Marrow Transplantation registry‐based study of BP‐MPN patients undergoing allo‐HCT. BP‐MPN patients undergoing first allo‐HCT between 2005 and 2019 were included. A total of 663 patients were included. With a median follow‐up of 62 months, the estimated 3‐year overall survival (OS) was 36% (95% confidence interval [CI], 32–36). Factors associated with lower OS were Karnofsky Performance Score (KPS) <90 (hazard ratio [HR] 1.65, p < .001) and active disease at allo‐HCT (HR 1.45, p < .001), whereas patients undergoing allo‐HCT more recently associated with a higher OS (HR 0.96, p = .008). In a selected patient's population, the 3‐year OS of patients undergoing allo‐HCT in complete response (CR) and with a KPS ≥90 was 60%. KPS < 90 (HR 1.4, p = .001) and active disease (HR 1.44, p = .0004) were associated with a lower progression‐free survival (PFS). Conversely, most recent allo‐HCT associated with a higher PFS (HR 0.96, p = .008). Active disease at allo‐HCT (HR 1.34, p = .03) was associated with a higher cumulative incidence of relapse (RI) and allo‐HCT in earlier calendar years (HR 0.96, p = .02) associated with a lower RI. Last, KPS < 90 (HR 1.91, p < .001), active disease (HR 1.74, p = .003) and allo‐HCT from mismatched related donors were associated with a higher non‐relapse mortality (HR 2.66, p = .003). In this large series of BP‐MPN patients, about one third were alive at 3 years after transplantation. Patients undergoing allo‐HCT in the more recent era, with a KPS ≥90 and in CR at transplant had a better prognosis.