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Comprehensive clinical-molecular transplant scoring system for myelofibrosis undergoing stem cell transplantation

Nico Gagelmann, Markus Ditschkowski, Rashit Bogdanov, Swan Bredin, Marie Robin, Bruno Cassinat, Rabia Shahswar, Felicitas Thol, Michael Heuser, Gerard Socié, Dietrich Beelen, Ioanna Triviai, Anita Badbaran and Nicolaus Kröger

Key points

  • The myelofibrosis transplant scoring system includes clinical-molecular and transplant-specific factors predicting posttransplant outcome.

  • The MTSS is applicable to primary and post-ET/PV myelofibrosis reflecting posttransplant outcome better than disease-specific systems.

Abstract

Allogeneic hematopoietic stem cell transplantation is curative in myelofibrosis and current prognostic scoring systems aim to select patients for transplantation. Here, we aimed to develop a prognostic score to determine prognosis after transplantation itself using clinical, molecular and transplant-specific information of a total of 361 myelofibrosis patients. Of these, 205 patients were used as a training cohort to create a clinical-molecular myelofibrosis transplant scoring system (MTSS), which was then externally validated in a cohort of 156 patients. Multivariable analysis on survival identified age ≥ 57 years, Karnofsky performance status < 90%, platelet count < 150 x 109/L and leukocyte count > 25 x 109/L prior to transplantation, HLA-mismatched unrelated donor, ASXL1 mutation and non-CALR/MPL driver mutation genotype being independent predictors of outcome. The uncorrected concordance index for the final survival model was 0.723, and bias-corrected indices were similar. Risk factors were incorporated into a 4-level MTSS: low (score of 0-2), intermediate (score of 3-4), high (score of 5), and very high (score of > 5). The 5-year survival according to risk groups in the validation cohort was 83% (95% CI, 71-95%), 64% (95% CI, 53-75%), 37% (95% CI, 17-57%), and 22% (95% CI, 4-39%), respectively (p < 0.001). Increasing score was predictive of non-relapse mortality (p < 0.001) and remained applicable to primary (0.718) and post-ET/PV myelofibrosis (0.701) improving prognostic ability in comparison to all currently available disease-specific systems. In conclusion, this myelofibrosis transplant score (MTSS) predicts outcome of primary and post-ET/PV myelofibrosis patients undergoing allogeneic stem cell transplantation.

  • Submitted December 10, 2018.
  • Accepted February 8, 2019.