Role of molecular alterations in transplantation decisions for patients with primary myelofibrosis

• MIPSS70 high patients benefit from transplantation

• MIPSS70 intermediate patient may benefit from transplantation if their MTSS score is low or intermediate

The aim of our study was to analyze the potential survival benefit associated with HSCT according to clinico-biological scores which incorporate molecular data (MIPSS70 and MIPSS70+V2) to facilitate decision-making in this context. One transplant (n=241) and one non-transplant cohorts (n=239) were used to test the hypothesis that PMF patients with higher risk molecular score benefit from HSCT. A weighted propensity score was applied to balance confounding factors with the transplanted cohort as reference. Weighted Cox proportional hazard models and logistic regression analyses were performed. 105 non-transplanted patients could be matched to the 239 transplanted patients. Mean age in transplanted and non-transplanted matched patients was 55.5 and 57.9 years. Blood cell count and DIPSS score distribution were similar in both groups. HSCT was associated with a higher 6-year OS rate in intermediate-2 (60.1% versus 41.5%) and high-risk DIPSS patients (44.4% versus 6.55%), high-risk MIPSS70 (46.5 versus 23.9%), high-risk (73.2% versus 39.7%) or very high-risk MIPSS70V2 (51.8% versus 24%). Intermediate MIPSS70 patients have an advantage of survival with HSCT only when their MTSS were low or intermediate. Transplanted patients had an increased mortality risk the first year but a significant benefit with HSCT after the one-year landmark was observed in higher risk patients. This study confirms that similar to DIPSS, MIPSS70 and MIPSS70+V2 risk score in addition to MTSS can be used to determine which patients with primary myelofibrosis have survival benefit from HSCT over non-HSCT strategies.