Survival outcomes and treatment patterns in myelofibrosis in the JAK inhibitor era.
Key claim: In 1649 Spanish registry patients with myelofibrosis diagnosed from 2010 onward, median survival was 6.6 years and 5- and 10-year relative survival only 68% and 44% despite JAK inhibitors in about half of patients, with only 25% of transplant-eligible intermediate-2/high-risk patients transplanted and acute leukemia the leading cause of death.
Abstract
Data on real-world survival and treatment patterns in large, unselected myelofibrosis (MF) cohorts remain limited. We analysed 1649 patients with MF diagnosed from 2010 onwards and included in the Spanish Myelofibrosis Registry across 64 centres. Janus kinase (JAK) inhibitors were administered to approximately half of the patients. Among those aged ≤70 years with intermediate-2/high-risk International Prognostic Scoring System (IPSS), only 25% ultimately underwent transplantation. Median survival was 6.6 years, with no significant differences between primary and secondary MF; acute leukaemia was the most frequent cause of death, accounting for 20% of cases. Compared with a matched general population, relative survival at 5 and 10 years was 68% and 44% respectively. The reduction in relative survival was more pronounced in patients aged >65 years and in male patients, two subgroups that also exhibited a higher burden of comorbidities and a greater frequency of high molecular risk mutations. Remarkably, patients in the high-risk IPSS category had a 10-year relative survival of only 12%; however, survival reduction was not confined to high-risk disease, with divergence from expected survival emerging early among lower-risk categories. These findings highlight the persistent impact of MF on life expectancy in the contemporary JAK inhibitor era and the need for improvement in its overall management.
Why this matters
This is one of the largest contemporary real-world snapshots of what actually happens to MF patients in the JAK inhibitor era, and it shows that the decision layer is failing: three-quarters of transplant-eligible intermediate-2/high-risk patients are not transplanted, while acute leukemic transformation remains the leading killer. It reframes the area’s central question — ‘should I be transplanted, and when?’ — from a scoring-system optimization problem to a referral-execution problem, and provides a baseline against which risk-model refinements (MIPSS70, MTSS) must show they actually change practice.