Clinical features and outcomes of V617F-positive polycythemia vera and essential thrombocythemia according to the V617F allele burden.

BACKGROUND

mutation status is a well-known risk factor for thrombosis in patients with myeloproliferative neoplasms. However, the clinical usefulness of V617F allele burden is under investigation.

METHODS

We retrospectively evaluated the impact of the V617F allele burden on clinical characteristics and outcomes of V617F-positive polycythemia vera (PV) and essential thrombocythemia (ET). The V617F allele burden was measured using sequencing.

RESULTS

Altogether, 127 patients with V617F mutation (PV, N=61; ET, N=66) were included in this study. V617F allele burdens were positively correlated with white blood cell counts, hemoglobin values, lactate dehydrogenase levels, and platelet counts. The median values of V617F allele burden in patients with PV and ET were 58% and 30%, respectively. A V617F allele burden of ≥30%, older age, and a higher hemoglobin level were risk factors for thrombotic events in ET. In patients with PV, older age was the only thrombotic risk factor. The 8-year probabilities of overall survival (OS) were 82.9% in all patients. A high V617F allele burden (≥58%) was associated with poor OS in patients with PV. For the patients with ET, the difference in 8-year OS based on the V617F allele burden was not significant.

CONCLUSION

The V617F allele burden was correlated with hematologic parameters and clinical outcomes. Assessing the V617F allele burden can be helpful in predicting the thrombotic risk and disease course in patients with V617F-positive PV and ET.