Myeloproliferative neoplasms

Abstract

Myeloproliferative neoplasms (MPNs), polycythaemia vera, essential thrombocythaemia and myelofibrosis – are uncommon clonal haematological malignancies generally diagnosed from late middle age onwards, although they can occur in children and young adults. They should be suspected in patients with elevated blood counts, atypical thrombosis or splenomegaly. Their clinical courses share similarities, including thrombosis, haemorrhage and a tendency to progress to myelofibrosis or acute myeloid leukaemia. Myelofibrosis has a poorer prognosis and significant disease burden affecting quality of life. Advances in diagnostics and genomics have recently been used to stratify risk more accurately. Furthermore, the development of treatment modalities aimed at targeting specific molecular pathways, such as Janus kinase inhibitors, has resulted in a therapeutic paradigm shift. Several ground-breaking studies have proved the efficacy of the first such agents and they are now licensed as first-line therapy in myelofibrosis and as second line in polycythaemia vera. Additional targets, such as CALR, are under evaluation in clinical trials. However, the mainstay of treatment for polycythaemia vera and essential thrombocythaemia remains aggressive management of thrombotic risk factors, antiplatelet therapy for most patients, and cytoreductive agents such as hydroxycarbamide and interferon for patients at high risk of thrombosis. This is, nevertheless, a rapidly evolving landscape.