Treating early-stage myelofibrosis.

Myelofibrosis (MF) is a Philadelphia chromosome-negative myeloproliferative neoplasm associated with bone marrow fibrosis, splenomegaly, a high symptom burden, and poor prognosis. Treatment is based on a risk-adapted approach, with treatment guidelines generally recommending allogeneic stem cell transplant or drug-based therapy for patients with higher-risk or more advanced disease and recommending observation or the "watch-and-wait" strategy for those with lower-risk or early-stage MF. With the advent of targeted therapies, such as the Janus kinase inhibitors, many patients have experienced substantial clinical benefits, including reduction in splenomegaly and symptoms and, in some instances, improvement or stabilization of bone marrow fibrosis and reduction of JAK2 V617F allele burden. These observations raise the possibility of patients in earlier phases of the disease also benefiting from treatment with targeted therapies. In this review, we discuss the current treatment options for patients with early-stage MF and the available evidence supporting the treatment of patients with less-advanced disease. Overall, therapies used to treat patients with early-stage MF will have to be assessed in randomized studies, with the potential benefits balanced against adverse events associated with treatment.