Therapeutic approaches in myelofibrosis

Abstract

Introduction: Myeloproliferative neoplasm (MPN)-associated myelofibrosis is the most disabling of the classical Philadelphia-negative MPNs. The discovery that a gain-of-function mutation of JAK2 (JAK2V617F) is present in more than 60% of patients with MPN-associated myelofibrosis has provided a new target for innovative treatment strategies.

Areas covered: This review discusses the indications and limitations of conventional therapies employed for the treatment of MPN-associated myelofibrosis before reviewing the information available for new therapies, including the immunomodulatory and demethylating agents, histone deacethylase, mammalian target of rapamycin (mTOR) and JAK2- inhibitors. The Medline and ASH databases were searched for clinical trials on the medical therapy of MPN-associated myelofibrosis from early 2000 to December 2010.

Expert opinion: Three categories of drugs have proved to have significant activity in MPN-associated myelofibrosis. Up to a 40% response rate on anemia has been reported with the immunomodulator, pomalidomide. The m-TOR inhibitor RAD-001 and various JAK2 inhibitors have documented a profound effect on splenomegaly and constitutional symptoms, with some also having activity on anemia. These new drugs will give physicians more options to tailor therapeutic choice in this challenging disease.

Keywords::

• demethylating agents
• histone deacetylase inhibitors
• JAK2 inhibitors
• JAK2 V617F mutation
• mTOR inhibitors
• myelofibrosis
• myeloproliferative neoplasm
• response criteria

Notes

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