Orphan drugs for myelofibrosis

Abstract

Introduction: Myelofibrosis (MF), classified as a myeloproliferative neoplasm (MPN) by the WHO, is an orphan disorder in which therapeutic strategies have been slow to develop, likely due to a lack of understanding of the disease pathogenesis.

Areas covered: In this article, progress dating from the seminal descriptions of a highly prevalent mutation in the JAK2 gene, JAK2 V617F in 2005 is reviewed. This article describes, in brief, the current status of our scientific understanding in this field and reflects on how this is now stimulating a change in therapeutic strategies for patients. Information was gathered from a review of the medical literature and conference abstracts, in particular the most recent American Society of Haematology meeting. Each novel therapy is described, in turn, and then future strategies for evaluating this plethora of potential agents are discussed. Concerns are highlighted regarding the difficulty in comparing some data and the lack of a clear surrogate marker such as BCR/ABL transcript levels as used in cell-mediated lympholysis.

Expert opinion: Overall, for the field of MF and MPNs as a whole, this is a time of unprecedented interest, activity, and a very real opportunity to make significant inroads into this difficult disorder. The approval of ruxolitinib demonstrates already the great potential for benefit in this field. However, economic constraint also impinges upon its reimbursement and collection of proper data with regard to both disease burden and health benefit is necessary to ensure patient access after clinical efficacy and safety approval.

Keywords::

• histone deacetylase
• JAK inhibitor
• myelofibrosis
• novel therapies

Notes

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