The role of interferon-α in the treatment of idiopathic myelofibrosis

Idiopathic myelofibrosis (IMF) is se chronic myeloproliferative disorder characterized by fibrosis of the bone marrow, varying degrees of extramedullary hematopoiesis, splenomegaly, anemia, and a leukoerythroblastic peripheral blood smear. Bone marrow fibrosis develops as a secondary phenomenon and is caused by increased intramedullary activity of mitogens such as platelet-derived growth factor (PDGF), transforming growth factor-beta (TGF-beta), basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), and calmodulin. Because, of the variable clinical course of IMF, attempts have been made to define prognostic parameters that can be helpful in detecting patients with a shortened life expectancy. The most important adverse prognostic parameters that have been reported are hemoglobin concentration, age, leukocyte count, number of thrombocytes, and cytogenetic abnormalities. However, no standardized prognostic score for IMF has yet been established. Therapeutic strategies in IMF remain predominantly supportive. The most common are blood transfusions, androgens, and cytoreductive agents such as hydroxyurea. Bone marrow transplantation is increasingly being taken into consideration, but it still has to be regarded as an experimental approach. Interferon-alpha (IFN-alpha) has shown promising results in early hyperproliferative stages of IMF but has no or only very little effect in more advanced stages of the disease. Whether IFN-alpha is able to postpone marrow fibrosis if administered in early disease stages remains to be determined in future clinical trials.