Treatment of adult systemic mastocytosis with interferon-alpha: results of a multicentre phase II trial on 20 patients.

Systemic mastocytosis (SM) is characterized by proliferation of mast cells in various organs, which may release a wide variety of mediators, thereby explaining the broad clinical spectrum of disease manifestations. The potentially life-threatening systemic symptoms and tumoral proliferation are poorly controlled despite the use of several cytotoxic chemotherapies and/or symptomatic treatments. Twenty consecutive adult SM patients with histologically confirmed bone marrow (BM) involvement received interferon-alpha subcutaneously (1-5 million units/m2/d, with progressive dose intensification over the first month of treatment) and were evaluated after 6 months of therapy.