Treatment of systemic mast cell disease with 2-chlorodeoxyadenosine.

We used three to six courses of 2-chlorodeoxyadenosine (2-CdA) (2-h infusion at 0.14 mg/kg per day x 5 days) given over a period of 3-36 months to treat four patients with aggressive systemic mast cell disease (SMCD) that was resistant to interferon-alpha (IFN-alpha). Treatment with 2-CdA resulted in a major response in two patients and a good partial response in one other patient (75% overall response). Treatment was well tolerated and duration of remission in responding patients ranges from 2 months to 4+ years since the completion of treatment with 2-CdA.