Fludarabine therapy in hairy cell leukemia.
 This study evaluated the efficacy of fludarabine, a new adenine nucleoside analogue, in typical and variant forms of hairy cell leukemia (HCL).
 Two patients with HCL and one patient with a variant form of HCL (HCL-variant) with resistant or progressive disease with prior treatments were studied.
 Fludarabine (30 mg/m2) was administered intravenously over 30 minutes daily for 5 days every month.
 Two patients (one with HCL and one with HCL-variant) achieved partial responses; the third patient had a minor response.
 This is the first report of encouraging activity of fludarabine in typical and variant forms of HCL.
 Further experience with fludarabine in these disorders is indicated.
