Human recombinant interferon-alpha-2 in the treatment of patients with hairy cell leukemia.

During the last 2 years, we have treated 14 hairy cell leukemia (HCL) patients with human recombinant interferon-2 alpha (Boehringer Ingelheim). The above group consisted of eight nonsplenectomized and six previously splenectomized progressive HCL patients. The patients received daily doses of 5 x 10(6) units of IFN for 3 months and two doses per week for the next 3 months thereafter by i.m. route. The therapy resulted in the complete (nine cases, = 64.3%) or partial (two cases = 14.3%) clinical and hematological remission (response rate 78.6%), with either disappearance or marked reduction in circulating and bone marrow hairy cells, decreased spleen size, and recovery of normal hemopoiesis. Apart from a transient flulike syndrome during the first 2 weeks of therapy, no other side effects were observed.