Pentostatin in hairy cell leukemia: Treatment by the special exception mechanism

An analysis of the clinical outcomes in 66 patients with hairy cell leukemia treated with pentostain under the Special Exception mechanism of the Division of Cancer Treatment, National Cancer Institute, between 1983 and 1987 has revealed a favorable balance of risk and benefit. Hematologic parameters and performance status were improved in most patients treated outside the clinical trials mechanism. The treating physicians considered 37 patients (56%) to be complete responders and 15 patients (23%) to be partial responders. Four patients (6%) died while receiving pentostatin. Life-threatening leukopenia (wbc count, <1,000/mm³) was reported in 24% of patients, and severe or life-threatening infection occurred in 11%. The experience gained with these patients supplements the information presently being collected from the controlled clinical trails and supports the development of a group C treatment protocol. [J Natl Cancer Inst 81:448-453, 1989]