ROLE OF HUMAN-LEUKOCYTE INTERFERON-ALPHA IN THE TREATMENT OF PATIENTSWITH POLYCYTHEMIA-VERA

Eighteen patients with polycythemia vera who were less than 60 years o ld received human leukocyte interferon-alpha subcutaneously at a start ing dose of 3 MU three times a week. The interferon dose was escalated to 6 MU three times a week if it was well tolerated and disease was n ot controlled after 3 months of treatment at the lower dose. Hematolog ic response was defined as complete if the hematocrit was maintained a t less than 45% in the absence of phlebotomy and partial if the hemato crit was kept at 45% to 50%, associated with a 50% or greater reductio n of phlebotomy requirements; no response was defined as a response le ss than a partial response. Complete disease control was achieved in 1 1 patients, with partial control in a further six cases. One patient f ailed to respond. Median duration of response was 16 months (range 5 t o 43 months), with 15 patients still under treatment. Therapy with hum an leukocyte interferon-alpha significantly improved (p < .01) phlebot omy requirements, the degree of splenomegaly, pruritus scores, iron st ores and mean red cell volume values, and platelet and leukocyte count s. Interferon treatment did not produce remarkable side effects and no patient withdrew from the study because of intolerance. We conclude t hat subcutaneous human leukocyte interferon-alpha is an effective and well-tolerated therapy in the management of polycythemia vera-associat ed myeloproliferation and pruritus in patients less than 60 years old.