Treatment of lymphoid neoplasias with interferon. II. Human leucocyte alpha-interferon in chronic lymphatic leukemia (CLL). PHase I-II trial.

Nine patients with chronic lymphoid leukemia (CLL) were treated with subcutaneous human (leukocyte) interferon a (IF a). In the first part of the study, 7 patients received intermittent 10 day courses, with free intervals of 10 to 15 days and with dose escalation in the same patient from cycle to cycle from 1.5 to 6 X 10(6) units daily, if tolerated. As we observed a decrease of peripheral lymphocytosis with low doses, and as high doses gave more side-effect in the second part of the study, 4 patients (including two who has previously received intermittent courses) were treated for three months or more at a dose of 1.5 X 10 units daily. Tumor mass reduction was seen in only three patients. However, a significant decrease in peripheral lymphocytosis was seen in 7 patients who were sustained in the continuous treatment group; with relapse at treatment discontinuation in one patient and despite continuation in another. Immune monitoring with currently available T, B, NK and macrophage tests, showed a good correlation between NK cell activity and clinical response, in this group of patients. Further studies are warranted to determine the best modalities of treatment, the population of patients likely to benefit from such treatment, the possible special respective indications of IF, and also the other treatments of CLL. One can already consider as a reasonable indication CLL presentations with myeloid insufficiency as IF is not myelotoxic, contrary to chemotherapy.