INTERFERON-ALPHA IS AN ACTIVE THERAPEUTIC AGENT IN CHRONIC MYELOGENOUS LEUKEMIA

Clinical trials of natural interferon-alpha in the treatment of Philadelphia chromosome (Ph1) positive chronic myelogenous leukemia (CML) were carried out in a cooperative study of 22 institutions in Japan. Patients with CML, in the chronic or accelerated phase, were given intramuscular or subcutaneous injections of human lymphoblastoid interferon (HLBI) at the doses of 6x10(6) units/body daily. Forty-one out of the 47 patients enlisted in this study between Jan. 1987 and Jan. 1988 were evaluated for clinical effects. Among 30 of these evaluated patients who were in the chronic phase, 15 (50%) achieved complete hematological remission (CHR) and 14 partial hematological remission (PHR). The response rate (CHR+PHR) was 97% (29/30). Among 11 patients in the accelerated phase, 4 (36%) achieved CHR and 2 PHR. The response rate in the accelerated phase was 55% (6/11). In all 41 patients evaluated, the over all response rate was 85% (35/41). In 13 of 29 responding patients treated for more than 6 months, cytogenetic investigation showed a decline in Ph1 positive bone marrow cells from 100% to 92-0% (median 45%). Complete cytogenetic response (CCR) was observed in 3 cases. They were all in the early chronic phase within 1 year following diagnosis, and had no previous therapy and no splenomegaly. Adverse effects such as fever, general fatigue and liver dysfunction were usually mild and transient. These results indicate IFN-alpha can be a useful therapeutic agent for CML, especially in the early chronic phase.