A phase II study alternating alpha‐2a‐interferon and gamma‐interferon therapy in patients with chronic myelogenous leukemia

Patients with Philadelphia chromosome‐positive chronic myelogenous leukemia (CML) were treated with a combination of alpha‐interferon and gamma‐interferon. Recombinant alpha‐2a‐interferon (Roferon‐A, Hoffmann‐LaRoche, Inc., Nutley, NJ) and recombinant gamma‐interferon (Genentech, Inc., South San Francisco, CA) were administered on alternating weeks each at doses ranging from 2 to 10 MU/m² given intramuscularly. Of the 27 patients, 11 (41%) achieved complete hematologic remission (CHR) and 3 (11%) achieved partial hematologic remission (PHR). Responses were seen among 9 of 22 (41%) patients treated during the chronic phase of the disease and in 2 of 5 (40%) patients treated during the accelerated phase/second chronic phase. Cytogenetic responses were seen in six patients, including one complete response and five minor responses. Toxicities included flu‐like symptoms, which appeared to be more severe with gamma‐interferon than with alpha‐interferon, hypertriglyceridemia, and thrombocytopenia. In this limited study, an improved outcome was not observed for the combination regimen compared with alpha‐interferon alone. Cancer 68:2125–2130.