Results of interferon-alpha therapy in patients with chronic myelogenous leukemia 60 years of age and older

PURPOSE: TO determine the response rate to interferon-alpha (IFN-alpha) in patients with chronic myelogenous leukemia (CML) aged 60 years and older. PATIENTS AND METHODS: Patients with CML aged 60 years and older included in all protocols with IFN-alpha therapy for early chronic phase CML at the M.D. Anderson Cancer Center were analyzed. They were treated with human leukocyte or recombinant human IFN-alpha 5x10(6) U/m(2) daily alone or in combination with hydroxyurea or IFN gamma. The clinical characteristics of the patients were analyzed and their hematologic and cytogenetic responses to IFN-alpha and survival from the initiation of therapy were determined. Results were compared with those of younger patients treated in the same protocols. Treatment-related toxicity was also analyzed. RESULTS: Thirty-five of 274 (13%) patients included in trials of IFN-alpha-based regimens for CML were 60 years and older. Older patients had a higher percentage of bone marrow blasts (P = 0.04) and basophils (P = 0.09) than younger patients. Sixty-nine percent achieved a complete hematologic remission with IFN-alpha therapy, and 51% had a cytogenetic response, which was major in 26% and complete (Philadelphia chromosome-positive cells = 0%) in 20%. Their median survival was 64 months, and the estimated 5-year survival rate was 62%. These results were not different from those in younger patients. Twenty-two patients (63%) had at least grade 2 toxicity requiring dose adjustment. The most frequent side effects were neurotoxicity in 31% and chronic fatigue in 29%. CONCLUSIONS: Patients with CML 60 years of age and older respond well to IFN-alpha therapy, but experience more toxicity. This therapy should be considered for these patients if they are otherwise in good condition, with careful attention to IFN-alpha toxicity and its management.