Results of Interferon-Alpha Therapy in Patients With Chronic Myelogenous Leukemia 60 Years of Age and Older Jorge Cortes, MD, Hagop Kantarjian, MD, Susan O’Brien, MD, L.E. Robertson, MD, Sherry Pierce, RN, Moshe Talpaz, MD, Houston, Texas PURPOSE: To determine the response rate to interferon-alpha (IFN-CX) 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-(11 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-a 5x 106 U/m* 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-a 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-a-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 IFNw 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-a therapy, but experience more toxicity. This therapy should be considered for these patients if they are otherwise in good condition, with careful attention to IFNw toxicity and its management. From the Department of Hematology (JC, HK, SO, LER, SP) and Section of Biologic Studres (MT), University of Texas, M.D. Anderson Cancer Center, Houston, Texas. Requests for reprrnts should be addressed to Hagop Kantarjian, MD, Department of Hematology, M.D. Anderson Cancer Center, 1515 Holcombe Boulevard Box 61, Houston, Texas 77030. Manuscript submitted March 2, 1995 and accepted in rewed form December 13, 1995. C hronic myelogenous leukemia (CML) is a clonal myeloproliferative disorder characterized by the presence of a translocation t(9;2f!)(q34;qll) known as the Philadelphia chromosome (Ph).‘J It has a biphasic or triphasic course with a chronic phase that lasts a median of 5 to 7 years in recent tri- als. It eventually progresses to a blastic phase, which is almost inevitably fatal.’ This may be preceded by an accelerated phase. Although treatment with con- ventional chemotherapy such as busulfan and hy- droxyurea can control the hematologic manifesta- tions of the disease, Ph-positive clonal leukemic cells still predominate, and the final outcome is mostly un- affected.” To date, only two approaches have proven effective in producing long-lasting suppression of the Ph-positive cells, resulting in prolonged survival: al- logeneic bone marrow transplantation (BMT)“-7 and interferon alpha (IFN-a).8vQ Approximately loo/oto 20% of all patients with CML are 60 years of age and older. l,l” Most series using BMT limit this treatment option to patients younger than 55 to 60 years of age. 6,Ti Therefore, one potentially useful alternative for these patients at present is IFN-cx ther- apy. In the general population, the rate of complete hematologic remissions is 70% to SO%, and major cy- togenetic remissions are achieved in 20% to 35%.‘a There is little information on the response rate and tolerance to IFN-a in patients aged 60 years and older. The purpose of this analysis was to investigate whether patients aged 60 years and older respond to IFN-a with a similar rate as do younger patients, and to analyze the side effects of IFN-cr therapy in this age group. PATIENTS AND METHODS From 1982 to 1990, 274 consecutive patients with CML in the early chronic phase (ie, <l year from di- agnosis) were treated at M.D. Anderson Cancer Center with IFN-a as their primary therapy. Thirty-five of these patients (13%) were 60 years of age or older at the time of the initiation of therapy and constitute the basis for this report. Informed consent was obtained from all patients according to institutional guidelines. Treatment Protocols Patients were enrolled in different protocols with IFN-a. Eight of the 35 patients were treated with hu- man leukocyte IFN-a; 14 patients received recombi- nant human IFN-a alone (n = 11) or with recombinant 452 April 1996 The American Journal of Medicind Volume 100