Interferon-alpha in chronic myeloid leukemia revisited: a long-term retrospective study in Central and Northern Moravia.

Aims: We assessed the long-term outcome of consecutive patients in the chronic phase of chronic myeloid leukemia (CML) treated with interferon-alpha (INF-α) in Central and Northern Moravia between 1989 and 2006.
Methods: A retrospective study focused on the response, prognostic factors and side-effects of INF-α.
Results: 118 patients (67 males and 51 females, median age 50 years; range 18-71) were analyzed. The median follow-up was 82.6 months (12.4-212.6). Thirty-six patients (30.5%) achieved major cytogenetic response (CyR) in median of 18.3 months (3.7-47.3) and maintained it for a median of 64.0 months (7.0-176.0). Sixty-one patients treated with INF-α for more than 12 months had an overall survival (OS) of 137.0 months (95% CI 117.6-156.4). Eighteen (29.5%) achieved complete CyR (CCyR). 109 patients discontinued the treatment with INF-α because of hematologic or cytogenetic resistance in 53 (48.7%), progression of CML in 31 (28.4%) and intolerance to INF-α in 17 (15.6%) patients. The percentage of peripheral blasts, leukocyte count (>50x10(9)/L), splenomegaly, anemia (Hgb≤110 g/L) and Sokal score had statistical impact on the OS in univariate assessment but only the Sokal score remained significant in multivariate analysis. Additional cytogenetic abnormalities at diagnosis were associated with poor prognosis.
Conclusions: In most patients, treatment with INF-α had to be stopped because of a failure to induce response, progression of CML or side-effects but nearly one third of patients treated at least for one year had a long-term benefit from INF-α. The best prognosis was associated with achievement of CCyR and negativity of BCR-ABL in nested RT-PCR.