Predictive parameters for imatinib failure in patients with chronic myeloid leukemia.

Objective: Until recently, imatinib was the standard first-line treatment in chronic myeloid leukemia (CML). The inclusion of nilotinib and dasatinib as first-line options in CML raised a debate on treatment selection. The aim of our study was to analyze predictive parameters for imatinib response as the first-line treatment of CML patients.

Methods: The study included 168 consecutive patients with chronic phase Philadelphia-positive CML who were diagnosed and treated with Imatinib 400 mg once daily at a single university hospital. Numerous parameters were analyzed in terms of imatinib response including comorbidities as well as occurrence of second malignancies.

Results: After the median follow-up of 87 months in 61 patients (36.3%), the imatinib failure was verified. Cox regression analysis identified hepatomegaly (p = 0.001), leukocytosis ≥ 100 × 109/l (p = 0.001), blood blasts ≥ 1% (p = 0.002), and the presence of additional cytogenetic aberrations (p = 0.002) as predictors of Imatinib failure. Based on these findings, a new prognostic model was developed according to which imatinib failure had 17% (8/47) of patients in low risk, 34.9% (30/86) of patients in intermediate risk, and 76.7% (23/30) of patients in high-risk group (HR = 3.973, 95% CI for HR 2.237-7.053, p < 0.001).

Conclusion: The new score allows better selection of patients who are suitable for treatment with imatinib and may guideline the clinical decision for front-line treatment of CML.