Imatinib Compared with Imatinib/Cytarabine for the First-Line Treatment of Early Philadelphia Chromosome–Positive Chronic Myeloid Leukemia: Results of a Randomized Clinical Trial of the Mexican Collaborative Leukemia Group

Background

In an attempt to improve the cytogenetic and molecular response rate in Philadelphia chromosome–positive early chronic-phase CML, we compared the combination of imatinib plus low-dose cytarabine (Ara-C) versus imatinib alone.

Patients and Methods

After a follow-up of 4 years, we included 112 patients in a randomized allocation to receive imatinib 400 mg alone orally every day (group A, 81 patients) versus imatinib in the same schedule plus Ara-C 10 mg/m² per day by subcutaneous injection daily every 10 days each month (group B, 31 patients). Both treatment groups were comparable according to hematologic basal parameters, age, sex, and previous treatment.

Results

Complete hematologic response was achieved in > 90% of patients in both groups; however, a shorter time and a higher complete cytogenetic response rate was documented in patients in group B compared with patients treated with imatinib alone (48.5% vs. 34%). Although a higher relapse-free survival (RFS) was documented in group B, no difference was observed in overall survival (OS) in both groups.

Conclusion

Our results show that the addition of Ara-C in the treatment of patients with chronic-phase CML clearly improved the cytogenetic response rate and the RFS, but new modalities of treatment need to be evaluated after relapse because the OS rate was similar in both groups. Of interest is that there was more progression in group A than in group B (16 cases vs. 1 case). This modality of therapy needs to be compared with new emerging options of first-line treatment in this disease.