α chromosome-positive chronic myeloid leukemia after failure of interferon- Result of high-dose imatinib mesylate in patients with Philadelphia

Imatinib (Gleevec) at 400 mg daily is effective in chronic phase CML post interferon failure, although only a few patients achieve a molecular remission. We investigated whether higher doses of imatinib may be more effective. Thirty-six patients with chronic phase CML failure to interferon were treated with imatinib 400 mg twice daily. Median time from diagnosis was 25 months (range, 10 to 135); 4 patients (11%) had clonal evolution. All 11 patients with active disease achieved complete hematologic response. Excluding patients with <35% Phpositive metaphases before the start of therapy, 19/21 (90%) evaluable patients achieved a major cytogenetic response. Twenty-four of 27 (89%) evaluable patients achieved a complete cytogenetic response. Quantitative PCR was performed in bone marrow every 3 months. Eighteen of 32 evaluable patients (56%) showed BCR-ABL/ABL percentage ratios <0.045%, including 13 (41%) with undetectable levels. With a median follow-up of 15 months, all patients were alive in chronic phase. Toxicities were similar to those reported with standard dose; 71% of patients continue to receive ≥600 mg of imatinib daily. In conclusion, high-dose imatinib induces complete cytogenetic responses in most patients with chronic phase CML post interferon failure. This is accompanied by a high rate of molecular remission. For personal use only. by guest on June 1, 2013. bloodjournal.hematologylibrary.org From