High-dose imatinib for newly diagnosed chronic phase chronic myeloid leukemia patients-Systematic review and meta-analysis

Imatinib at a dose of 400 mg daily is considered frontline treatment in chronic phase chronic myeloid leukemia (CP-CML). We conducted a systematic review and meta-analysis of randomized controlled trials comparing frontline treatment with imatinib 400 mg daily versus higher doses (≥600 mg daily) in patients with CP-CML. The search yielded four trials, randomizing 1,673 patients. At 12 months, high dose compared with standard dose imatinib improved complete cytogenetic response (CCyR) (RR 1.17, 95% CI 1.08-1.26, four trials, I² = 33%) as well as major molecular response (MMolR) (RR 1.26, 95% CI 1.12-1.42, four trials, I² = 0%). There was no difference in all-cause mortality or disease progression at the end of follow up. Adverse events requiring discontinuation were more common in the high-dose arm (RR 1.98, 95% CI 1.20-3.26, three trials, I² = 0%), as were Grade III/IV neutropenia and thrombocytopenia: RR 1.56, 95% CI 1.15-2.12 and RR 1.86, 95% CI 1.28-2.70, respectively. There is currently insufficient evidence to support the routine use of higher doses of imatinib as frontline treatment for CP-CML. Extended follow up is needed to evaluate if the superior CCyR and MMolR with higher doses of imatinib will translate to long-term clinical benefit.