Effect of adding gemtuzumab ozogamicin to induction chemotherapy for newly diagnosed acute myeloid leukemia: a meta-analysis of prospective randomized phase III trials

Abstract

Gemtuzumab ozogamicin (GO) is a targeted antineoplastic agent comprised of a recombinant anti-CD33 humanized antibody linked to calicheamicin. Previous trials have showed conflicting results concerning the efficacy and toxicity of adding GO to induction chemotherapy for newly diagnosed acute myeloid leukemia (AML). A systematic review and meta-analysis was conducted to resolve this controversial issue. Summary data from five randomized phase III trials compared adding GO to induction chemotherapy with induction chemotherapy alone for newly diagnosed AML were meta-analyzed. Pooled hazard ratios (HRs) and 95% confidence intervals (CIs) for overall survival (OS) and relapse-free survival (RFS), and pooled odds ratios (ORs) and 95% CIs for complete remission (CR) rate, incidences of resistance disease, relapse and toxicity were calculated. Data of 3596 patients (1798 GO and 1798 controls) from five randomized phase III trials were analyzed. Compared with induction chemotherapy alone, adding GO significantly prolonged OS (HR 0.93, 95% CI 0.86-1.00, P=0.05) and RFS (HR 0.87, 95% CI 0.79-0.95, P=0.003), decreased the incidences of resistant disease (OR 0.71, 95% CI 0.55-0.93, P=0.01) and relapse (OR 0.75, 95% CI 0.63-0.90, P=0.002), but had no effect on CR rate (OR 1.15, 95% CI 0.91-1.46, P=0.24). Sensitivity analysis yielded similar results. Subgroup analysis identified that cytogenetics might be an influencing factor for the effect of adding GO. In addition, the risks of grade 3-4 nausea/vomiting, diarrhea and liver aspartate transaminase (AST) elevation were increased in GO arm. Adding GO to induction chemotherapy for newly diagnosed AML can significantly prolong OS and RFS, decrease incidences of resistant disease and relapse, but may increase risks of grade 3-4 nausea/vomiting, diarrhea and liver AST elevation.