Prognostic markers in core-binding factor AML and improved survival with multiple consolidation cycles of intermediate-/high-dose cytarabine

Objectives: Core-binding factor acute myeloid leukaemia (CBF AML) defined by t(8;21)(q22;q22) or inv(16)(p13q22)/t(16;16)(p13;q22) has a favourable prognosis; however, 30%-40% of patients still relapse after chemotherapy. We sought to evaluate the risk factors for relapse in a de novo CBF AML cohort.

Patients/materials/methods: A retrospective review of patients from four Australian tertiary centres from 2001 to 2012, comprising 40 t(8;21) and 30 inv(16) AMLs.

Results: Multivariate analysis identified age (P = .032) and white cell count (WCC)>40 (P = .025) as significant predictors for inferior OS and relapse, respectively. Relapse risk was higher in the inv(16) group vs the t(8;21) group (57% vs 18%, HR 4.31, 95% CI: 1.78-10.42, P = .001). Induction therapy had no bearing on OS or relapse-free survival (RFS); however, consolidation treatment with >3 cycles of intermediate-/high-dose cytarabine improved OS (P = .035) and RFS (P = .063). Five patients demonstrated post-treatment stable q PCR positivity without relapse.

Conclusions: >3 consolidation cycles of intermediate-/high-dose cytarabine improves patient outcomes Age and inv(16) CBF AML subtype are predictors of inferior OS and RFS, respectively. Stable low-level MRD by qPCR does not predict relapse Similar OS in the inv(16) cohort compared to the t(8;21) cohort, despite a higher relapse rate, confirms salvageability of relapsed disease.