Repetitive cycles of high-dose cytarabine benefit patients with acute myeloid leukemia and inv(16)(p13q22) or t(16;16)(p13;q22): results from CALGB 8461.

PURPOSE: To study the impact of repetitive (three to four courses) versus a single course of high-dose cytarabine (HDAC) consolidation therapy on outcome of patients with acute myeloid leukemia (AML) and inv(16)(p13q22) or t(16;16)(p13;q22).

PATIENTS AND METHODS: We examined the cumulative incidence of relapse (CIR), relapse-free survival (RFS), and overall survival (OS) for 48 adults younger than 60 years with inv(16)/t(16;16) who had attained a complete remission on one of four consecutive clinical trials and were assigned to receive HDAC consolidation therapy. Twenty-eight patients were assigned to either three or four courses of HDAC, and 20 patients were assigned to one course of HDAC followed by alternative intensive consolidation therapy.

RESULTS: Pretreatment features were similar for the two groups. The CIR was significantly decreased in patients assigned to receive three to four cycles of HDAC compared with patients assigned to one course (P=.03; 5-year CIR, 43% v 70%, respectively). The difference in RFS also approached statistical significance (P=.06). In a multivariable analysis that adjusted for potential confounding covariates, only treatment assignment (three to four cycles of HDAC) predicted for superior RFS (P=.02). The OS of both groups was similar (P=.93; 5-year OS, 75% for the three to four cycles of HDAC group v 70% for the one cycle of HDAC group), reflecting a high success rate with stem-cell transplantation salvage treatment administered among patients in both treatment groups.

CONCLUSION: We conclude that, in AML patients with inv(16)/t(16;16), repetitive HDAC therapy decreases the likelihood of relapse compared with consolidation regimens including less HDAC.