Addition of AEG35156 XIAP antisense oligonucleotide in reinduction chemotherapy does not improve remission rates in patients with primary refractory acute myeloid leukemia in a randomized phase II study.

Background: XIAP (X-linked inhibitor of apoptosis protein) is an inhibitor of caspases 3 and 9 that is overexpressed in acute myeloid leukemia (AML) and may contribute to chemoresistance. We report an open-label randomized phase II trial of reinduction chemotherapy with and without the XIAP antisense oligonucleotide AEG35156 in patients with AML who did not achieve remission with initial induction chemotherapy.

Methods: Twenty-seven patients with AML who were refractory to initial induction chemotherapy were randomized and treated with AEG35156 (650 mg) in combination with high-dose cytarabine and idarubicin. Thirteen patients were randomized and treated with high-dose cytarabine and idarubicin alone. The rates of response and toxicity were determined.

Results: Of the 27 patients assigned to AEG35156 in combination with high-dose cytarabine and idarubicin, 3 died during reinduction chemotherapy, 5 achieved complete remission (CR), and 6 achieved CR with incomplete platelet count recovery (CRp), for an overall response rate of 41%. Of the 13 patients assigned to the control arm of the study, none died during reinduction, 6 achieved CR, and 3 achieved CRp, for an overall response rate of 69%. The differences in response rates between patients in the AEG35156 and control arms were not statistically different (P = 0.18 by the χ(2) test).

Conclusions: The addition of AEG35156 to reinduction chemotherapy was well tolerated but did not improve rates of remission. Therefore alternative therapeutic strategies should be explored in patients with AML refractory to induction chemotherapy.