Stage I findings of a two-stage phase II study to assess the efficacy, safety, and tolerability of barasertib (AZD1152) compared with low-dose cytosine arabinoside (LDAC) in elderly patients (pts) with acute myeloid leukemia (AML).

6527 Background: Barasertib is the pro-drug to barasertib-hQPA, a selective Aurora B kinase inhibitor with preliminary anti-AML activity in a Phase I/II study (Lowenberg et al. Blood 2011;118:6030). Methods: AML pts aged ≥60 y considered unsuitable for intensive chemotherapy were randomized 2:1 to open-label barasertib 1200 mg (7-day iv infusion) or LDAC 20 mg (sc twice daily for 10 days) in 28-day cycles (NCT00952588). The primary endpoint was improved objective complete response rate (OCRR: CR + CRi [Cheson criteria, but requiring CRi confirmation ≥21 days after first appearance, with partial recovery of platelets and neutrophils]). Secondary endpoints included duration of response (DoR), overall survival (OS) and safety. Results: 74 pts (barasertib, 48; LDAC, 26) received treatment and all completed ≥1 cycle. A significant improvement in OCRR was observed with barasertib (35.4% [17/48] vs 11.5% [3/26]; difference, 23.9% [95% CI, 2.7-39.9]; P<0.05); barasertib responses were seen in all cytogenetic risk...