A Phase 2 Dose Regimen Optimization Study of Three Schedules of Voreloxin as Single Agent Therapy for Elderly Patients with Newly Diagnosed Acute Myeloid Leukemia

Abstract 1037 Poster Board I-59 Background: Voreloxin is a first-in-class anticancer quinolone derivative (AQD) that intercalates DNA and inhibits topoisomerase II, inducing apoptosis. Interim results of REVEAL-1, a Phase 2 (Ph 2) dose regimen optimization study of 3 schedules (sch) of single agent voreloxin in newly diagnosed elderly acute myeloid leukemia (AML) patients (pts), are reported. The initial dose regimen, voreloxin 72 mg/m2 qw x 3, was established in a Ph 1 dose-escalation study in relapsed/refractory leukemia pts (Lancet J et al., Proc ASH 2007). Overall remission rate (ORR = CR+CRp) was high (41%), but this regimen was less well tolerated in the frontline elderly population. The protocol explored 2 alternative voreloxin sch: 72 mg/m2 voreloxin qw x 2 and days 1 and 4 (d 1,4). A final cohort of pts is enrolling to the d 1,4 sch at 90 mg/m2. Dose escalation was based on safety data from the 72 mg/m2 cohort and from an ongoing Ph 1b/2 study of 90 mg/m2 voreloxin d 1,4 in combination with 1g/m2/d cytarabine x 5d (Lancet J, et al, ASCO 2009). Methods: Ph 2 study of 3 voreloxin sch (30 pts/sch): A 72 mg/m2 qw x 3 or B 72 mg/m2 qw x 2 or C 72 mg/m2 on d 1,4. C at 90 mg/m2 voreloxin is now enrolling to 20 pts. Eligibility: newly diagnosed AML (de novo or secondary AML), pts age ≥ 60 with ≥ 1 additional adverse risk factor (age ≥ 70, secondary AML, intermediate or unfavorable cytogenetics, or PS 2). PK were evaluated in a pt subset in cycle 1. Patient bone marrow aspirates (BMA) taken prior to dosing were tested ex vivo for extreme drug resistance (EDR®) to voreloxin. Results: To date, 105 pts have been treated. Preliminary safety and ORR are available for A, B and C at 72 mg/m2 voreloxin. Twelve pts in C at 90 mg/m2 are too early to evaluate (TETE). Overall incidence of infections and mucositis were reduced in B and C, sch with 2 voreloxin doses, relative to A which had 3 voreloxin doses. Voreloxin PK were similar to those in an earlier Ph 1 study in relapsed/refractory AML (Lancet J, et al., Proc ASH 2007). Pts whose BMA were inhibited < 48% by 1 μM voreloxin had a greater chance of treatment failure (p = 0.043) than those whose BMA were inhibited by ≥ 48%. Conclusions: In REVEAL-1, voreloxin demonstrates clinical activity with 3 dosing sch in previously untreated elderly (age ≥ 60) AML pts who are unlikely to benefit from standard chemotherapy. ORR across 3 sch was 35%; the majority (76%) were CR. Responses were seen in each risk factor category and with multiple risk factors. Of reinduced pts, 45% achieved CR(p). Durable remissions exceeding 6 months were observed in 50% (A) and 63% (B) thus far. C d 1,4 was selected for further development based on ORR (38%), 30 and 60 day all-cause mortality (7% and 14%, respectively) and an improved safety profile with lower rates of infection compared to previous schedules. Further accrual to C 90 mg/m2voreloxin d 1,4 is ongoing. Disclosures: Ravandi: Sunesis: sunesis study steering committee. Cripe:Sunesis: Research Funding. Chen:sunesis: Employment. Mahadocon:sunesis: Employment. Fox:Sunesis: Employment. Berman:Sunesis: Employment. Michelson:sunesis: Employment. Stuart:sunesis: sunesis study steering committee.