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Refractory/early relapsed (Ref/eRel) acute myeloid leukemia (AML) in patients ≥60 years old is the most important unmet medical need in the salvage setting, where outcomes are exceptionally poor and no standard of care exists.[1][1] Vosaroxin is a first-in-class anticancer quinolone derivative

Vosaroxin is an anti-cancer quinolone-derived DNA topoisomerase II inhibitor. We investigated vosaroxin with decitabine in patients ≥60 years of age with newly diagnosed acute myeloid leukemia (n=58) or myelodysplastic syndrome (≥10% blasts) (n=7) in a phase II non-randomized trial. The initial 22 patients received vosaroxin 90 mg/m2 on days 1 and 4 with decitabine 20 mg/m2 on days 1-5 every 4-6 weeks for up to seven cycles. Due to a high incidence of mucositis the subsequent 43 patients were given vosaroxin 70 mg/m2 on days 1 and 4. These 65 patients, with a median age of 69 years (range, 60-78), some of whom with secondary leukemia (22%), adverse karyotype (35%), or TP53 mutation (20%), are evaluable. The overall response rate was 74% including complete remission in 31 (48%), complete remission with incomplete platelet recovery in 11 (17%), and complete remission with incomplete count recovery in six (9%). The median number of cycles to response was one (range, 1-4). Grade 3/4 mucositis was noted in 17% of all patients. The 70 mg/m2 induction dose of vosaroxin was associated with similar rates of overall response (74% versus 73%) and complete remission (51% versus 41%, P=0.44), reduced incidence of mucositis (30% versus 59%, P=0.02), reduced 8-week mortality (9% versus 23%; P=0.14), and improved median overall survival (14.6 months versus 5.5 months, P=0.007). Minimal residual disease-negative status by multiparametric flow-cytometry at response (± 3 months) was achieved in 21 of 39 (54%) evaluable responders and was associated with better median overall survival (34.0 months versus 8.3 months, P=0.023). In conclusion, the combination of vosaroxin with decitabine is effective and well tolerated at a dose of 70 mg/m2 and warrants randomized prospective evaluation. ClinicalTrials.gov: NCT01893320.

Vosaroxin is a first-in-class anticancer quinolone derivative that intercalates DNA and inhibits topoisomerase II. This study assessed the safety and tolerability of vosaroxin plus cytarabine in patients with relapsed/refractory acute myeloid leukemia. Escalating vosaroxin doses (10-minute infusion; 10-90 mg/m(2); days 1, 4) were given in combination with cytarabine on one of two schedules: schedule A (24-hour continuous intravenous infusion, 400 mg/m(2)/day, days 1-5) or schedule B (2-hour intravenous infusion, 1 g/m(2)/day, days 1-5). Following dose escalation, enrollment was expanded at the maximum tolerated dose. Of 110 patients enrolled, 108 received treatment. The maximum tolerated dose of vosaroxin was 80 mg/m(2) for schedule A (dose-limiting toxicities: grade 3 bowel obstruction and stomatitis) and was not reached for schedule B (recommended phase 2 dose: 90 mg/m(2)). In the efficacy population (all patients in first relapse or with primary refractory disease treated with vosaroxin 80-90 mg/m(2); n=69), the complete remission rate was 25% and the complete remission/complete remission with incomplete blood count recovery rate was 28%. The 30-day all-cause mortality rate was 2.5% among all patients treated at a dose of 80-90 mg/m(2). Based upon these results, a phase 3 trial of vosaroxin plus cytarabine was initiated in patients with relapsed/refractory acute myeloid leukemia. (Clinicaltrials.gov identifier: NCT00541866).