The addition of vosaroxin to cytarabine might be of clinical benefit to some patients with relapsed or refractory acute myeloid leukemia (AML), a new study published online ahead of print in the journal The Lancet Oncology has shown.

For the phase 3 trial, researchers sought to assess the safety and efficacy of vosaroxin plus cytarabine in patients with relapsed or refractory AML. Vosaroxin is a first-in-class anticancer quinolone derivative and topoisomerase II inhibitor.

Researchers enrolled 711 patients with AML who had refractory disease or were in first relapse after one or two cycles of previous induction chemotherapy, including at least one cycle of cytarabine plus an anthracycline. 

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Participants were randomly assigned 1:1 to receive cytarabine 1 g/m2 IV on days 1-5 in combination with vosaroxin 90 mg/m2 IV on days 1 and 4 in the first cycle and 70 mg/m2 in subsequent cycles or placebo.

Results showed that median overall survival was 7.5 months (95% CI: 6.4, 8.5) in the vosaroxin arm and 6.1 months (95% CI: 5.2, 7.1) in the placebo arm (HR = 0.87; 95% CI: 0.73, 1.02; P=0.024).

Researchers found that 30% of patients in the vosaroxin group achieved a complete remission compared with 16% of those in the placebo group (P<0.0001).

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In regard to safety, grade 3 or higher febrile neutropenia, neutropenia, stomatitis, hypokalemia, bacteremia, sepsis, and pneumonia occurred more frequently in those who received the investigational drug versus placebo.

Thirty-day and 60-day all-cause mortality were similar between the two groups.


  1. Ravandi F, Ritchie EK, Sayar H, et al. Vosaroxin plus cytarabine versus placebo plus cytarabine in patients with first relapsed or refractory acute myeloid leukemia (VALOR): a randomised, controlled, double-blind, multinational, phase 3 trial. Lancet Oncol. 2015. [epub ahead of print]. doi: 10.1016/S1470-2045(15)00201-6.