New phase III safety data for Qinprezo (vosaroxin) + CPX 351 (cytarabine) in acute myeloid leukemia- Sunesis Pharmaceuticals

An analysis of the Phase III VALOR trial of Qinprezo (vosaroxin), from Sunesis Pharmaceuticals, plus CPX 351 (cytarabine), in relapsed/refractory acute myeloid leukemia (AML) has been presented at the 57th American Society of Hematology Annual Meeting. A total of 705 patients from VALOR were included in the safety population (355 treated with vosaroxin/cytarabine and 350 treated with placebo/cytarabine). Rates of 30-day (7.9% vs 6.6%, respectively) and 60-day (19.7% vs 19.4%, respectively) mortality in VALOR were comparable between vosaroxin plus cytarabine and placebo plus cytarabine arms. Several individual baseline factors independently predicted risk of early mortality, including ECOG performance status, hemoglobin, bilirubin and albumin levels, intermediate or high bone marrow blasts, and prior myelodysplastic syndrome. The previously validated TRM score for predicting early mortality in newly diagnosed AML was also predictive of mortality in this relapsed/refractory population. Vosaroxin/cytarabine treatment and age were not significant predictors of early mortality.

Comment: Qinprezo (vosaroxin) is an anti-cancer quinolone derivative, a class of compounds that has not been used previously for the treatment of cancer. Preclinical data demonstrate that vosaroxin both intercalates DNA and inhibits topoisomerase II, resulting in replication-dependent, site-selective DNA damage, G2 arrest and apoptosis.