Phase III Valor trial of vosaroxin in AML fails to meet endpoint - Sunesis

Sunesis Pharma has announced results from the pivotal Phase III VALOR trial, a randomized, double-blind, placebo-controlled trial of vosaroxin and cytarabine in patients with first relapsed or refractory Acute Myeloid Leukemia (AML). The trial enrolled 711 patients, who were stratified for age, geography and disease status. The trial did not meet its primary endpoint of demonstrating a statistically significant improvement in overall survival, with a median overall survival of 7.5 months for vosaroxin and cytarabine compared to 6.1 months for placebo and cytarabine. Because transplant may confound the primary analysis, a predefined analysis of overall survival censoring for stem cell transplantation was planned.

In this analysis, patients receiving the vosaroxin combination had a median overall survival of 6.7 months versus 5.3 months for placebo and cytarabine. The trial also demonstrated a clinically significant benefit in complete remission rate (30.1% vs 16.3%), the secondary endpoint. In the analysis of patients aged 60 years and older, where the rate of stem cell transplant was 20.2%, the vosaroxin combination demonstrated a median overall survival of 7.1 months, versus 5.0 months for placebo and cytarabine, and a CR rate of 31.9% versus 13.8%.

Grade 3 or higher non-hematologic adverse events that were more common in the vosaroxin combination arm were gastrointestinal and infection-related toxicities. The rate of serious adverse events was 55.5% in the vosaroxin combination arm compared to 35.7% in the placebo and cytarabine arm. Based on results of the trial, Sunesis plans to commence a marketing authorization application with the European Medicines Agency (EMA) and to meet with the U.S. Food and Drug Administration to determine the appropriate regulatory path forward.