Photo courtesy of ASH
VIENNA—Adding the anticancer quinolone derivative vosaroxin to treatment with cytarabine can improve outcomes for some older patients with relapsed/refractory acute myeloid leukemia (AML), results of the phase 3 VALOR trial suggest.
AML patients age 60 and older with refractory and early relapse disease had improved survival rates when they received vosaroxin and cytarabine, compared to patients who received cytarabine and placebo.
However, for older patients with late-relapse AML, the addition of vosaroxin had no significant impact on survival.
Farhad Ravandi, MD, of the University of Texas MD Anderson Cancer Center in Houston, and his colleagues presented these result at the 20th Congress of the European Hematology Association (abstract P197*). The trial was sponsored by Sunesis Pharmaceuticals, the company developing vosaroxin.
“AML is a disease that primarily affects older patients, and clinical outcomes among these patients is abysmal,” Dr Ravandi noted. “These patients have had few options outside of clinical trial enrollment.”
“Results from the analyses presented today show compelling survival and durable responses, with comparable early mortality, for the vosaroxin and cytarabine treatment arm in the older refractory and early relapse patients. Given these results, I believe vosaroxin represents an important new treatment option.”
VALOR is a randomized, double-blind, phase 3 trial that enrolled 711 adult patients with relapsed or refractory AML. Patients were stratified for age, geographic region, and disease status, then randomized 1:1 to receive vosaroxin and cytarabine or placebo and cytarabine.
Dr Ravandi and his colleagues presented results from the subgroups of patients age 60 years and older (451/711) with late-relapse disease (n=87) and refractory or early relapse disease (combined n=364).
Late-relapse disease
Patients with late-relapse disease had a significantly higher complete response (CR) rate if they received vosaroxin/cytarabine rather than placebo/cytarabine. The rates were 57% and 28%, respectively (P=0.0064).
However, there was no significant difference between the treatment arms with regard to overall survival (OS), leukemia-free survival (LFS), or event-free survival (EFS).
The median OS was 9.2 months in the vosaroxin/cytarabine arm and 9.8 months in the placebo/cytarabine arm (hazard ratio [HR]=1.06, P=0.82). The median OS, censored for transplant, was 9.1 months in both arms (HR=0.92, P=0.78).
The median LFS was 10.3 months in the vosaroxin/cytarabine arm and 8.7 months in the placebo/cytarabine arm (HR=1.16, P=0.77). And the median EFS was 5.5 months and 2.3 months, respectively (HR=0.65, P=0.0852).
Thirty-day all-cause mortality was 11% the vosaroxin/cytarabine arm and 2% in the placebo/cytarabine arm. Sixty-day all-cause mortality was 18% and 14%, respectively.
Refractory/early relapse disease
Patients with refractory AML (n=210) and those with early relapse disease (n=154) had significant improvements in CR and survival when they received vosaroxin and cytarabine. The CR rate was 26% in the vosaroxin/cytarabine arm and 10% in the placebo/cytarabine arm (P=0.0001).
The median OS was 6.5 months in the vosaroxin/cytarabine arm and 3.9 months in the placebo/cytarabine arm (HR=0.69, P=0.0008). The median OS, censored for transplant, was 6.2 months and 3.9 months, respectively (HR=0.71, P=0.0048).
The median LFS was 9.7 months in the vosaroxin/cytarabine arm and 5.5 months in the placebo/cytarabine arm (HR=0.50, P=0.0424). And the median EFS was 1.7 months and 1.3 months, respectively (HR=0.59, P<0.0001).
Rates of all-cause mortality were comparable between the arms. Thirty-day all-cause mortality was 10% in the vosaroxin/cytarabine arm and 11% in the placebo/cytarabine arm. Sixty-day all-cause mortality was 21% and 25%, respectively.
Adverse events
Ninety-four percent of patients in the vosaroxin/cytarabine arm and 86% of those in the placebo/cytarabine arm experienced a grade 3 or higher adverse event (AE). The rate of treatment-related, grade 3 or higher AEs was 74% and 60%, respectively.
The most common grade 3 or higher AEs—occurring in at least 10% of patients in the vosaroxin/cytarabine and placebo/cytarabine arms, respectively—were febrile neutropenia (43% vs 30%), thrombocytopenia (24% vs 25%), anemia (23% vs 24%), neutropenia (19% vs 14%), hypokalemia (15% vs 7%), stomatitis (16% vs 4%), sepsis (12% vs 6%), and pneumonia (11% vs 8%).
*Information in the abstract differs from that presented at the meeting.