ESA benefits lower-risk MDS patients
COPENHAGEN—The erythropoiesis-stimulating agent (ESA) darbepoetin alfa can provide a clinical benefit in patients with lower-risk myelodysplastic syndromes (MDS), a phase 3 trial suggests.
In the ARCADE trial, darbepoetin alfa significantly reduced the incidence of red blood cell (RBC) transfusions in patients with low- and intermediate-1 risk myelodysplastic syndrome (MDS), when compared to placebo.
The ESA also significantly improved erythroid response.
In addition, researchers said adverse events (AEs) were generally balanced between the darbepoetin alfa and placebo arms.
Uwe Platzbecker, MD, of University Hospital Carl Gustav Carus Dresden in Germany, presented these results at the 21st Congress of the European Hematology Association (abstract S128). The ARCADE trial was sponsored by Amgen.
Dr Platzbecker noted that, although ESAs are recommended in clinical guidelines to treat anemia in patients with lower-risk MDS, the drugs are not widely approved for this indication.
So, in the ARCADE trial, he and his colleagues assessed darbepoetin alfa in patients with low- or intermediate-1 risk MDS who had not previously taken ESAs or biologic response modifiers.
The patients had hemoglobin levels ≤10 g/dL, endogenous erythropoietin levels ≤500 mU/mL, and low transfusion burden (<4 RBC units in each of 2 consecutive 8-week periods prior to randomization).
During a 24-week period, 147 patients received either darbepoetin alfa at 500 μg (n=97) or placebo (n=49) every 3 weeks. The ESA dose was withheld if patients’ hemoglobin was >12.0 g/dL and decreased if hemoglobin increased by >1.5 g/dL in 3 weeks without transfusion.
At week 25, when the primary and key secondary endpoints were assessed, patients underwent an end-of-treatment period visit. They could then enter a 48-week active treatment period and cross over to receive darbepoetin alfa, with dose escalation allowed beginning on week 31. Treatment continued until week 72 or 73, and patients continue to be assessed every 26 weeks, for a minimum of 3 years.
Patient characteristics
Dr Platzbecker said baseline demographic and disease characteristics were generally similar between the treatment arms. All patients were Caucasian, and about 55% were male. The median age was 74 (range, 67-79). About half of patients in each treatment arm belonged to the low-risk IPSS category.
In both arms, most patients had refractory cytopenia with multilineage dysplasia (38.8% in the placebo arm and 46.4% in the darbepoetin alfa arm). Patients also had refractory anemia with excess blasts-1 (20.4% and 13.4%, respectively), refractory anemia (26.5% and 9.3%), refractory anemia with ring sideroblasts (8.2% and 17.5%), 5q deletion (4.1% and 11.3%), unclassifiable MDS (2.0% and 1.0%), and MDS of an unknown type (0% and 1.0%).
In the 16 weeks before randomization, 58.2% of all patients—53.1% in the placebo arm and 60.8% in the darbepoetin alfa arm—did not have any RBC transfusions. About 25% (24.7%)—22.4% in the placebo arm and 25.8% in the darbepoetin alfa arm—received 1 to 3 RBC units. And 17.1%—24.5% in the placebo arm and 13.4% in the darbepoetin alfa arm—received 4 or more RBC units.
Dosing
During the 24-week double-blind period of the study, 77% (37/48) of patients in the placebo arm and 79% (77/98) in the darbepoetin alfa arm received all 8 doses of treatment.
Sixteen percent (n=16) of patients in the darbepoetin alfa arm had a single dose reduction, and 2% (n=2) had 2 dose reductions. None of the patients in the placebo arm had a dose reduction.
Eleven percent of patients in the darbepoetin alfa arm had doses withheld due to increased hemoglobin. The dose was withheld once for 6 patients, twice for 4 patients, and 3 times for 1 patient. None of the placebo-treated patients had a dose withheld for this reason.
