According to results presented at the 27th annual San Antonio Breast Cancer Symposium (SABCS), Aranesp® (darbepoetin alfa) is at least as effective as epoetin alfa (Procrit®) but requires significantly less dosing for the treatment of chemotherapy-induced anemia in breast cancer patients. The number of injections of Aranesp® is reduced by half compared to epoetin alfa, as Aranesp® is only necessary once every two weeks, while epoetin alfa is required every week.
Anemia is a term that refers to low levels of circulating red blood cells (RBCs) in the blood. Red blood cells are responsible for delivering oxygen to tissues throughout the entire body. Bone marrow (spongy material inside large bones) is stimulated to produce RBCs by a chemical substance called erythropoietin, which is produced by the kidneys. Each RBC contains many molecules of hemoglobin, a protein-iron complex that is responsible for the delivery of oxygen to the cells and carbon dioxide to the lungs.
Common symptoms caused by anemia include fatigue, shortness of breath, greatly diminished activity levels and a reduced overall feeling of well-being. Severe anemia often necessitates blood transfusions, which have associated risks of infection, rejection, and increased medical costs. Furthermore, severe anemia may cause a delay or reduction in the dose of cancer treatment which can lead to inferior treatment outcomes.
Erythropoietin can be manufactured outside the body and administered to cancer patients to treat their anemia. Recombinant human erythropoietin, or epoetin alfa, a commonly used drug for cancer patients receiving treatment, is comprised of manufactured erythropoietin. Epoetin alfa has been shown to reduce the severity of anemia and reduce symptoms of fatigue in patients receiving chemotherapy treatment by stimulating the bone marrow to produce more RBCs. Currently, Aranesp® and epoetin alfa are two forms of manufactured erythropoietin most often utilized for the treatment of anemia in the United States. Aranesp®, which requires less frequent dosing than epoetin alfa, has been approved by the FDA for the treatment of anemia caused by chemotherapy in non-myeloid cancers, or cancers that do not originate in blood cells. Less frequent dosing results in fewer injections and fewer office visits for patients, reducing the need for patients and caregivers to take time off from work or leisure. The use of Aranesp® is gaining momentum in the clinical setting as results from clinical trials continue to indicate its effectiveness in comparison to epoetin alfa.
The recent multi-center trial presented at SABCS included 141 patients with breast cancer and chemotherapy-induced anemia. Patients were treated with either Aranesp® once every two weeks or epoetin alfa every week and then directly compared. Overall, the achievement and maintenance of appropriate hemoglobin levels (a measurement of anemia) occurred in 93% of patients treated with Aranesp®, compared with 90% of patients treated with epoetin alfa. The average time to reach the target hemoglobin levels was 3 weeks for those treated with Aranesp® and 4 weeks for those treated with epoetin alfa. During the study, only 6% of patients treated with Aranesp® required blood transfusions, compared with 16% of patients treated with epoetin alfa. Treatment with both Aranesp® and epoetin alfa was well tolerated.
The researchers concluded that these results provide further evidence that Aranesp® is as effective as epoetin alfa for the treatment of chemotherapy-induced anemia and actually reduced the rate of blood transfusions necessary in this group of patients with breast cancer. Because of the less frequent dosing schedule of Aranesp®, patients received half as many injections and spent less time receiving treatment for anemia than patients treated with epoetin alfa.
Reference: Schwartzberg L, et al. Randomized head-to-head trial shows Aranesp dosed every two weeks is comparable to epoetin alfa dosed once a week in breast cancer. Proceedings from the 27th annual San Antonio Breast Cancer Symposium (SABCS). December 2004. Abstract #6030.