Aranesp® Effectively Treats Anemia in Patients with Low-risk Myelodysplastic Syndrome

According to results presented at the 2006 annual meeting of the American Society of Clinical Oncology (ASCO), Aranesp® (darbepoetin alfa) administered every three weeks increases red blood cell counts in patients with low-risk myelodysplastic syndrome.

Myelodysplastic syndromes (MDS) are a group of diseases marked by abnormal production of blood cells by the bone marrow. Healthy bone marrow produces immature blood cells—called blasts—that then develop into red blood cells, white blood cells, and platelets. MDS disrupts this normal process so that the bone marrow is overactive, producing many immature cells. These blasts, however, do not fully develop into mature blood cells. As a result, patients with MDS have fewer mature blood cells, and those they do have may be abnormal and not function properly.

Any or all blood cell types may be affected by MDS, which is different from leukemia in which only white blood cells are overproduced. The direct effects of MDS may include:

Anemia and fatigue if red blood cells counts are low.
Increased risk of infection if white blood cell counts are low.
Compromised ability to control bleeding if platelet counts are low.
Anemia can be treated with a red blood cell transfusion or by increasing red blood cell production with a naturally produced protein called erythropoietin. Erythropoietin stimulates the bone marrow to produce more red blood cells. When administered to some patients, it reduces the severity of anemia and can prevent red blood cell transfusions.

Forms of erythropoietin that are currently available include epoetin alfa (Epogen® or Procrit®) and darbepoetin alfa (Aranesp®). Aranesp is a longer acting form that can be administered less frequently. Aranesp has not yet been approved by the FDA for the treatment of anemia associated with MDS.

To evaluate the use of Aranesp to treat anemia in patients with low- or intermediate risk MDS, researchers are conducting an ongoing 52-week phase II trial involving more than 200 patients. Aranesp (500 mcg) is administered every three weeks. Previous preliminary results from this study indicated that low-risk MDS patients can experience a significant increase in red blood cell count after 13 weeks of Aranesp.

The results presented at ASCO 2006 focused on 27/28 weeks of follow-up.

Among patients who had not previously received medication to increase red blood cell count, 74% of patients achieved the target hemoglobin level of 11 g/dL. None of the patients required a transfusion during the 27/28 week observation period.
Among patients who had previously received medication to increase red blood cell count, 49% of patients achieved the target hemoglobin level of 11 g/dL. Five percent of patients received at least one transfusion during the 27/28 week observation period.
Three complications related to blood clots have occurred thus far.
The researchers conclude that these preliminary results suggest that Aranesp every three weeks is well tolerated and increases red blood cell count in anemic patients with low-risk MDS.

Reference: Paquette R, Gabrilove J, Lyons R et al. Darbepoetin Alfa for Treating Anemia in Low-risk Myelodysplastic Syndrome Patients: Interim Results after 27/28 Weeks. Presented at the 2006 ASCO Annual Meeting. Abstract 6564.