New & approved: Aranesp & Foradil & Entocort EC. (Primary Care).

Aranesp

(darbepoetin alfa, Amgen)

A recombinant erythropoiesis-stimulating protein for treating anemia associated with chronic renal failure (CRF), in people on dialysis and those not on dialysis. Like epoietin alfa (Procrit and Epogen), Aranesp acts like endogenous erythropoietin, stimulating red blood cell production, but has a longer half-life and can be administered less frequently.

* Dosage: Start at 0.45 [micro]g/kg IV or subcutaneously once a week; adjust dose to maintain target hemoglobin level between 11 and 12 g/dL. Some CRF patients can be maintained with one subcutaneous dose every 2 weeks; dose may need to be altered every few weeks. Patients can switch from Epogen or Procrit to Aranesp. Better pharmacokinetics make subcutaneous administration preferable, said Dr. Ravi Thadhani, staff nephrologist at Massachusetts General Hospital, Boston.

* Special Considerations: The most important side effect is an increase in blood pressure, which requires dose alterations; contraindicated in uncontrolled hypertension. This is a class effect. Other side effects include hypotension, myalgias, headache, and diarrhea.

* Comment: Trials of Aranesp in CRF patients included a study of predialysis patients; 93% of those on Aranesp once a week and 92% of those on epoetin alfa three times a week reached target hemoglobin levels after 24 weeks. Aranesp will have the greatest impact on predialysis patients with kidney disease, said Dr. Thadhani, one of the investigators. Most of these patients have hypertension and/or diabetes and take several medications; a single subcutaneous injection administered at home every week or two "would not compete" with other medications and should significantly help with compliance.

Patients with CRF typically develop asymptomatic anemia well before they need dialysis; if untreated they gradually develop left ventricular hypertrophy, heart failure, and death, noted Dr. Thadhani, who is on Amgen's speakers bureau.