Darbepoetin Alfa

Darbepoetin alfa stimulates erythropoiesis by the same mechanism as endogenous erythropoietin. Erythropoietin interacts with progenitor stem cells to increase red cell production. Binding of erythropoietin to the erythropoietin receptor leads to receptor dimerization, which facilitates activation of JAK-STAT signaling pathways within the cytosol. Activated STAT (signal transducers and activators of transcription) proteins are then translocated to the nucleus where they serve as transcription factors which regulate the activation of specific genes involved in cell division or differentiation.

Usual Adult Dose for Anemia Associated with Chronic Renal Failure:

Chronic Kidney Disease (CKD) Patients Not on Dialysis:

• Initial dose: 0.45 mcg/kg IV or subcutaneously once every 4 weeks as appropriate
• Comments: Initiate treatment only when hemoglobin is less than 10 g/dL, rate of hemoglobin decline indicates likelihood of requiring RBC transfusion, and reducing risk of alloimmunization and/or other RBC transfusion-related risks is a goal.

CKD Patients on Dialysis:

• Initial dose: 0.45 mcg/kg IV or subcutaneously once a week or 0.75 mcg/kg once every 2 weeks as appropriate
• Comments: Initiate treatment when hemoglobin is less than 10 g/dL. IV route is recommended for patients on hemodialysis.

 

Usual Adult Dose for Anemia Associated with Chemotherapy:

• Initial dose: 2.25 mcg/kg subcutaneously once a week or 500 mcg subcutaneously once every 3 weeks
• Duration of therapy: Until completion of chemotherapy course
• Comments: Initiate treatment if hemoglobin is less than 10 g/dL and a minimum of 2 additional months of chemotherapy is planned. Use the lowest dose necessary to avoid RBC transfusions.
• Use: Treatment of anemia in patients with non-myeloid malignancies where anemia is due to the effect of concomitant myelosuppressive chemotherapy.

Antagonism of hypotensive effect and increased risk of hyperkalemia with ACE inhibitors and angiotensin II receptor antagonists. Ethanol.

Darbepoetin is contraindicated in patients with:

• Uncontrolled hypertension
• Pure red cell aplasia (PRCA) that begins after treatment with Darbepoetin or other erythropoietin protein drugs
• Serious allergic reactions to Darbepoetin

Increased Mortality, Myocardial Infarction, Stroke, and Thromboembolism; Increased Mortality and/or Increased Risk of Tumor Progression or Recurrence in Patients with cancer; Hypertension; Seizures; Serious allergic reaction; Severe Cutaneous Reactions

Pregnancy Category C. It is not known whether Darbepoetin Alfa is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when Darbepoetin Alfa is administered to a nursing woman.

Pregnancy and lactation, children. Hypertension; history of seizures; hepatic impairment; sickle cell anaemia; sudden stabing migraine-like pain (warning sign of hypotensive crisis); exclude other causes of anaemia; ischaemic vascular disease; thrombocytosis; epilepsy; malignant disease; increase in heparin dose may be needed; increased risk of thrombosis when used for anaemia before orthopedic surgery; CV disease including recent MI/cerebrovascular accident. Monitor haemoglobin, BP and electrolytes; platelet count for 1st 8 wk.

Pediatric Use:

• Pediatric Patients With CKD: Darbepoetin safety and efficacy were similar between adults and pediatric patients with CKD when Darbepoetin was used for initial treatment of anemia or patients were transitioned from treatment with epoetin alfa to Darbepoetin
• Pediatric Patients With Cancer: The safety and efficacy of Darbepoetin in pediatric patients with cancer have not been established.

Geriatric Use: Of the 1801 patients with CKD in clinical studies of Darbepoetin, 44% were age 65 and over, while 17% were age 75 and over. Of the 873 patients in clinical studies receiving Darbepoetin and concomitant cancer chemotherapy, 45% were age 65 and over, while 14% were age 75 and over. No differences in safety or efficacy were observed between older and younger patients.

Haematopoietic Agents

Darbepoetin overdosage can cause hemoglobin levels above the desired level, which should be managed with discontinuation or reduction of Darbepoetin dosage and/or with phlebotomy, as clinically indicated. Cases of severe hypertension have been observed following overdose with ESAs

Store at 2°C to 8°C. Do not freeze. Do not shake. Protect from light; store Darbepoetin Alfa in the carton until use. Do not use Darbepoetin Alfa that has been shaken or frozen.