Darbesis60 mcg/0.3 ml

Darbepoetin alfa is a long-acting erythropoiesis-stimulating agent (ESA) used for:

• Treatment of anaemia due to chronic kidney disease (CKD), in patients on dialysis and patients not on dialysis
• Treatment of anaemia caused by concomitant myelosuppressive chemotherapy in patients with non-myeloid malignancies, when the anaemia is not due to another correctable cause, and the chemotherapy is planned for a minimum of two additional months

Darbepoetin alfa is not indicated for patients receiving myelosuppressive chemotherapy when the anticipated treatment outcome is cure, and should be discontinued following the completion of a chemotherapy course. It is not intended as a substitute for red blood cell (RBC) transfusion in patients who require immediate correction of anaemia, and has not been shown to improve quality of life, fatigue, or general well-being.

Contains Darbesis 60 mcg/0.3 ml, a hyperglycosylated erythropoiesis-stimulating protein produced by recombinant DNA technology, as the active ingredient, supplied as an injectable solution in various single-dose vial or pre-filled syringe strengths (commonly 25 mcg, 40 mcg, 60 mcg, 100 mcg, and 200 mcg).

Darbepoetin alfa is a laboratory-made version of erythropoietin, the hormone the body normally produces (mainly in the kidneys) to stimulate the bone marrow to produce red blood cells. It is used to treat anaemia caused by chronic kidney disease or by certain chemotherapy regimens. Because it is more heavily glycosylated than earlier erythropoiesis-stimulating agents, it has a longer half-life, allowing less frequent dosing. Darbepoetin alfa carries an important boxed warning: using ESAs to raise haemoglobin above a certain target level increases the risk of death, heart attack, stroke, and blood clots, and in certain cancers has been shown to shorten survival or increase tumour progression - so it is used at the lowest dose needed to reduce the need for blood transfusion, not to normalize haemoglobin levels.

Therapeutic Class: Erythropoiesis-Stimulating Agent (ESA)

Darbepoetin alfa has additional sialic acid-containing carbohydrate chains compared to endogenous erythropoietin and epoetin alfa, giving it an approximately three-fold longer serum half-life and allowing less frequent dosing (weekly or every-2-weeks, compared to the more frequent dosing needed with shorter-acting ESAs). It stimulates erythropoiesis by the same mechanism as the body's own erythropoietin.

• Given by subcutaneous or intravenous injection, by or under the direction of a trained healthcare professional
• Do not shake the vial or syringe vigorously, as this can denature the protein and reduce its effectiveness
• Use only one dose per vial/syringe; do not re-enter or reuse
• Iron status should be evaluated before and periodically during treatment, and iron supplementation given as needed, since adequate iron stores are required for the drug to work effectively

No significant drug-drug interactions have been well established with Darbesis 60 mcg/0.3 ml; however, the following clinical considerations apply:

• Iron supplements: often needed alongside Darbesis 60 mcg/0.3 ml, since adequate iron stores are essential for an adequate response; iron deficiency is a common cause of poor or diminished response.
• Other medicines affecting blood pressure: Darbesis 60 mcg/0.3 ml can raise blood pressure, so antihypertensive therapy may need adjustment during treatment.
• Anticoagulants (in dialysis patients): increased haemoglobin/haematocrit may require adjustment of heparin dosing during dialysis to prevent clotting of the extracorporeal circuit.

Common side effects

• Hypertension
• Fatigue
• Nausea, vomiting, diarrhoea
• Muscle and joint pain
• Peripheral oedema (swelling)
• Injection site reactions

Serious side effects (boxed warnings - require prompt medical attention)

• Increased mortality, myocardial infarction, stroke, and thromboembolism: using ESAs to target a haemoglobin level above 11 g/dL increases the risk of serious cardiovascular events without providing additional benefit; report chest pain, shortness of breath, weakness on one side, or leg swelling and pain immediately.
• Venous thromboembolism and thrombosis of vascular access: report sudden swelling, pain, or warmth in a limb, or problems with a dialysis access site.
• Increased tumour progression or recurrence, and shortened survival in certain cancers (including breast, non-small cell lung, head and neck, lymphoid, and cervical cancers) when ESAs are used in these settings - use only for chemotherapy-associated anaemia, at the lowest dose needed, and discontinue after the chemotherapy course ends.
• Hypertensive encephalopathy and seizures, reported in CKD patients - blood pressure must be adequately controlled before and during treatment.
• Pure red cell aplasia (PRCA): if severe anaemia with a low reticulocyte count develops during treatment, evaluate for this rare but serious condition.
• Severe allergic reactions and severe cutaneous reactions (rare) - discontinue immediately if suspected.

Pregnancy

Data on Darbesis 60 mcg/0.3 ml use in human pregnancy are limited; use during pregnancy should only occur if the treating physician determines the potential benefit outweighs the potential risk, given the seriousness of the underlying condition (CKD anaemia or chemotherapy-associated anaemia) being treated.

Breastfeeding

It is not known whether Darbesis 60 mcg/0.3 ml passes into human milk; use during breastfeeding should be discussed with the treating physician.

• Use the lowest dose sufficient to reduce the need for RBC transfusions - no trial has identified a haemoglobin target, dose, or dosing strategy that avoids the increased cardiovascular and mortality risks associated with ESAs.
• Control blood pressure adequately before and during treatment, given the risk of hypertensive encephalopathy and seizures; reduce or withhold Darbesis 60 mcg/0.3 ml if blood pressure becomes difficult to control.
• In cancer patients: use only for anaemia caused by concomitant myelosuppressive chemotherapy, not for anaemia from other causes, and discontinue following completion of the chemotherapy course.
• Iron monitoring: evaluate iron status before and periodically during treatment, and correct any deficiency, since inadequate iron stores are a common reason for poor response.
• Monitor haemoglobin regularly, with dose adjustments made based on the rate of rise and current level, and not more frequently than every 4 weeks.

Overdose can lead to an excessive rise in haemoglobin, increasing the risk of the serious cardiovascular and thromboembolic events associated with this drug class. Suspected overdose should be evaluated by a healthcare professional; treatment is generally supportive, and phlebotomy (blood removal) may be used to manage a significantly elevated haemoglobin level in cases of serious overdose, as clinically indicated by the treating physician.

Store in a refrigerator at 2-8°C, protected from light; do not freeze or shake. Do not use if the vial or syringe has been frozen or exposed to excessive heat. Discard any unused portion, since these are single-dose containers without preservative.

• Elderly: Used with the same dosing approach as younger adults, with appropriate monitoring given increased likelihood of underlying cardiovascular disease.
• Patients with cardiovascular disease or stroke: Use with particular caution, given the increased cardiovascular risk associated with this drug class.
• Cancer patients: Safety and efficacy have not been established in cancer patients younger than 18 years.
• Patients undergoing surgery: Increased risk of deep venous thrombosis has been noted with ESA use in the perisurgical period; appropriate DVT prophylaxis is recommended.

For CKD-related anaemia, Darbesis 60 mcg/0.3 ml is typically used long-term, with the dose periodically adjusted based on haemoglobin response. For chemotherapy-associated anaemia, it is used only for the duration of the myelosuppressive chemotherapy course and discontinued once chemotherapy is completed.

Drug Class: Recombinant human erythropoietin analogue (hyperglycosylated)

Darbepoetin alfa binds to and activates the erythropoietin receptor on red blood cell precursor cells in the bone marrow, stimulating their proliferation and differentiation into mature red blood cells. This increases red blood cell production, raising haemoglobin and reducing the symptoms and transfusion needs associated with anaemia due to chronic kidney disease or chemotherapy-induced bone marrow suppression.

Darbepoetin alfa is used in pediatric patients with anaemia due to chronic kidney disease, with dosing individualized by the treating specialist based on weight and haemoglobin response. Safety and effectiveness for the chemotherapy-associated anaemia indication have not been established in cancer patients younger than 18 years.