Indications
Emicizumab is used for routine prevention (prophylaxis) of bleeding episodes in people with haemophilia A, a lifelong inherited bleeding disorder caused by a lack of clotting factor VIII. It is used in adults and children of all ages, both in those who have developed inhibitors (antibodies) against factor VIII and in those without inhibitors who have severe or moderate disease, as decided by a haematologist. It is not used to treat a bleed that is already happening.
How It Works
Emicizumab is a bispecific monoclonal antibody: one arm attaches to activated factor IX and the other to factor X. By holding these two clotting factors together, it does the job that missing factor VIII normally does, allowing the clotting cascade to continue and a stable clot to form. Because it is not factor VIII, inhibitors against factor VIII do not block it.
Dosage and Administration
Emicizumab is a specialist medicine given as an injection under the skin (abdomen, thigh or upper arm). Treatment usually starts with weekly loading doses for the first 4 weeks, followed by maintenance doses every 1, 2 or 4 weeks. All doses are calculated from body weight and given exactly as prescribed by the haematologist. After training, patients or carers can give the injections at home. Do not inject into moles, scars, bruised or tender skin.
Interactions
- Activated prothrombin complex concentrate (aPCC), especially at high cumulative doses, used to treat breakthrough bleeds while on Emicizumab, has caused thrombotic microangiopathy and blood clots; avoid it if possible and use only on specialist advice, at the lowest effective dose
- Recombinant factor VIIa or factor VIII may be used for breakthrough bleeds as directed by the specialist
- Emicizumab affects some blood clotting tests (such as aPTT and tests based on it), so laboratory results must be interpreted by the specialist
Contraindications
- Allergy to Emicizumab or any ingredient
Side Effects
Common effects include injection site reactions (redness, itching, pain, swelling), headache, joint pain, fever, diarrhoea and muscle pain. Rare but serious effects are thrombotic microangiopathy (damage to small blood vessels with kidney problems) and blood clots, mainly when aPCC has been used.
Get urgent medical help for confusion, weakness, swelling of the arms or legs, yellowing of the skin or eyes, stomach or back pain, nausea or vomiting, passing less urine, chest pain, shortness of breath, sudden severe headache, or signs of a severe allergic reaction. Also seek help for any bleeding that does not stop.
Pregnancy and Lactation
There is little information in pregnancy. Women who could become pregnant should use effective contraception during treatment and for 6 months after the last dose. It is not known whether it passes into breast milk; the decision to breastfeed should be made with the haematologist.
Precautions and Warnings
Carry information that you use Emicizumab and tell every doctor, dentist and laboratory. Discuss with your haematologist how to treat breakthrough bleeds and what to do before surgery. Do not stop treatment without advice.
Overdose
Experience with overdose is limited; it could increase the risk of blood clots. Contact the doctor if too much is given; the patient will be monitored.
Therapeutic Class
Antihaemorrhagic; bispecific monoclonal antibody (factor VIII mimetic).
Storage
Store in a refrigerator at 2 to 8°C, do not freeze, and keep the vial in the outer carton to protect from light. Do not shake. Keep out of the reach of children.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.