Patient Leaflet Updated 10-Oct-2024 | LFB Biopharmaceuticals Limited
Willfact 500/1000/2000 IU Powder and solvent for solution for injection
WILLFACT 500 IU powder and solvent for solution for injection
WILLFACT 1000 IU powder and solvent for solution for injection
WILLFACT 2000 IU powder and solvent for solution for injection
human von Willebrand factor
1. What Willfact is and what it is used for
2. What you need to know before you use Willfact
3. How to use Willfact
4. Possible side effects
5. How to store Willfact
6. Contents of the pack and other information
Willfact is made from human plasma (the liquid part of the blood) and contains the active substance called human von Willebrand factor (VWF).
VWF is involved in blood clotting. Lack of this factor, such as in von Willebrand disease, means that blood does not clot as quickly as it should, so there is an increased tendency to bleed. The replacement of VWF by Willfact will temporarily repair blood clotting mechanisms.
Willfact is indicated in the prevention and treatment of surgical or other bleeding in patients with von Willebrand disease when desmopressin (DDAVP) treatment alone is ineffective or contra-indicated.
WILLFACT can be used for all age groups.
Willfact should not be used in the treatment of Haemophilia A.
Your treatment with Willfact should always be supervised by a doctor experienced in the treatment of haemostatic disorders.
If you experience heavy bleeding and a blood examination shows that your factor VIII blood value is reduced, you will receive the VWF preparation in addition to a factor VIII preparation within the first twelve hours.
Allergic reactions
As with every protein medicine for intravenous use derived from human blood or plasma, hypersensitivity reactions in the form of an allergy may occur.
During the injection you will be monitored to detect any early sign of hypersensitivity. These include rash (hives or generalised urticaria), tightness of the chest, wheezing, drop in blood pressure (hypotension) and severe allergic reactions (anaphylaxis).
Your doctor will inform you of the warning signs of an allergic reaction.
Should signs or symptoms of hypersensitivity occur, treatment should be discontinued and you should seek immediate medical attention.
Virus safety
When medicines are made from human blood or plasma, certain measures are put in place to prevent infections being passed on to patients. These include:
Despite these measures, when medicines prepared from human blood or plasma are administered, the possibility of passing on infection cannot be totally excluded. This also applies to any unknown or emerging viruses or other types of infections.
The measures taken are considered effective for enveloped viruses such as human immunodeficiency virus (HIV-AIDS), hepatitis B virus and hepatitis C virus.
The measures taken may be of limited value against non-enveloped viruses such as hepatitis A virus and parvovirus B19. Parvovirus B19 infection may be serious for pregnant women (as there is a risk of infection of the unborn child) and for individuals whose immune system is depressed or who have some types of anaemia (e.g. sickle cell disease or haemolytic anaemia).
Vaccinations
Your doctor may recommend that you consider vaccination against hepatitis A and B if you regularly/repeatedly receive human plasma-derived von Willebrand factor.
Recording of batch number
It is strongly recommended that every time you receive a dose of Willfact, the name and batch number of the medicine are recorded in order to maintain a record of the batches used.
Risk of thrombosis
Blood vessels may also become blocked by blood clots (thromboses).
This risk exists particularly if your previous medical history or laboratory results indicate that you present certain risk factors.
In this case you will be monitored very carefully for the early signs of thrombosis, and a preventive treatment (prophylaxis) against vein blockages by blood clots should be introduced.
When using a factor VIII-containing von Willebrand factor product, your doctor should be aware that the continued treatment may cause an excessive rise in FVIII. If you receive such FVIII-containing VWF product, your doctor should monitor your FVIII plasma level regularly. This ensures that your FVIII plasma level is not sustained excessively, which may otherwise increase the risk of thrombotic events.
Limited effectiveness
It is possible that, in patients with von Willebrand disease, especially type 3 patients, proteins may be formed that neutralise the effect of VWF. These proteins are called neutralising antibodies or inhibitors. If the laboratory results show that your VWF levels are not being replenished, or if the bleeding does not stop despite a sufficient dose of Willfact, your doctor will check whether VWF inhibitors are being formed in your body. If these inhibitors are present in high concentration, treatment with VWF may not be effective, and other treatment options should be considered. The new treatment will be provided by a doctor who has experience in the treatment of haemostatic disorders.
Tell your doctor or pharmacist if you are using, have recently used or might use any other medicines.
Willfact should be used during pregnancy and breastfeeding only if it is clearly indicated.
The safety of Willfact during pregnancy and breastfeeding has not been evaluated in clinical studies. Animal studies are not sufficient to establish its safety with respect to fertility, pregnancy and development of the child during pregnancy and after birth.
If you are pregnant or breast-feeding, think you may be pregnant or are planning to have a baby, ask your doctor or pharmacist for advice before taking this medicine.
No effects on ability to drive or use machines have been observed.
One 5 mL vial (500 IU) of Willfact contains 0.15 mmol (3.4 mg) sodium.
This is equivalent to 0.17 % of the recommended maximum daily dietary intake of sodium for an adult.
One 10 mL vial (1000 IU) of Willfact contains 0.3 mmol (6.9 mg) sodium.
This is equivalent to 0.35 % of the recommended maximum daily dietary intake of sodium for an adult.
One 20 mL vial (2000 IU) of Willfact contains 0.6 mmol (13.8 mg) sodium.
This is equivalent to 0.69 % of the recommended maximum daily dietary intake of sodium for an adult.
Your treatment should be initiated and monitored by a doctor who is experienced in the treatment of bleeding disorders.
If your doctor thinks that administration could be performed at your home, appropriate instructions will be provided to you by your doctor.
Always take this medicine exactly as your doctor has told you. Check with your doctor if you are not sure.
Preferably, Willfact should be administrated by your doctor or nurse. However, if you have been prescribed Willfact to use at home, your doctor will make sure that you are shown how to inject it and how much to use. Follow the directions given to you by your doctor and ask for help if you have problems handling the syringe, the syringe should always be used by someone trained to use it.
Your doctor will calculate your dose of Willfact (in international units or IU).
The dose depends on:
This dose varies between 40 and 80 IU/kg.
Your doctor will recommend that you undergo blood tests during treatment to control:
Based on the results of these tests, your doctor may decide to adapt the dose and frequency of your injections.
In certain cases, use of a factor VIII preparation (another coagulation protein) in addition to Willfact may be necessary to more rapidly treat or prevent bleeding (in emergency situations or acute bleeding).
Willfact can also be administered as long-term prophylaxis; the dose level is also determined individually in this case. Willfact doses between 40 and 60 IU/kg administered two to three times per week reduce the number of bleeding episodes.
Dosing in children and adolescents is based on bodyweight. In some cases, especially in younger patients (below 6 years), higher doses (up to 100 IU/kg) may be needed.
Please talk to your doctor if you feel that the effect of Willfact is too strong or too weak.
Detailed instructions for reconstitution and administration of the medicinal product are given at the end of the Package Leaflet.
No symptoms of overdose with Willfact have been reported.
However, the risk of thrombosis cannot be excluded in case of major overdose.
If you forget to use Willfact, talk to your doctor.
Do not take a double dose to make up for a forgotten dose.
If you have any further questions on the use of this medicine, ask your doctor, pharmacist or nurse.
Like all medicines, Willfact can cause side effects, although not everybody gets them.
The warning signs of allergic reactions are:
If one of these effects occurs, immediately stop the treatment and alert a doctor to start appropriate treatment depending on the type and severity of the reaction.
Proteins may be formed in patients with von Willebrand disease, especially type 3 patients, which neutralise the effect of VWF. These proteins are called neutralising antibodies or inhibitors. Patients treated with VWF should be carefully monitored by their doctors for the development of inhibitors by appropriate clinical observations and laboratory tests. If such inhibitors occur, the condition can manifest itself as an inadequate clinical response.or occur concomitantly to severe allergic reactions.
There is a risk of formation of blood clots (thrombosis), particularly in patients with known risk factors. After correction of the von Willebrand factor deficiency, you must be monitored for early signs of thrombosis or disseminated intravascular coagulation and receive treatment to prevent thrombosis in situations involving an increased risk of thrombosis (after operations, during confinement to bed, in cases of deficiency in a coagulation inhibitor or fibrinolytic enzyme).
If you receive FVIII-containing VWF preparations, the risk of thrombosis may also be increased due to persistently elevated FVIII plasma levels.
The following side effect has been observed commonly (may affect up to 1 in 10 people):
The following side effects have been observed uncommonly (may affect up to 1 in 100 people):
The other following side effect has been observed with an unknown frequency:
If you get any side effects, talk to your doctor, pharmacist or nurse. This includes any possible side effects not listed in this leaflet.
You can also report side effects directly via the the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.
By reporting side effects you can help provide more information on the safety of this medicine.
Keep this medicine out of the sight and reach of children.
Do not use this medicine after the expiry date, which is stated on the vial label and carton.
Do not store above +25°C. Store in the original container in order to protect from light.
Do not freeze.
For sterility reasons, the product should be used immediately after reconstitution. Chemical and physical in-use stability has, however, been demonstrated for 24 hours at +25°C.
Do not use this medicine if you notice that the solution is cloudy or that it contains any deposit.
Do not throw away any medicines via wastewater or household waste. Ask your pharmacist or your nurse how to throw away medicines you no longer use. These measures will help protect the environment.
The active substance is: human von Willebrand factor (500 IU, 1000 IU or 2000 IU), expressed in International Units (IU) of Ristocetin Cofactor activity (VWF:RCo).
After reconstitution with 5 mL (500 IU), 10 mL (1000 IU) or 20 mL (2000 IU) of water for injections, one vial contains approximately 100 IU/mL of human von Willebrand factor.
Before the addition of albumin, the specific activity is greater than or equal to 60 IU of VWF:RCo/mg of total protein.
The other ingredients are:
Powder: human albumin, arginine hydrochloride, glycine, sodium citrate and calcium chloride dihydrate.
Solvent: water for injections.
Willfact is presented as a white or pale yellow powder or friable solid and a clear or colourless solvent for solution for injection after reconstitution with a transfer system.
Willfact is available in pack sizes of 500 IU/5 mL, 1000 IU/10 mL and 2000 IU/20 mL.
The reconstituted solution should be clear or slightly opalescent, colourless or slightly yellow.
To report a suspected side effect that has not been reported via the Yellow Card Scheme (above), please contact:
This medicine is authorised in the Member States of the European Economic Area and in the United Kingdom (Northern Ireland) under the following names:
Austria Willfact
Czech Republic WILLFACT
Denmark Willfact
Germany WILLFACT
Hungary Willfact
Norway Willfact
Poland Willfact
Slovak Republic Willfact
Spain Willfact
Sweden Willfact
United Kingdom (Northern Ireland) Willfact
This leaflet was last approved in 07/2024.
Posology
Generally, the administration of one IU/kg of von Willebrand factor raises the circulating level of VWF:RCo levels by approximately 0.02 IU/mL (2%).
Levels of VWF:RCo of > 0.6 IU/mL (60%) and FVIII:C of > 0.4 IU/mL (40%) should be achieved.
Haemostasis cannot be ensured until factor VIII coagulant activity (FVIII:C) has reached 0.4 IU/ml (40%). Injection of von Willebrand factor alone does not induce a maximum rise of FVIII:C for at least 6 to 12 hours. It cannot immediately correct the FVIII:C level. Therefore, if the patient’s baseline FVIII:C levels are below this critical level, in all situations where rapid correction of haemostasis is required, such as treatment of a haemorrhage, severe trauma or emergency surgery, factor VIII must be administered with the first injection of von Willebrand factor in order to achieve a haemostatic plasma level of FVIII:C.
However, if an immediate rise in FVIII:C is not necessary, such as in the case of a planned surgery, or if baseline FVIII:C levels are sufficient to ensure haemostasis, the doctor may decide to do without the co-administration of FVIII for the first injection of von Willebrand factor.
For elective surgery, the first injection of Willfact should be given 12 to 24 hours before surgery and the second should be given before the procedure. In such cases, co-administration of a factor VIII product is not required, since endogenous FVIII:C has usually reached the critical level of 0.4 IU/mL (40%) before the intervention. However, this should be confirmed in each patient.
Paediatric population
For each indication, dosing is based on bodyweight. The dose and duration of treatment should be adjusted to the clinical condition of the patient, and their VWF:RCo and FVIII:C plasma levels.
Intravenous administration.
Reconstitution
The currently applicable guidelines for aseptic procedures must be followed. The transfer system is only used to reconstitute the drug, as described below. It is not intended in administering the drug to the patient.
The powder generally dissolves instantaneously and should have dissolved in less than 5 minutes.
The solution should be clear or slightly opalescent, colourless or slightly yellow. The reconstituted product should be inspected visually for particulate matter and discoloration prior to administration.
Do not use solutions that are cloudy or have deposits.
Do not mix with other medicines.
Do not dilute the reconstituted product.
Administration
Storage after reconstitution
For sterility reasons, the product should be used immediately after reconstitution. Chemical and physical in-use stability has, however, been demonstrated for 24 hours at +25°C.
Any unused product or waste material should be disposed of in accordance with local requirements.
LFB Biopharmaceuticals Limited, Suite 104, Spirella Building, Bridge Road, Letchworth Garden City, SG6 4ET
+44(0)1628 531171
+44(0) 1462 558844
+44(0) 1462 558844
+44(0)1628 530559
+44(0)1773 515034
www.lfbbiopharmaceuticals.co.uk
