Treatment should be under the supervision of a physician experienced in the treatment of coagulation disorders. The product is of single use and the full content of the vial should be administered. In case any content remains, it should be disposed of in accordance with local requirements.
Von Willebrand disease (VWD)
The ratio between VWF:RCo and FVIII:C is 1:1. Generally, 1 IU/kg BW VWF:RCo and FVIII:C raises the plasma level by 1.5-2% of normal activity for the respective protein.
Levels of VWF:RCo of > 0.6 IU/ml (60%) and of FVIII:C of > 0.4 IU/ml (40%) should be achieved.
Usually, about 20 to 50 IU Wilate/kg BW are necessary to achieve adequate haemostasis.
An initial dose of 50 to 80 IU Wilate/kg may be required, especially in patients with VWD type 3, where the maintenance of adequate plasma levels may require higher doses than in other types of VWD.
For prevention of bleeding in case of surgery, Wilate should be given 1-2 hours before start of the surgical procedure. Levels of VWF:RCo of ≥ 60 IU/dl (≥ 60%) and FVIII:C levels of ≥ 40 IU/dl (≥ 40%) should be achieved.
An appropriate dose should be re-administered every 12-24 hours of treatment. The dose and duration of the treatment depend on the clinical status of the patient, the type and severity of bleeding, and both VWF:RCo and FVIII:C levels.
In patients receiving FVIII-containing VWF products, plasma levels of FVIII:C should be monitored to reveal sustained excessive FVIII:C plasma levels, which may increase the risk of thrombotic events, particularly in patients with known clinical or laboratory risk factors. In case excessive FVIII:C plasma levels are observed, reduced doses and/or prolongation of the dose interval or the use of VWF product containing a low level of FVIII should be considered.
Prophylaxis:
For long term prophylaxis against bleeds in VWD patients, doses of 20-40 IU/kg should be administered 2 or 3 times per week. In some cases, such as in patients with gastrointestinal bleeds, higher doses may be necessary.
Paediatric population
Wilate can be used in children of all ages. Dosing is based on the same guidance as for adults and should be adjusted to the clinical condition of the patient, as well as their VWF:RCo and FVIII:C plasma levels. In younger patients, shorter dose intervals or higher doses may be necessary due to lower recovery and shorter half-life compared to adults (see Section 5.2). For the treatment of haemorrhage in children <6 years of age, initial doses of 50 to 80 IU/kg and maintenance doses of 30 to 50 IU/kg are recommended. For initiation of long-term prophylaxis against bleeds in children <6 years of age, doses of 30 to 50 IU/kg administered 2 or 3 times per week should be considered.
Haemophilia A
Treatment monitoring
During the course of treatment, appropriate determination of factor VIII levels is advised to guide the dose to be administered and the frequency of repeated infusions. Individual patients may vary in their response to factor VIII treatment, demonstrating different half‑lives and recoveries. Dose based on bodyweight may require adjustment in underweight or overweight patients. In the case of major surgical interventions in particular, precise monitoring of the substitution therapy by means of coagulation analysis (plasma factor VIII activity) is indispensable.
Posology
The dose and duration of the substitution therapy depend on the severity of the factor VIII deficiency, on the location and extent of the bleeding and on the patient's clinical condition.
The number of units of factor VIII administered is expressed in International Units (IU), which are related to the current WHO concentrate standard for factor VIII products. Factor VIII activity in plasma is expressed either as a percentage (relative to normal human plasma) or preferably in International Units (relative to an International Standard for factor VIII in plasma).
One International Unit (IU) of factor VIII activity is equivalent to that quantity of factor VIII in one ml of normal human plasma.
On demand treatment:
The calculation of the required dose of factor VIII is based on the empirical finding that 1 International Unit (IU) factor VIII per kg body weight raises the plasma level by 1.5 to 2% of normal activity. The required dose is determined using the following formula:
Required units = body weight (kg) x desired factor VIII rise (%) (IU/dl) x 0.5 IU/kg
The amount to be administered and the frequency of administration should always be oriented to the clinical effectiveness in the individual case. In the case of the following haemorrhagic events, the factor VIII activity should not fall below the given plasma activity level (in % of normal or IU/dl) in the corresponding period.
The following table can be used to guide dosing in bleeding episodes and surgery:
| Degree of haemorrhage/Type of surgical procedure | Factor VIII level required (%) (IU/dl) | Frequency of doses (hours)/Duration of therapy (days) |
| Haemorrhage | | |
| Early haemarthrosis, muscle bleeding or oral bleeding | 20 – 40 | Repeat every 12 to 24 hours. At least 1 day, until the bleeding episode as indicated by pain is resolved or healing is achieved. |
| More extensive haemarthrosis, muscle bleeding or haematoma | 30 – 60 | Repeat infusion every 12 to 24 hours for 3 to 4 days or more until pain and acute disability are resolved. |
| Life threatening haemorrhages | 60 – 100 | Repeat infusion every 8 to 24 hours until threat is resolved. |
| Surgery | | |
| Minor surgery including tooth extraction | 30 – 60 | Every 24 hours, at least 1 day, until healing is achieved. |
| Major surgery | 80 – 100 (pre‑ and postoperative) | Repeat infusion every 8 to 24 hours until adequate wound healing, then therapy for at least another 7 days to maintain a factor VIII activity of 30% to 60% (IU/dl). |
Prophylaxis:
For long-term prophylaxis against bleedings in patients with severe haemophilia A, the usual doses are 20 to 40 IU of factor VIII per kg body weight at intervals of 2 to 3 days. In some cases, especially in younger patients, shorter dosage intervals or higher doses may be necessary.
Continuous infusion:
Prior to surgery, a pharmacokinetic analysis should be performed to obtain an estimate of clearance. The initial infusion rate can be calculated as follows:
Infusion rate (IU/kg/hr) = clearance (mL/kg/hr) x desired steady state level (IU/mL)
After the initial 24 hours of continuous infusion, the clearance should be calculated again every day using the steady state equation with the measured level and the known rate of infusion.
Paediatric population
There are insufficient data to recommend the use of Wilate in haemophilia A in children less than 6 years old.
Method of administration
Intravenous use.
The injection or infusion rate should not exceed 2-3 ml per minute. For children weighing between 6 kg to less than 10 kg, the infusion rate should not exceed 2 ml per minute. For children weighing less than 6 kg, the infusion rate should not exceed 1 ml per minute.
For instructions on reconstitution of the medicinal product before administration, see section 6.6.