Treatment of von Willebrand disease (VWD) should be supervised by a physician experienced in the treatment of haemostatic disorders.
Posology
Dose and frequency of administration must be individualized according to clinical judgement and based on the patient´s weight, type and severity of the bleeding episodes/surgical intervention and based on monitoring of appropriate clinical and laboratory measures. Dose based on bodyweight may require adjustment in underweight or overweight patients.
Generally, 1 IU/kg (VWF:RCo/VEYVONDI/vonicog alfa) raises the plasma VWF:RCo by 0.02 IU/mL (2%).
Haemostasis cannot be ensured until factor VIII coagulant activity (FVIII:C) is at least 0.4 IU/mL (≥ 40% of normal activity). Depending on the patient's baseline FVIII:C levels, a single infusion of rVWF will, in a majority of patients, lead to an increase above 40% in endogenous FVIII:C activity within 6 hours and will result in sustaining this level up to 72 hours post infusion. The dose and duration of the treatment depend on the clinical status of the patient, the type and severity of the bleeding, and both VWF:RCo and FVIII:C levels. If the patient's baseline plasma FVIII:C level is < 40% or is unknown and in all situations where a rapid correction of haemostasis should be achieved, such as treatment of an acute haemorrhage, severe trauma or emergency surgery, it is necessary to administer a recombinant factor VIII product with the first infusion of VEYVONDI, in order to achieve a haemostatic plasma level of FVIII:C.
However, if an immediate rise in FVIII:C is not necessary, or if the baseline FVIII:C level is sufficient to ensure haemostasis, the physician may decide to omit the co-administration of rFVIII at the first infusion with VEYVONDI.
In case of major bleeding events or major surgeries requiring repeated, frequent infusions, monitoring of FVIII:C levels is recommended, to decide if rFVIII is required for subsequent infusions to avoid excessive rise of FVIII:C.
Treatment of bleeding episodes (on-demand treatment) in adults and children
Start of treatment
The first dose of VEYVONDI should be 40 to 80 IU/kg body weight. Replacement levels of VWF:RCo > 0.6 IU/mL (60%) and FVIII:C > 0.4 IU/mL (40%) should be achieved. Dosing guidelines for treatment of minor and major haemorrhages are provided in Table 1.
VEYVONDI should be administered with recombinant factor VIII if the FVIII:C levels are < 40%, or are unknown, to control bleeding. The rFVIII dose should be calculated according to the difference between the patient's baseline plasma FVIII:C level, and the desired peak FVIII:C level to achieve an appropriate plasma FVIII:C level based on the approximate mean recovery of 0.02 (IU/mL)/(IU/kg). The complete dose of VEYVONDI should be administered followed by rFVIII within 10 minutes.
Calculating dose
VEYVONDI dose [IU] = dose [IU/kg] x body weight [kg]
Subsequent infusions
A subsequent dose of 40 IU to 60 IU/kg of VEYVONDI should be infused every 8 to 24 hours as per the dosing ranges in Table 1, or as long as clinically appropriate. In major bleeding episodes, maintain trough levels of VWF:RCo greater than 50% for as long as deemed necessary.
Based on experience from clinical trials, once VWF has been replaced, endogenous FVIII levels will remain normal or near normal as long as VEYVONDI is continued to be administered.
| Table 1. Dosing recommendations for the treatment of minor and major haemorrhages |
| Haemorrhage | Initial dosea (IU VWF:RCo/kg body weight) | Subsequent dose |
| Minor (e.g. epistaxis, oral bleeding, menorrhagia) | 40 to 50 IU/kg | 40 to 50 IU/kg every 8 to 24 hours (or as long as deemed clinically necessary) |
| Majorb (e.g. severe or refractory epistaxis, menorrhagia, gastrointestinal bleeding, central nervous system trauma, haemarthrosis, or traumatic haemorrhage) | 50 to 80 IU/kg | 40 to 60 IU/kg every 8 to 24 hours for approximately 2-3 days (or as long as deemed clinically necessary) |
| a If rFVIII is administered, see rFVIII package insert for reconstitution and administration instructions. b A bleed could be considered major if red blood cell transfusion is either required or potentially indicated or if bleeding occurs in a critical anatomical site (e.g., intracranial or gastrointestinal haemorrhage). |
Prevention of bleeding/haemorrhage and treatment in case of elective surgery in adults
Prior to surgery
In patients with inadequate levels of FVIII, a dose of 40-60 IU/kg VEYVONDI should be administered 12-24 hours prior to initiating elective surgery (pre-operative dose), to ensure pre-operative endogenous FVIII levels of at least 0.4 IU/mL for minor and at least 0.8 IU/mL for major surgery.
For prevention of excessive bleeding in case of elective surgery, within 3 hours prior to initiation of any surgical procedure, the FVIII:C levels should be assessed. If the FVIII:C levels are at the recommended target level of:
- at least 0.4 IU/mL for minor and oral surgery and
- at least 0.8 IU/mL for major surgery,
a dose of VEYVONDI alone should be administered within 1 hour prior to the procedure.
If the FVIII:C levels are not at the recommended target levels, rFVIII should be administered in addition to vonicog alfa to raise VWF:RCo and FVIII:C, within 1 hour prior to the procedure. Please refer to Table 2 for FVIII:C recommended target levels. The dose depends on VWF and FVIII levels of the patient, the type and severity of the expected bleeding.
| Table 2. Recommended target peak plasma levels of VWF:RCo and FVIII:C to be achieved prior to surgery for the prevention of excessive bleeding during and after surgery |
| Type of surgery | VWF:RCo target peak plasma level | FVIII:C target peak plasma levela | Calculation of rVWF dose (to be administered within 1 hour prior to surgery) (IU VWF:RCo required) |
| Minor | 0.50 – 0.60 IU/mL | 0.40 – 0.50 IU/mL | ∆b VWF:RCo x BW (kg) /IRc |
| Major | 1 IU/mL | 0.80 - 1 IU/mL | ∆b VWF:RCo x BW (kg) /IRc |
| a Additional rFVIII may be required to attain the recommended FVIII:C target peak plasma levels. Dosing guidance should be done based on the IR. b ∆ = Target peak plasma VWF:RCo – baseline plasma VWF:RCo c IR = Incremental Recovery as measured in the subject. If the IR is not available, assume an IR of 0.02 IU/mL per IU/kg. |
During and after surgery
After the initiation of the surgical procedure, the VWF:RCo and FVIII:C plasma levels should be monitored and the intra- and post-operative substitution regimen should be individualised according to the pharmacokinetics (PK) results, intensity and duration of the haemostatic challenge, and the institution's standard of care. In general, the frequency of VEYVONDI dosing for post-operative substitution should range from twice a day to every 48 hours. Please refer to Table 3 for treatment recommendations for subsequent maintenance doses.
| Table 3. Recommended target trough plasma levels of VWF:RCo and FVIII:C and minimum duration of treatment for subsequent maintenance doses for the prevention of excessive bleeding after surgery |
| Type of surgery | VWF:RCo target trough plasma level | FVIII:C target trough plasma level | Minimum duration of treatment | Frequency of dosing |
| Up to 72 hours post surgery | After 72 hours post surgery | Up to 72 hours post surgery | After 72 hours post surgery |
| Minor | ≥ 0.30 IU/mL | - | > 0.40 IU/mL - | | 48 hours | Every 12-24 hrs / every other day |
| Major | > 0.50 IU/mL | > 0.30 IU/mL | > 0.50 IU/mL | > 0.40 IU/mL | 72 hours | Every 12-24 hrs / every other day |
Prophylactic treatment in adults
For initiation of long-term prophylaxis against bleeds in patients with VWD, doses of 40 to 60 IU/kg of VEYVONDI administered twice weekly should be considered. Depending on the patient's condition and clinical response, including breakthrough bleeds, higher doses (not exceeding 80 IU/kg) and/or an increased dose frequency (up to three times per week) may be required.
Paediatric population
The safety and efficacy of VEYVONDI in children aged less than 18 years have been established for the treatment of haemorrhage. Dosing is based on the same guidelines 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 (see section 5.2). The safety and efficacy of VEYVONDI for prophylactic treatment or the prevention or treatment of surgical bleeding have not yet been established in children aged less than 18 years.
Method of administration
VEYVONDI is for intravenous use. The reconstituted product should be inspected visually prior to administration.
The rate of administration should be slow enough to ensure the comfort of the patient, up to a maximum of 4 mL/min. The patient should be observed for any immediate reaction. If any reaction, such as tachycardia, occurs that might be related to the administration of the product, the rate of infusion should be reduced or stopped as required by the clinical condition of the patient.
For instructions on reconstitution of the medicinal product before administration, see section 6.6.