Active Ingredient: Efanesoctocog alfa
For this indication, competent medicine agencies globally authorize below treatments:
For:
Intravenous, 50 international units efanesoctocog alfa per kilogram of body weight, one dose.
Individual patients may vary in their response to factor VIII, demonstrating different half-lives and recoveries. Dose based on bodyweight may require adjustment in underweight or overweight patients. Monitoring of factor VIII levels for the purpose of dose adjustment is usually not necessary during routine prophylaxis. In case of major surgery or life-threatening bleeds, determination of factor VIII levels is required to guide the dose and frequency of repeated injections.
When using an in vitro thromboplastin-time (aPTT)-based one-stage clotting assay for determining factor VIII activity in patients' blood samples, plasma factor VIII activity results can be significantly affected by both the type of aPTT reagent and the reference standard used in the assay. Also there can be significant discrepancies between assay results obtained by aPTT-based one-stage clotting assay and the chromogenic assay according to Ph. Eur. This is of importance particularly when changing the laboratory and/or reagents used in the assay.
It is recommended to use a validated one-stage clotting assay to determine plasma factor VIII activity of efanesoctocog alfa. Throughout the clinical development an Actin-FSL-based one-stage clotting assay was used.
According to the findings of a comparative analysis of clinical study samples, results obtained using a chromogenic assay should be divided by 2.5 to approximate the patient’s factor VIII activity. In addition, a field study comparing different aPTT reagents indicated approximately 2.5-fold higher factor VIII activity levels when using Actin-FS instead of Actin-FSL in the one-stage clotting assay and approximately 30% lower results when using SynthASil.
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 IU of factor VIII activity is equivalent to that quantity of factor VIII in one mL of normal human plasma.
For the dose of 50 IU factor VIII per kg body weight, t he expected in vivo plasma recovery in factor VIII level expressed as IU/dL (or % of normal) is estimated using the following formula:
Estimated increment of factor VIII (IU/dL or % of normal) = 50 IU/kg x 2 (IU/dL per IU/kg)
Efanesoctocog alfa dosing for the on-demand treatment, control of bleeding episodes and perioperative management is provided in the following table.
Guide to efanesoctocog alfa dosing for treatment of bleeding episodes and surgery:
| Degree of haemorrhage/Type of surgical procedure | Recommended dose | Additional information |
|---|---|---|
| Haemorrhage | ||
| Single dose of 50 IU/kg | For minor and moderate bleeding episodes occurring within 2 to 3 days after a prophylactic dose, a lower dose of 30 IU/kg dose may be used. An additional dose of 30 or 50 IU/kg after 2 to 3 days may be considered. | |
| More extensive haemarthrosis, muscle bleeding or haematoma | Single dose of 50 IU/kg | Additional doses of 30 or 50 IU/kg every 2 to 3 days may be considered until bleeding is resolved. |
| Life threatening haemorrhages | Single dose of 50 IU/kg | Additional doses of 30 or 50 IU/kg every 2 to 3 days may be administered until the threat is resolved. |
| Surgery | ||
| Minor surgery including tooth extraction | Single dose of 50 IU/kg | An additional dose of 30 or 50 IU/kg after 2 to 3 days may be considered. |
| Major surgery | Single dose of 50 IU/kg | Additional doses of 30 or 50 IU/kg every 2 to 3 days may be administered as clinically needed until adequate wound healing is achieved. |
For resumption of prophylaxis (if applicable) after treatment of a bleed, it is recommended to allow an interval of at least 72 hours between the last 50 IU/kg dose for treatment of a bleed and resuming prophylaxis dosing. Thereafter, prophylaxis can be continued as usual on the patient’s regular dosing schedule.
The entire efanesoctocog alfa dose should be injected intravenously over 1 to 10 minutes, based on the patient’s comfort level.
Liability Disclaimer : RxReasoner has utilized reasonable care in providing content and services that are accurate, complete and up to date. However, RxReasoner does not accept any responsibility or liability about it. The content and services of RxReasoner are for informational purposes only and they are not intended to be a substitute for the knowledge, expertise, skill, and judgment of physicians, pharmacists, nurses, or other healthcare professionals involved in patient care. RxReasoner offers no medical advice. Users are responsible for the use of the provided content. A shown indication or treatment should not be construed to indicate that the medication is safe, appropriate, or effective in any given patient or under any particular circumstances. The absence of an indication or treatment should not roule out the existence of other appropriate medications. Always seek the advice of a physician or other qualified health provider with any questions you may have regarding a medical condition or medicament. RxReasoner is not liable for any damages allegedly sustained arising out of the use of its content and services.
