Congenital deficiency of Factor XIII

Dosage

The dosing regimen should be individualised based on body weight, laboratory values, and the patient’s clinical condition.

Routine prophylaxis dosing schedule for treatment of congenital FXIII deficiency

Initial dose

40 International Units (IU) per kg body weight

The injection rate should not exceed 4 ml per minute.

Subsequent dosing

Dosing should be guided by the most recent trough FXIII activity level, with dosing every 28 days (4 weeks) to maintain a trough FXIII activity level of approximately 5 to 20%.

Recommended dosing adjustments of ± 5 IU per kg should be based on trough FXIII activity levels as shown in Table 1 and the patient’s clinical condition.

Dosing adjustments should be made on the basis of a specific, sensitive assay used to determine FXIII levels.

An example of dose adjustment using the standard Berichrom FXIII activity assay is outlined in Table 1 below.

Table 1. Dose adjustment using the Berichrom FXIII activity assay:

The potency expressed in units is determined using the Berichrom FXIII activity assay, referenced to the current International Standard for Blood Coagulation Factor XIII, Plasma. Therefore, a unit is equivalent to an International Unit.

Prophylaxis prior to surgery

After the patient’s last routine prophylactic dose, if a surgery is scheduled:

• Between 21 and 28 days later – administer the patient’s full prophylaxis dose immediately prior to surgery and the next prophylactic dose should be given 28 days later.
• Between 8 and 21 days later – an additional dose (full or partial) may be administered prior to surgery. The dose should be guided by the patient’s FXIII activity levels and clinical condition and should be adjusted according to the half-life of Fibrogammin.
• Within 7 days of last dose – additional dosing may not be needed.

Adjustments to dosing may be different from these recommendations and should be individualised, based on FXIII activity levels and the patient’s clinical condition. All patients should be monitored closely during and after surgery.

It is recommended to monitor the increase in FXIII-activity with a FXIII assay. In the case of major surgery and severe haemorrhage, the aim is to obtain values within the normal range for healthy people, i.e. 0.7-1.4 IU/ml.

Paediatric population

The posology and method of administration in children and adolescents is based on body weight and is therefore generally based on the same guidelines as for adults. The dose and/or frequency of administration for each individual should always be guided by the clinical effectiveness and FXIII activity levels.