Dosing Kogenate® FS
Kogenate® FS, Antihemophilic Factor (Recombinant) treatment offers an extra margin of confidence, made possible with a sucrose formulation—all in a safe dose. Developed and manufactured exclusively by Bayer HealthCare, Kogenate FS treatment is a prime example of our continued investment in the advancement of hemophilia A treatment.
General Approach to Treatment and Assessment of Treatment Efficacy
These dosing guidelines are presented as general guidance. It should be emphasized that the dosage of Kogenate FS required for hemostasis must be individualized according to the needs of the patient, the severity of the deficiency, the severity of the hemorrhage, the presence of inhibitors, and the FVIII level desired. It is often critical to follow the course of therapy with FVIII level assays. The clinical effect of FVIII is the most important element in evaluating the effectiveness of treatment. It may be necessary to administer more FVIII than estimated in order to attain satisfactory clinical results. If the calculated dose fails to attain the expected FVIII levels, or if bleeding is not controlled after administration of the calculated dosage, the presence of a circulating inhibitor in the patient should be suspected. Its presence should be substantiated and the inhibitor level quantitated by appropriate laboratory tests. When an inhibitor is present, the dosage requirement for FVIII could be extremely variable among different patients, and the optimal treatment can be determined only by the clinical response.
Some patients with low-titer inhibitors (<10 BU) can be successfully treated with FVIII preparations without a resultant anamnestic rise in inhibitor titer.1 FVIII levels and clinical response to treatment must be assessed to insure adequate response. Use of alternative treatment products, such as Factor IX Complex concentrates, Antihemophilic Factor (Porcine), recombinant Factor VIIa or Anti-Inhibitor Coagulant Complex, may be necessary for patients with anamnestic responses to FVIII treatment and/or high-titer inhibitors.
Calculation of Dosage
The in vivo percent elevation in FVIII level can be estimated by multiplying the dose of Kogenate FS Antihemophilic Factor (Recombinant) per kilogram of body weight (IU/kg) by 2% per IU per kg. This method of calculation is based on clinical findings with the use of plasma-derived and recombinant AHF products and is illustrated in the following examples:
The dosage necessary to achieve hemostasis depends upon the type and severity of the bleeding episode, according to the following general guidelines:
| Hemorrhagic event | Therapeutically necessary plasma level of FVIII activity | Dosage necessary to maintain the therapeutic plasma level |
|---|---|---|
| Minor hemorrhage (early hemarthrosis, minor muscle or oral bleeds) |
20–40% | 10–20 IU per kg. Repeat dose if evidence of further bleeding. |
| Moderate to major hemorrhage (hemorrhages into muscles, hemorrhages into the oral cavity, definite hemarthroses, known trauma) Surgery (including tooth extraction) |
30–60% | 15–30 IU per kg. Repeat one does every 12-24 hours until bleeding is resolved. |
| Major to life-threatening hemorrhage (intracranial, intraabdominal or intrathoracic hemorrhages, gastrointestinal bleeding, central nervous system bleeding, bleeding in the retropharyngeal or retroperitoneal spaces, or iliopsoas sheath) Fractures Head trauma |
80–100% | Initial dose 40–50 IU per kg Repeat does 20-25 IU every 8-12 hours until bleeding is resolved. |
| Surgery Major surgical procedures |
100% | Preoperative dose 50 IU/kg Verify 100% activity prior to surgery. Repeat as necessary after 6 to 12 hours initially, and for 10 to 14 days until healing is complete. |
References:
- Kasper CK: Complications of hemophilia A treatment: factor VIII inhibitors. Ann NY Acad Sci 1991; 614:97-105.
