May 25, 2017
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"The US Food and Drug Administration (FDA) has approved antihemophilic factor (recombinant), single chain (rVIII-single chain; Afstyla, CSL Behring) for on-demand treatment and control of bleeding episodes, routine prophylaxis to decrease t"...



(Antihemophilic Factor, Recombinant) for Intravenous Injection


AFSTYLA is a single-chain recombinant Factor VIII produced in chinese hamster ovary (CHO) cells. It is a construct where the B-domain occurring in wild type full-length Factor VIII has been truncated and 4 amino acids of the adjacent acidic a3 domain were removed (amino acids 765 to 1652 of full-length Factor VIII). AFSTYLA is expressed as a singlechain Factor VIII molecule with covalent linkage between heavy and light chains; thereby keeping the molecule in the single chain form resulting in increased stability and increased von Willebrand Factor (VWF) affinity. Except for a new N-glycosylation site at the junction between heavy and light chains, the post-translational modifications are comparable to endogenous Factor VIII.

AFSTYLA is purified by a controlled multi-step process including two virus reduction steps complementing each other in their mode of action. No human or animal derived proteins are used in the purification or formulation processes.

AFSTYLA is a preservative-free, sterile, non-pyrogenic, lyophilized powder to be reconstituted with sterile water for injection (sWFI) for intravenous injection. AFSTYLA is available in single-use vials containing the labeled amount of Factor VIII activity, expressed in IU. Each vial contains nominally 250, 500, 1000, 2000 or 3000 IU of AFSTYLA. The actual potency is labeled on each AFSTYLA vial and carton. After reconstitution of the lyophilized powder, all dosage strengths yield an almost colorless to slightly opalescent solution. The concentrations of excipients based on the vial size, as well as the amount of sWFI for reconstitution are provided in the table below.

Nominal Composition after Reconstitution with sWFI

Ingredient 250 IU vial 500 IU vial 1000 IU vial 2000 IU vial 3000 IU vial
rVIII-Single Chain 100 IU/mL 200 IU/mL 400 IU/mL 400 IU/mL 600 IU/mL
L-Histidine 3.1 mg/mL 3.1 mg/mL 3.1 mg/mL 3.1 mg/mL 3.1 mg/mL
Polysorbate 80 0.2 mg/mL 0.2 mg/mL 0.2 mg/mL 0.2 mg/mL 0.2 mg/mL
Calcium chloride 0.4 mg/mL 0.4 mg/mL 0.4 mg/mL 0.4 mg/mL 0.4 mg/mL
Sodium chloride 16.4 mg/mL 16.4 mg/mL 16.4 mg/mL 16.4 mg/mL 16.4 mg/mL
Sucrose 6 mg/mL 6 mg/mL 6 mg/mL 6 mg/mL 6 mg/mL
Water for Injection 2.5 mL 2.5 mL 2.5 mL 5 mL 5 mL

The number of units of Factor VIII administered is expressed in IU, which are related to the current WHO standard for Factor VIII products. One IU of Factor VIII activity in plasma is equivalent to that quantity of Factor VIII in 1 mL of normal plasma. Factor VIII activity in plasma is expressed either as a percentage (relative to normal human plasma) or in IU (relative to an International Standard for Factor VIII in plasma).

Last reviewed on RxList: 6/2/2016
This monograph has been modified to include the generic and brand name in many instances.

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