Frequently Asked Questions about Helixate® FS
Q. Are there contraindications for Helixate® FS?
A. Known intolerance or allergic reactions to components of Helixate®
FS, or known allergies to hamster and mouse proteins, may be a contraindication
for Helixate® FS. Baby hamster kidney cells are used in the fermentation
[5.2 anchor to fermentation] process to grow the recombinant factor VIII. Mouse
antibody proteins (monoclonal antibody immunoaffinity
chromatography are used in the purification process to remove factor VIII
from the fermentation medium.
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Q. Does Helixate® FS contain albumin?
A. Unlike many other factor VIII concentrates (both plasma-derived and recombinant),
Helixate® FS uses sucrose instead of albumin in the final product
to stabilize the recombinant factor VIII molecule. However, human albumin is needed
to protect and stabilize the recombinant factor VIII protein that is being secreted
by the baby hamster kidney cells in the fermentation medium. Most of the albumin
is removed during the many purification steps, but a minimal amount of albumin (.007
milligrams/mL) does remain in the product. No albumin is added during the purification
or formulation
steps.
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Q. Does the cell culture medium contain any bovine-derived products?
A. The cell culture medium does not contain any proteins derived from animal sources.
For example, bovine insulin has been replaced with recombinant insulin.
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Q. How should Helixate® FS be stored?
A. When stored at refrigerator temperature, 2°–8°C (36°–46°F), Helixate®
FS is stable for the period indicated by the expiration date on the label. Storage
of lyophilized
powder at room temperature (up to 25°C, or 77°F) may be done for twelve months—for
example, in home treatment situations. Avoid freezing. Protect from extreme exposure
to light.
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Q. Is Helixate® FS a recombinant product?
A. Helixate® FS is a recombinant factor VIII product manufactured
using a baby hamster kidney (BHK) cell line. In the purification and formulation
steps for Helixate® FS, the human albumin used as a factor stabilizer
in original Helixate® Antihemophilic Factor (Recombinant) has been
replaced with sucrose; however, a highly purified plasma protein is still used in
the fermentation medium.
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Q. Is Helixate® FS effective?
A. Yes. Helixate® FS has similar biologic activity to original Helixate®
Antihemophilic Factor (Recombinant) and to factor VIII from human plasma. In clinical
studies involving previously treated and untreated patients, respectively, 92.7%
and 88% of the bleeding episodes resolved with one or two treatments of Helixate®
FS.
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Q. Is Helixate® FS safe?
A. Yes. In clinical studies involving previously treated patients, no inhibitor
[5.2 anchor to inhibitor] formation was detected. In clinical studies involving
previously untreated patients, 15% developed inhibitors to Helixate®
FS. In the Joint Outcome Study, which was conducted to demonstrate the effectiveness
of routine prophylaxis for prevention of joint damage in children, the incidence
of new inhibitor development was 12.5%.
The most serious adverse reactions to Helixate® FS are systemic hypersensitivity
reactions and the development of high-titer inhibitors necessitating alternative
treatments to antihemophilic factor. The most common adverse reactions observed
in clinical trials were inhibitor formation in previously untreated or minimally
treated patients, skin-associated hypersensitivity reactions, infusion site reactions,
and central venous access device (CVAD) line-associated infections.
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Q. Is Helixate® FS virally inactivated?
A. Helixate® FS uses a solvent/detergent process designed to help
eliminate lipid-enveloped viruses [5.2 anchor to enveloped viruses] (such as HIV,
hepatitis B and C, and herpes). Helixate® FS also uses the patented
monoclonal antibody (MAb) immunoaffinity chromatography purification process designed
to help eliminate viruses. In this process, antibodies specific to a single target
protein (such as factor VIII) are placed in a chromatography column. When the solution
is passed through the column, the antibodies bind the target protein.
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Q. How soon after reconstitution must Helixate® FS be administered?
A. Because there is no preservative in the product, Helixate® FS
should be administered within three hours of reconstitution.
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Q. Other than sucrose, what is the purpose of the other excipients in the final
formulation of Helixate® FS?
A. Helixate® FS is lyophilized, which means it is rapidly freeze-dried
under high vacuum. When a solution is freeze-dried, crystals form. The sodium, chloride,
and calcium chloride protect the product during the freeze-drying process, while
the glycine and histidine stabilize the crystal matrix.
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Q. Is Helixate FS indicated for Prophylaxis?
A. Helixate® FS is indicated for routine prophylaxis in children
with hemophilia A with no pre-existing joint damage. Helixate® FS
was approved for this indication on July 30, 2009.
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Q. Which clinical trial demonstrated adequate efficacy for Helixate®
FS in a prophylactic regimen?
A. This indication was granted by the FDA based on data from a multicenter, randomized,
open-label trial was conducted in 65 boys with severe hemophilia A between April
1996 and April 2005. The results of this trial have been published in The New England
Journal of Medicine under the title "Prophylaxis versus Episodic Treatment
to Prevent Joint Disease in Boys with Severe Hemophilia" Marilyn J. Manco-Johnson,
M.D., Thomas C. Abshire, M.D. et al.
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Q. Are all factor concentrates indicated for prophylaxis?
A. No, not all factor concentrates are indicated for prophylactic use. Read the
indications section in the package insert of the product in use to find out whether
the product is indicated for prophylaxis
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Q. What dosage strengths is Helixate FS available in?
A. Helixate FS is available in the following dosage strengths:
- 250 IU/2.5-mL diluent**
- 500 IU/2.5-mL diluent**
- 1000 IU/2.5-mL diluent**
- 2000 IU/5.0-mL diluent
- 3000 IU/5.0-mL diluent
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