Afstyla: The First Single-Chain Factor VIII Therapy for Patients With Hemophilia A

Hemophilia A patients tend to bleed longer than healthy individuals since their body lacks a blood clotting factor called factor VIII (FVIII). If you or your loved one have been experiencing spontaneous and frequent bleeds without any obvious cause, you may want to consider using Afstyla after consulting with your doctor. 

Afstyla is more effective at preventing and treating bleeding episodes in patients with severe hemophilia A than other available clotting factor VIII products. It is the first and only approved single-chain factor VIII therapy by the FDA that provides long-lasting protection from bleeds.

In this article, we will discuss what Afstyla is and how it can help patients with hemophilia A. We will also take a look at its standard dosage and administration process, potential side effects, estimated costs, and much more.

What Is Afstyla, and What Is It Used For?

Afstyla, also known by its generic name, antihemophilic factor (recombinant), single-chain, is a recombinant product that contains a lab-made form of factor VIII protein. This artificial form of factor VIII temporarily replaces the missing coagulation factor VIII and helps to clot blood and stop bleeding in patients with hemophilia A (a bleeding disorder that occurs due to a deficiency of clotting factor VIII protein). Hemophilia A is also known as congenital Factor VIII deficiency.

Afstyla is typically prescribed to adults and children with hemophilia A and is used under the following circumstances:

• To prevent or reduce the frequency of bleeding episodes (used as a prophylactic agent)
• To control active bleeds occurring due to accidental injury/trauma (used as an on-demand treatment)
• To prevent and manage spontaneous bleeds occurring during surgery (perioperative management).

It should be noted that recombinant Afstyla is not approved for use in treating von Willebrand disease. 

How Does Afstyla Work and Help Patients With Hemophilia A?

Afstyla contains an active component, lonoctocog alfa, which is a short version of naturally occurring human clotting factor VIII. 

This active component works like human factor VIII and becomes activated in the bloodstream when bleeding episodes occur. Once activated, Afstyla helps form a clot by working with other proteins in the blood to stop the bleeding. 

Moreover, the single-chain structure of Afstyla is a unique feature that allows the drug to bind more tightly to the von Willebrand factor (VWF). This protein stabilizes factor VIII in the blood for a long period. Hence, by binding to VWF, Afstyla does not break down quickly, stays active longer, and works more effectively than traditional blood clotting factor VIII drugs. 

What Is the Standard Dose of Afstyla for Hemophilia A Patients?

The standard dosage and frequency of Afstyla are determined based on the severity of Factor VIII deficiency, the extent, location, type of bleeding, patient’s clinical condition, and body weight (kg). 

1. Dosage for Routine Prophylaxis 

The recommended dosing range of Afstyla for adults and children (≥12 years of age) is 20 to 50 IU per kg of Afstyla, which should be given 2 to 3 times a week. For children under age 12, a dose of 30 to 50 IU per kg is administered 2 to 3 times a week.

2. Dosage for On-Demand Treatment and Control of Bleeding Episodes

For on-demand treatment, Afstyla is given to maintain the FVIII activity levels within the target range:

• For minor bleeding (e.g., joint bleeds, minor muscle bleeds, or oral bleeding), Afstyla is administered every 12 to 24 hours to achieve FVIII levels of 20 to 40 IU/dL until the bleeding stops. 
• In cases of moderate bleeding (e.g., muscle and joint bleeds or mild trauma), Afstyla is administered every 12 to 24 hours to keep FVIII activity levels between 30 to 60 IU/dL until the issue is resolved. 
• For severe or potentially fatal bleeding (e.g., deep muscle and brain hemorrhages, fractures, or head trauma), Afstyla is administered every 8 to 24 hours to reach FVIII levels of 60 to 100 IU/dL until the bleeding stops.

3. Dosage for Perioperative Management of Bleeding

During minor and major surgical procedures, Afstyla is used to maintain the FVIII activity levels at or above the target range, which are as follows:

• During minor surgical procedures (e.g., tooth extraction), to keep FVIII activity levels between 30 and 60 IU/dL, Afstyla is administered every 24 hours for at least a day until healing is complete. 
• During major surgical procedures (e.g., hip replacement surgery or brain surgery), to keep FVIII activity levels between 80 and 100 IU/dL, Afstyla is administered every 8 to 24 hours until recovery is complete. The treatment should be administered for at least another 7 days to keep FVIII activity levels between 30 and 60 IU/dL.

How Is Afstyla Administered?

Afstyla is administered intravenously (injected into the vein). This drug comes in single-dose vials as a white or slightly yellow dried powder that must be reconstituted (diluted) in sterile water or diluent provided in the kit. The following are the available color-coded dosing strengths of Afstyla:

• Orange: 250 IU per vial
• Blue: 500 IU per vial
• Green: 1,000 IU per vial
• Turquoise: 1,500 IU per vial
• Purple: 2,000 IU per vial
• Cool Grey: 2,500 IU per vial
• Yellow: 3,000 IU per vial

It is recommended to always check the strength of your prescribed dose printed on the label before using it. 

Administration Process

After receiving the appropriate instruction from a qualified healthcare professional, Afstyla can be administered by a caregiver or the patient themselves. Here are some useful tips that can be followed to administer this drug safely. 

• Make sure you follow an aseptic technique when injecting Afstyla to avoid the risk of injection site-related infections. 
• Do not combine Afstyla with other medications.
• Always use intravenous injection to administer Afstyla.
• Afstyla should be administered within 4 hours of reconstitution at room temperature. 
• Afstyla should only be taken once. After administration, properly dispose of all administration supplies and any leftover solution.

Side Effects

Afstyla has fewer side effects compared to other available factor VIII medications. The safety profile of Afstyla was evaluated in one of the largest FVIII clinical trial programs, including 258 Hemophilia A participants. Approximately 14 out of 258 reported the following side effects during clinical trials:

• Allergic (hypersensitivity) reactions (seen in up to 1 in 10 people)
• Dizziness (seen in 0.8% of people)

These side effects are temporary and subside after taking medications prescribed by a healthcare provider. 

What Precautions Should You Take Before Using Afstyla?

Always consult your healthcare provider before using Afstyla if you:

• Are pregnant or planning to become pregnant
• Are breastfeeding
• Have been told you have FVIII inhibitors (because this medicine may not work for you if you have inhibitors to factor VIII)
• Are allergic to hamster proteins (because Afstyla is manufactured using this protein)
• Are using any over-the-counter medications, supplements, or herbal products
• Have or have had any medical problems

Cost

The cost for Afstyla recombinant intravenous powder for injection is around $12 for a supply of 1 powder for injection, depending on the pharmacy you visit.

Conclusion

Afstyla offers long-lasting therapeutic benefits for controlling and preventing frequent bleeding compared to other factor VIII medications. However, it is important to consult your doctor before using Afstyla.