Xyntha (moroctocog alfa) for hemophilia

What is Xyntha for hemophilia?

Xyntha (moroctocog alfa) is a lab-made factor VIII replacement therapy approved to prevent and treat bleeding, including during surgery, in people with hemophilia A.

In hemophilia A, genetic mutations prevent the body from producing enough working factor VIII (FVIII), a protein involved in blood clotting. One treatment strategy is to replace the missing protein with a recombinant, or lab-made, version.

Xyntha is one such recombinant FVIII medication. When injected directly into the bloodstream (intravenously), the treatment can help restore blood-clotting activity to manage bleeding.

Wyeth Pharmaceuticals developed Xyntha before Pfizer acquired the company and took over marketing the therapy. Pfizer also sells Xyntha Solofuse, a version of the medication packaged with a prefilled syringe to streamline preparation and administration.

Therapy snapshot

Brand name	Xyntha
Chemical name	Moroctocog alfa
Usage	Prevention and treatment of bleeding episodes, including those occurring during surgery, in hemophilia A patients
Administration	Intravenous injection

Who can take Xyntha?

In the U.S., regulators have approved Xyntha for hemophilia A patients of any age. The medication works in three ways:

• Routine prophylaxis: regular administration to prevent or reduce the frequency of bleeds
• On-demand: as-needed treatment to control active bleeds
• Perioperative management: prophylactic and ongoing care to prevent and manage bleeds around the time of surgery

The indications are the same for Xyntha Solofuse.

The medication is contraindicated, or should not be used, for patients with known allergies to Xyntha, its ingredients, or hamster proteins, as hamster cells are used during manufacturing.

Xyntha is not approved to treat von Willebrand disease, another type of inherited bleeding disorder.

Xyntha and Xyntha Solofuse are also approved in Canada. In the European Union, a product containing the same active ingredient is approved and sold as Refacto AF for similar indications. However, Xyntha and Refacto AF have different potencies and are not interchangeable.

How is Xyntha administered?

Xyntha is delivered as an intravenous (into-the-vein) injection. After proper training from a healthcare professional, people with hemophilia A and their caregivers may prepare and administer the medication at home.

The dose and administration schedule depend on how patients use the medication:

• Prophylaxis: For people ages 12 and older, the recommended starting dose is 30 international units (IU) per kg of body weight, given three times a week. Younger children typically start at 25 IU/kg every other day. Healthcare providers can adjust these doses based on clinical responses.
• On-demand: Dosing varies depending on the severity and location of bleeding.
• Perioperative: Dosing depends on the type of surgery.

Xyntha comes as a powder in a glass vial, accompanied by a separate syringe containing liquid that users must mix before drawing it into the syringe for injection. Xyntha Solofuse provides the powder medication and liquid in a single two-chamber syringe that allows direct mixing.

In some cases, patients may combine Xyntha vial kits and Xyntha Solofuse syringes to achieve the desired dose. A healthcare provider will provide instructions on how to mix them.

Xyntha in clinical trials

Three main Xyntha clinical trials evaluated the medication in people with hemophilia A. The open-label studies assessed Xyntha for prophylaxis, on-demand treatment, and surgical control in 174 participants. Across studies, the results showed:

• Prophylactic treatment: Annual bleeding rates dropped by 88% for adults and adolescents (94 participants) and 97% for children younger than 12 (eight participants) compared with on-demand treatment alone. In total, 45% of adults and adolescents and 50% of children experienced zero bleeds during the studies.
• On-demand treatment: A total of 187 bleeding episodes in 53 adults and adolescents and 562 episodes in 38 children were treated in the on-demand portions of the studies. One or two injections of Xyntha successfully resolved 93% of bleeds in adults and adolescents and 92% in children.
• Surgical control: Thirty participants received at least one dose of Xyntha to manage bleeding during surgery. Bleeding control was rated as excellent or good across all 25 evaluable bleeds.

Xyntha side effects

The most common side effects of Xyntha observed in clinical trials of patients previously treated with replacement therapies included:

• headache
• joint pain
• fever
• cough

Some people who use Xyntha develop allergic reactions, including a potentially life-threatening reaction called anaphylaxis. If patients experience an itchy rash or hives, wheezing, chest tightness, or low blood pressure, Xyntha should be stopped immediately, and patients should seek medical care.

Additionally, the immune system may develop inhibitors, a type of antibodies that target the FVIII in Xyntha, which can reduce the treatment’s efficacy. If bleeding control is insufficient or the activity of FVIII in the blood is lower than expected, doctors may recommend testing for these inhibitors.

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