Tretten vs Corifact for Factor XIII: What's the Difference?

Getting diagnosed with a rare bleeding disorder like Factor XIII (Factor 13) deficiency can feel overwhelming, especially when faced with new medical terminology and treatment decisions. If you need replacement therapy, your doctor may recommend treatment with either Tretten or Corifact.

The main difference between these two treatments lies in how they are made and which parts of the Factor XIII protein they contain. Tretten is a lab-made (synthetic) treatment that replaces only the “A” part of the Factor XIII protein ^[1], while Corifact is made from human blood plasma and replaces both the “A” and “B” parts of the protein ^[2]. Because of these differences, the specific type of Factor XIII deficiency you have determines which medication is a safe and effective option for you.

Understanding Your Diagnosis: Subunit A vs. Subunit B

Factor XIII is normally found in your blood as a complex made of two parts: Subunit A and Subunit B ^[2][3]. Subunit A is the “active worker” that helps form strong blood clots, while Subunit B acts as a “carrier protein” that stabilizes Subunit A and helps it move safely through your bloodstream ^[4][5].

When you are diagnosed with Factor XIII deficiency, specialized blood work or genetic testing is typically done as a standard part of your diagnosis to show whether you are missing Subunit A or Subunit B. Most people with this condition have a deficiency in Subunit A ^[6][1]. Knowing your specific subtype is critical because it dictates which treatment your body can use.

Tretten: The Recombinant Option

Tretten is a recombinant factor product, which means it is artificially created in a laboratory rather than being drawn from human blood donors ^[3][1]. It is specifically engineered to provide only Subunit A ^[1][2].

Because it lacks Subunit B entirely, Tretten is only approved and effective for patients who have Subunit A deficiency ^[1][3]. If you have a Subunit B deficiency, your body would not have the carrier protein needed to stabilize the synthetic Subunit A provided by Tretten, making it an inappropriate treatment choice. Since Tretten is lab-made, it carries zero risk of transmitting human blood-borne viruses ^[3].

Corifact: The Plasma-Derived Option

Corifact is a plasma-derived concentrate. This means it is purified from the pooled blood plasma of healthy human donors. The manufacturing process includes strict purification and viral inactivation steps to heavily reduce the risk of transmitting infections ^[3][7]. However, because it comes from human blood, a theoretical risk of infection remains.

Unlike Tretten, Corifact contains both Subunit A and Subunit B just as they appear naturally in human blood ^[2][1]. Because it provides both parts of the protein, Corifact can be used to treat patients with either Subunit A or Subunit B deficiency ^[7][2].

How Treatment Looks: Administration and Safety

Both Tretten and Corifact are given directly into the bloodstream as an intravenous (IV) infusion ^[8][1]. They are commonly prescribed for prophylaxis (routine prevention) to stop bleeds before they start, which often involves an infusion around every 28 days, depending on how your body processes the medication ^[8][1]. They can also be used to manage bleeding around the time of surgery ^[8][9]. Over time, many patients or their caregivers learn to safely perform these infusions at home.

Overall, both medications are highly effective and generally well-tolerated, but there are potential side effects to be aware of:

• Allergic reactions: As with any infused protein, there is a risk of allergic reactions, ranging from mild skin rashes to more severe responses during the infusion ^[10].
• Inhibitors: In very rare cases, your immune system might mistake the replacement factor as a foreign threat and develop “inhibitors” (antibodies) that stop the medication from working ^[11][12].
• Blood clots: Since these medications help your blood clot, there is a theoretical risk of blood clots (thrombosis), especially if you have other risk factors ^[13].

Summary of Differences

• Composition: Tretten is lab-made (synthetic) ^[3]. Corifact is derived from human blood plasma ^[7].
• Infection Risk: Tretten carries no human viral risk ^[3]. Corifact carries a very small, theoretical risk despite rigorous safety steps ^[7].
• Subunits included: Tretten contains only Subunit A ^[1]. Corifact contains both Subunit A and Subunit B ^[2].
• Who can take it: Tretten is exclusively for people with Subunit A deficiency ^[1]. Corifact can be taken by people with either Subunit A or Subunit B deficiency ^[7][2].