Kovaltry (octocog alfa), previously known as BAY 81-8973, is a recombinant, or man-made, antihemophilic factor therapy approved to manage the symptoms of hemophilia A in adults and children. It is developed and marketed by Bayer.

In 2016, both the European Commission and the U.S. Food and Drug Administration granted Bayer approvals to market Kovaltry in Europe and the U.S., respectively.

How does Kovaltry work?

Hemophilia A is an inherited bleeding disorder caused by a mutation in the F8 gene, which provides instructions for making a blood clotting protein called factor VIII (FVIII). A deficiency in this protein causes patients to bleed excessively, sometimes for no apparent reason.

Octocog alfa, Kovaltry’s active substance, is a protein engineered to be identical to the natural FVIII found in the body. This is the same active substance used in Bayer’s Kogenate, but it’s produced for this indication using different manufacturing techniques.

Kovaltry is produced using cells from a baby hamster kidney cell line that have been provided with the gene for octocog alfa, along with the human chaperone protein heat shock protein 70 (HSP70). Cells produce the octocog alfa protein, and the HSP70 protein ensures it is correctly folded to work as a functioning protein.

No additional human or animal derivatives are used in the manufacturing process, and Kovaltry is purified in a multistep process, including a dedicated step to remove any viruses.

By replacing the natural FVIII hemophilia A patients are missing, Kovaltry is expected to restore normal blood clotting. The medication is indicated for the treatment and control of bleeds in adults and children with hemophilia A, as well as to manage excessive bleeding during surgery. It also may be used as a routine preventive treatment to lower bleed frequency.

Kovaltry in clinical trials

Kovaltry approvals were supported by data from the LEOPOLD trials, which included LEOPOLD 1 (NCT01029340), LEOPOLD 2 (NCT01233258), and LEOPOLD Kids (NCT01311648). All were Phase 3 trials.

LEOPOLD 1 assessed the safety and efficacy of Kovaltry over a one-year period in 62 men with severe hemophilia A. Patients were randomly assigned a dose between 20 to 50 international units per kg body weight (IU/kg), to be taken two or three times a week. Results confirmed that Kovaltry was safe and effective at preventing and treating bleeds.

The goal of LEOPOLD 2 was to compare Kovaltry as an on-demand treatment or as a prophylactic, or preventive, therapy 80 patients with severe hemophila A. These results demonstrated that prophylactic treatment was significantly more effective than on-demand. Prophylaxis reduced the median annualized bleed rate by 97% compared with on-demand treatment.

As its name suggests, the LEOPOLD Kids trial sought to evaluate the safety and efficacy of Kovaltry as a prophylaxis in children with hemophilia A. Involving 51 patients, ages 1–11, this trial showed Kovaltry was well-tolerated and effective at treating and preventing bleeds.

The safety and efficacy of Kovaltry during surgery also were assessed as part of the LEOPOLD trials. A total of 41 patients — both adults and children — underwent surgery while receiving Kovaltry. Overall, patients did not experience blood loss outside the expected range for surgery. Results demonstrated that Kovaltry can successfully control bleeding during surgery.

Other details

Kovaltry is administered as an intravenous (into-the-vein) injection. It is available in a wide range of strengths: 250, 500, 1,000, 2,000 and 3,000 IU.

The level and frequency of dosage depends on the patient and should be discussed with a healthcare professional. For routine prophylaxis in adults and adolescents, a dosage of 20 to 40 IU/kg two or three times weekly is recommended. Children ages 12 or younger are recommended to take 25 to 50 IU/kg two or three times weekly, or every other day.

The most common side effects associated with Kovaltry include headaches, fever, and rashes. With long-term use, patients may develop neutralizing antibodies, or “inhibitors” against Kovaltry, which can lower its effectiveness.

Kovaltry is contraindicated, or not recommended, in patients who have developed allergies to the active substance, mouse or hamster proteins, or other treatment ingredients.

In case of life-threatening allergic reactions (anaphylaxis), Kovaltry should be stopped immediately and a healthcare professional should be contacted.


Last updated: March 4, 2022, by Teresa Carvalho MS


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