According to a story from MD Edge, a phase 2 clinical trial testing the drug concizumab as a treatment for hemophilia A and hemophilia B demonstrated substantial capability in reducing bleeding events. Concizumab inhibits the tissue factor 4 pathway. These trial results were first presented at the congress of the International Society on Thrombosis and Haemostasis. These trials were phase 2 studies that escalated in dosage.
Hemophilia is a genetic disorder which affects the ability of the blood to form clots, a process that is vital for stopping bleeding after a wound is sustained. The severity of symptoms can vary widely. The disorder is caused by a mutation found on the X chromosome. Symptoms include bleeding for a long time after an injury, risk of bleeding in the brain and joints, and easy bruising. Bleeding in the joints can cause permanent damage and brain bleeding can lead to headaches, decreased consciousness, and seizures. There are multiple types of hemophilia, with the most common types being type A and type B, which are distinguished by having deficiencies in different clotting factors. Treatment involves replacing the missing clotting factor. Drugs that thin the blood should be avoided. To learn more about hemophilia, click here.
In these trials concizumab, which is a monoclonal antibody, was delivered subcutaneously (under the skin) once a day. The first trial involved 36 adult patients with hemophilia A that was considered severe. The starting dose was 0.15 mg/kg; patients were upped to 20 mg/kg if they experienced three or more bleeds; if the same number of bleeds was experienced at this level, then the patient was upped to 25 mg/kg. These patients were not using other inhibitors.
The second trial included 16 hemophilia A patients and 10 patients with hemophilia B. All patients were adults. These patients were treated with either a placebo or a 15 mg/kg dose of concizumab. The dose escalation rules in this study were identical to the first. These patients were receiving treatment with other inhibitors. Both studies also had a 24 week initial treatment period that was then extended by at least 52 weeks.
Both groups saw considerable reductions in bleeds. As an example the mean yearly bleeding rate declined from 20.4 to 4.5 bleeds for patients with either type of hemophilia when using other inhibitors. The drug has earned Breakthrough Therapy designation for the treatment of hemophilia B with inhibitors.
Check out the original study here.