Hemophilia A Drug Reduces Number of Bleeding Episodes by Nearly 90%

Emicizumab is administered subcutaneously only once per week compared with clotting factors administered intravenously 3 times per week.

Emicizumab decreases incidence of bleeding episodes by nearly 90% in patients with hemophilia A with inhibitors, according to a study published in the New England Journal of Medicine.

The standard treatment for hemophilia A is prophylactic therapy, which requires frequent injections to prevent bleeds. Unfortunately, repeated administration of clotting factor can result in the development of inhibitors that attack and destroy Factor VIII.

“While the standard medications allow up to ‘bypass’ the need for Factor VIII, they don’t do the job as efficiently or as well for these patients,” Guy Young, MD, lead physician for study efforts at the Children’s Hospital Los Angeles, said in a press release. “Bleeding is harder to stop, and episodes last longer and do more damage to the patients. A patient treated with this new therapy had been in a wheelchair for 3 years because of joint damage from repeated bleeding incidents. Now, he’s walking.”

The investigational drug is a bispecific monoclonal antibody designed to bring together factor IXa and X proteins, which are needed to activate the natural coagulation cascade and restore the blood clotting process.

“This is a breakthrough for individuals with hemophilia A who no longer respond to conventional clotting therapies,” said investigator Alan S. Wayne, MD. “The standard treatment for patients with hemophilia A and inhibitors had been to use medications called ‘bypassing agents’. This new therapy is dramatically more effective at preventing bleeding. Additionally, in comparison to bypassing agents, emicizumab is easier to administer, requires less frequent dosing, and based on this study, appears to have an improved safety profile.”

Included in the phase 3 HAVEN 1 study were 109 males, 12 years or older with hemophilia A with inhibitors. Patients administered emicizumab prophylaxis experienced 87% fewer bleeds compared with patients treated with on-demand bypassing agents and 79% fewer bleeds compared with patients who received prior prophylactic bypassing agents.

“This is the most significant advancement I have seen during my 20 years working in the field of hemophilia,” added Dr Young, who treats most pediatric patients with hemophilia in California. “We’ve had families flying in from all over the country to get access to this medication.”

Hemophilia A occurs in 1 of 5000 live male births, and is approximately 4 times as common as hemophilia B. An estimated 20,000 individuals are living with hemophilia in the United States, according to the National Hemophilia Foundation.