- Hemophilia A is characterized by
severe bleeding; current standard treatment for the condition
requires intravenous administration of clotting factor two or three times
- Prolonged administration of clotting factor can
result in the development of antibodies (called inhibitors) that attack
and destroy them
- A new therapy involving Emicizumab could prevent
bleeding episodes in hemophilia patients with inhibitors, according to a
phase II clinical trial
A novel therapy called Emicizumab can reduce the incidence
of bleeding episodes by 87 percent in patients with hemophilia A inhibitors,
finds a Phase II clinical trial.
Patients with hemophilia A
-- caused by deficiency of coagulation
factor VIII -- often experience excessive bleeding in the event of a cut or injury and require prophylactic
treatment with intravenously administered factor VIII three times a week.
However, repeated administration of clotting factor can increase the
development of antibodies called inhibitors
. These inhibitors attack and
destroy the necessary factor that affects the treatment.
‘Emicizumab could be a novel therapy for hemophilia A patients who no longer respond to conventional clotting therapies.’
Medications called 'by-passing
are the standard treatment for patients with hemophilia A and
Dr Guy Young,
MD, director of the Hemostasis and Thrombosis Program and lead physician for
study efforts at Children's Hospital Los Angeles, said,
"While the standard medications allow us to 'bypass' the need for Factor VIII,
they don't do the job as efficiently or as well for these patients. 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 three years
because of joint damage from repeated bleeding incidents. Now, he's
Hemophilia Patients with Emicizumab
is a bispecific monoclonal antibody
phase I study, emicizumab markedly reduced the rate of bleeding among patients
with hemophilia A with or without inhibitors.
The phase III
study called HAVEN 1 was conducted by an international team of
hematologists. The research team recruited 109 males, 12 years and older with
hemophilia A with inhibitors. The participants were randomly divided into three
The first group treated with
Emicizumab prophylaxis experienced 87 percent lesser
bleeds when compared to the group that did not receive any prophylactic
The third group comprised of participants who
had previously received prophylactic treatment with bypassing agents and were
now assigned to Emicizumab prophylaxis. The
third group experienced 79 percent fewer bleeds compared to
prior prophylactic by-passing agents.
Benefits of Emicizumab
- Emicizumab is more effective at preventing severe
bleeding in hemophilia A patients
- It has an improved safety profile,
according to the study (no anti-drug antibodies were detected)
- Compared to by-passing agents, Emicizumab is easier
to administer (subcutaneous) and requires only a once a week dosage
the most significant advancement I have seen during my 20 years working in the
field of hemophilia," said Young, who is also a professor of Pediatrics at
the Keck School of Medicine of USC and treats the most pediatric patients with
hemophilia in California. "We've had families flying in from all over the
country to get access to this medication."
The research team plans to
investigate the use of emicizumab in hemophilia A patients without inhibitors.
Currently, Emicizumab is only available to patients as part of the clinical
trial while the Food and Drug Administration (FDA) is
in the process of evaluating the drug.
The study published in
the New England Journal of Medicine
was presented at
the International Society of Thrombosis and Hemostasis.
Hemophilia A is
also known as factor VIII (FVIII) deficiency, which is caused by a defective or missing factor VIII, a clotting protein. Hemophilia
occurs in 1 in 5,000 live births. It is a genetic disorder passed down from
parents to children. However, one-third of hemophilia cases are caused by a
The standard treatment for
hemophilia A is prophylactic intravenous infusions of factor VIII two to three
times a week to prevent severe bleeding. Hemophilia A is four
times more common than hemophilia
. Most of the patients with hemophilia A experience severe bleeding
in case of a cut or injury.
- Gallia G. Levy et al. Emicizumab Prophylaxis in Hemophilia A with Inhibitors. New England Journal of Medicine (2017). DOI: 10.1056/NEJMoa1703068
- Hemophilia A - (https://www.hemophilia.org/Bleeding-Disorders/Types-of-Bleeding-Disorders/Hemophilia-A)