Novel Drug Brings New Hope for Hemophilia A

Highlights :

• Investigational drug emicizumab via subcutaneous infusion brings relief to those resistant to intravenous drug
• Ninety five percent of children undergoing treatment did not experience any bleeding events.
• The drug also revealed a strong safety profile, with no serious adverse events.

In a phase III trial, the investigational drug, emicizumab proved to be extremely useful via subcutaneous infusion in children who had developed resistance to the traditional intravenous mode. Such children usually develop antibodies or inhibitors which bind to the factor molecules and render it ineffective. Emicizumab has been developed to target such patients.

Emicizumab is a bispecific humanized monoclonal antibody developed to prevent bleeds in patients with hemophilia A with and without inhibitors. It is co-developed by Roche and Genentech. The drug is almost similar to Factor VIII but the structure makes it unrecognizable to Factor VIII antibodies and inhibitors. In earlier trials involving adults and adolescents, emicizumab caused increased bleeding which Dr. Young associates to a bypassing agent (BPA) that they consumed simultaneously.

The present study enrolled 60 children from ages 1-12 years of age who had developed antibodies which prevented effective treatment with Factor VIII. 95% of the children did not experience bleeding after treatment with subcutaneous, once-weekly emicizumab indicating that the drug has been able to prevent bleeding episodes in hemophilia A The drug has also passed the test for safety concerns and adverse events.

In the same field, an earlier study had showed that a single infusion of an investigational gene therapy! enabled production of normal or near-normal levels of Factor VIII. This was the first successful gene therapy indicating such high levels of improvement of FVIII. This normal to near-normal production of FVIII could completely eliminate the need for prophylactic or interventional intravenous FVIII infusions in people with hemophilia.

Weekly subcutaneous emicizumab has the potential to reduce overall treatment and disease burden and may provide a new standard of care for hemophilia management by providing an effective, safe and convenient option for pediatric hemophilia A with inhibitors.

"Before this drug, we didn't have very effective ways to prevent joint bleeding in these patients," said lead study author Guy Young, MD, director of the hemostasis and thrombosis program at Children's Hospital Los Angeles and University of Southern California. "This drug has demonstrated a very high level of efficacy at preventing those bleeding events. It's been life-changing for the children I've treated."

A future trial will determine the safety and efficacy of emicizumab in patients who do not have the inhibitors.With the novel drug, the outlook for hemophilia A is extremely positive and is a huge step in improving the quality of lives of patients globally.

What is Hemophilia A?

Hemophilia A or Factor VIII deficiency is a classic form of hemophilia. It is an X-linked genetic disorder characterized by missing or mutated Factor VIII protein required for clotting. In some cases, spontaneous mutations in the gene cause the disorder. People with hemophilia A are at risk of prolonged bleeding from simple injuries and falls. Internal bleeding also occurs in joints and muscles, stomach and in some cases brain bleeds. Bleeding can be stemmed with immediate infusion of Factor VIII. Currently, the only available treatment for hemophilia A is infusion of external Factor VIII either as a prophylactic or response to bleeding episodes.

References:

1. New Therapies Improve Outlook for Bleeding and Clotting Disorders - (http://www.hematology.org/Newsroom/Press-Releases/2017/8065.aspx)
2. Bleeding Disorder Future Therapies - (https://www.hemophilia.org/Bleeding-Disorders/Future-Therapies)

Source: Medindia