Hybrid Protein Increases Factor IX Life in Hemophilia B Patients

February 12, 2014
Hemophilia Reports, January 2014, Volume 1, Issue 1

Hemophilia B patients treated with a new hybrid protein experience more effective coagulation that requires fewer injections.

A study from UC Davis researchers confirms that new coagulation factor rFIXFc reduces the frequency of injections needed to maintain effective clotting for hemophilia B patients. The factor fuses clotting factor IX with an antibody molecule, which prevents the body from too rapidly metabolizing the protein. Instead of being administered every other or every third day, the new recombinant protein can be administered once a week or even once every two weeks. By fusing the factor IX to an antibody, it allows the hybrid protein to escape the lysosomes, which break down proteins and other molecules. This provides coagulation for hemophilia B patients for an extended period of time.

Hemophilia B is a congenital disorder that nearly always affects men, caused by reduced levels of clotting factor IX, which is essential in the coagulation of blood. The most common form of the disease is hemophilia A, which is categorized by reduced levels of factor VIII.

The trial involved 123 patients aged 12 and up, who were previously treated for hemophilia B. The first group received weekly injections, the second received injections every 10 days, the third was only treated for specific bleeding events, and the last group focused on how patients bled during surgeries. The first group’s annualized bleeding rate was reduced by 83% and the second group saw a 87% decrease, compared to the episodic treatment of group 3. In group 4, there were 14 overall surgeries, where bleeding was categorized as well-controlled.

“This is the first modification to coagulation factors to increase the half-life,” Jerry Powell, MD, director of the UC Davis Hemophilia and Thrombosis Center said in a statement. “My hope is that other pharmaceutical companies will focus on developing additional long-lasting factors to treat other types of hemophilia.”