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International Phase I Trial Results of Recombinant Fusion Protein Linking Coagulation Factor IX With Albumin (rIX-FP) Show All Pharmacokinetic Parameters Significantly Improved in Patients With Severe Hemophilia B

Results from the Phase I of the PROLONG-9FP trial program demonstrate clinical safety and improved pharmacokinetics of rIX-FP compared to current treatment options
ST. GALLEN, Switzerland, Feb. 2, 2012 /PRNewswire/ -- CSL Behring today announced the results of a Phase I study evaluating recombinant fusion protein linking coagulation Factor IX with albumin (rIX-FP) in patients with severe hemophilia B.  Results of the study, which were presented during an oral session at the Gesellscaft fur Thrombose- und Hameostasegorschung (GTH) congress in Switzerland, showed that rIX-FP was well tolerated in all patients and lasted longer in the body, due to its prolonged half-life, compared with current Factor IX treatment options.

CSL Behring, in collaboration with its parent company, CSL Limited (ASX:CSL), is developing rIX-FP for the prophylaxis and treatment of bleeding episodes in patients with congenital Factor IX (FIX) deficiency as part of the PROLONG-9FP clinical study program.

"Hemophilia B is a rare and serious bleeding disorder that prevents normal blood clotting and requires frequent infusion of Factor IX concentrates to restore clotting ability," said Elena Santagostino, M.D., Ph.D., Professor in the Medical School of Clinical and Experimental Hematology at the University of Milan/IRCCS Maggiore Hospital. "The results of this study suggest that rIX-FP is a promising investigational agent for improvement of prophylactic and on-demand treatment for patients with hemophilia B."

In this analysis, no serious adverse events (including no hypersensitivity reactions), presence of inhibitors to Factor IX, or antibodies to rIX-FP were reported.  Terminal half-life (a measure of how long the drug lasts in the body) was more than five-times longer in comparison to values associated with current recombinant FIX therapy. Incremental recovery and area under the curve (a measure of total exposure to the drug) were also significantly improved in comparison to values associated with current recombinant FIX therapy. 

"The development of this new recombinant investigational agent further adds to CSL Behring's long heritage of identifying innovative treatments to improve outcomes for those living with rare bleeding disorders," said Dr. Stefan Schulte, Vice President of Research and Development, CSL Behring. "We look forward to further exploring the potential of rIX-FP in patients with hemophilia B."

CSL Behring and CSL Limited have engineered the rIX-FP albumin fusion protein to extend the half-life of Factor IX while minimizing tolerability issues. In the process, recombinant albumin -- a carrier protein with an inherently long half-life -- is used as a fusion partner.  A specifically designed linker connects the recombinant factor IX and recombinant albumin as a means of optimizing the efficacy of rIX-FP.

About the Phase I Study

The Phase I study, part of the PROLONG-9FP clinical program, was a multi-center, international open-label trial evaluating rIX-FP in patients with documented severe hemophilia B (FIX < or = 2%). The primary objective was to determine the safety of rIX-FP up to 28 days following intravenous injection of 25, 50, or 75 IU/kg.  The secondary objective was to evaluate the pharmacokinetics of rIX-FP.  More information about the study design can be found at

About Hemophilia

Hemophilia is an inherited bleeding disorder characterized by prolonged or spontaneous bleeding, especially into the muscles and joints. In nearly all cases, it affects only males. The disease is caused by deficient or defective blood coagulation proteins known as factor VIII or IX. The most common form of the disease is hemophilia A, or classic hemophilia, in which the clotting factor VIII is either deficient or defective. Hemophilia B is characterized by deficient or defective factor IX. Hemophilia A affects approximately 1 in 5,000 to 10,000 people. Hemophilia B affects approximately 1 in 25,000 to 50,000 people. The recommended treatment for patients who are factor deficient is to treat by replacement factor therapy.

About CSL Behring

CSL Behring is a global leader in the plasma protein biotherapeutics industry. Passionate about improving the quality of patients' lives, CSL Behring manufactures and markets a range of safe and effective plasma-derived and recombinant products and related services. The company's therapies are used in the treatment of immune deficiency disorders, hereditary angioedema, haemophilia, von Willebrand disease, other bleeding disorders and inherited emphysema. Other products are used for the prevention of hemolytic diseases in the newborn, in cardiac surgery, organ transplantation and in the treatment of burns. The company also operates one of the world's largest plasma collection networks, CSL Plasma. CSL Behring is a subsidiary of CSL Limited, a biopharmaceutical company with headquarters in Melbourne, Australia. For more information, visit

Media Contact:
Sheila A. Burke, Director, Communications & Public Relations
Worldwide Commercial Operations
CSL Behring
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Etanjalie Ayala
Weber Shandwick






Posted: February 2012