US Food and Drug Administration (FDA) has granted marketing approval to CSL Behring for RiaSTAP, the first and only treatment of acute bleeding episodes in patients with congenital fibrinogen deficiency, including afibrinogenemia and hypofibrinogenemia.

Congenital fibrinogen deficiency is a rare, potentially life-threatening bleeding disorder that affects an estimated one person per million, with an estimated prevalence in the US of approximately 300 patients. RiaSTAP is not indicated to treat dysfibrinogenemia.

RiaSTAP was granted orphan status in March 2008 and priority review in August 2008. Approval was based on a pivotal phase-II prospective, open-label pharmacokinetic (PK) and safety study using maximum clot firmness (MCF) as a surrogate endpoint for haemostatic efficacy. MCF is a laboratory measure of the structural integrity of the clot, reflecting the underlying effectiveness of the fibrinogen present to form a fibrin clot.

"The FDA approval of RiaSTAP underscores CSL Behring's ongoing commitment to addressing the unmet needs of patients with rare and serious bleeding disorders," said Robert Lefebvre, general manager and vice president of CSL Behring's US Commercial Operations. "As a leader in developing safe, effective and high-quality biologic therapies, CSL Behring is pleased to introduce a product for congenital fibrinogen deficiency that provides a new therapeutic option to support haemostasis and clot stability."

Fibrinogen, also called Factor I (one), is a protein needed to form a blood clot. Fibrinogen levels in plasma determine the potential clotting ability and activity in the body. Diminished concentrations of fibrinogen limit the body's ability to form a clot. Certain fibrinogen levels usually indicate normal blood clotting ability, though in rare instances a person can have a normal quantity of fibrinogen that does not function as needed.

Symptoms of congenital fibrinogen deficiency include excessive bleeding following injury, bruising, bleeding of the umbilical cord at birth and from the site of the umbilical stump in a newborn, spontaneous bleeding and bone, joint or tissue haemorrhage. To determine fibrinogen levels and confirm a diagnosis, blood coagulation testing is needed.

"RiaSTAP marks a significant improvement in the treatment of congenital fibrinogen deficiency," said Dr Marilyn Manco-Johnson, professor of paediatrics and director, Mountain States Regional Haemophilia and Thrombosis Center. "Now patients with this rare bleeding disorder have access to an effective, safe and convenient therapy that has been available in Europe for years. CSL Behring's development of RiaSTAP for the US market exemplifies the company's dedication to and support of the rare bleeding disorder community."

RiaSTAP is a purified fibrinogen concentrate that undergoes virus inactivation and removal for safety assurance. There have been more than 1 million units sold worldwide (marketed outside the U.S. under the trade name Haemocomplettan P).

Results from the 15-patient PK study showed that median fibrinogen plasma antigen levels and median fibrinogen plasma activity levels reached a maximum within 30 minutes (antigen) to 1 hour (activity) post-infusion and decreased continuously afterward. Results also demonstrated a highly significant (p<0.0001) mean improvement in MCF from baseline to 1 hour post-infusion following RiaSTAP treatment.

CSL Behring is studying RiaSTAP in an ongoing post-marketing commitment study to further demonstrate safety and hemostatic efficacy.

RiaSTAP is a purified fibrinogen concentrate indicated for the treatment of acute bleeding episodes in patients with congenital fibrinogen deficiency, including afibrinogenemia and hypofibrinogenemia.

CSL Behring is a global leader in the plasma protein biotherapeutics industry.