CSL Behring announced that it has been granted Orphan Drug Designations (ODD) by the European Commission for the development of its recombinant fusion protein linking coagulation factor VIIa with albumin (rVIIa-FP), a novel therapy to treat haemophilia A and haemophilia B patients with inhibitors. The designations would entitle CSL Behring to exclusively market recombinant factor VIIa fused with albumin in Europe for a period of 10 years if the product at the stage of license application fulfils the orphan drug requirements. Based on the submission of data from the company's Paediatric Investigation Plan, once available, the 10-year market exclusivity may be extended to 12 years.

Under these designations European Medicines Agency (EMA) will also provide CSL Behring with development assistance and with reductions in certain regulatory fees.

“CSL Behring welcomes Orphan Drug Designation for rVIIa-FP as support of our ongoing commitment to developing, manufacturing and marketing products for the treatment of rare and serious diseases, such as haemophilia with inhibitors,” said Val Romberg, senior vice president, Global Research & Development. “We will continue to work closely with the EMA to make this important therapy available to patients as soon as possible.”

An orphan drug designation application has not yet been submitted in the United States.

By providing incentives to the pharmaceutical industry, the EU legislative framework for orphan medicines encourages the development of products intended to diagnose, prevent and treat life-threatening or chronically-debilitating conditions that impact up to 5 in 10,000 people in the European Union. The initiative helps improve access to quality medical care for patients who have rare diseases for which there are few, if any, approved treatments.

Haemophilia is an inherited bleeding disorder characterized by prolonged or spontaneous bleeding, especially into the muscles, joints, or internal organs. 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 haemophilia A, or classic haemophilia, in which the clotting factor VIII is either deficient or defective. Haemophilia B is characterized by deficient or defective factor IX. Haemophilia A affects approximately 1 in 5,000 to 10,000 people. Haemophilia 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.

Some patients develop inhibitors, factor VIII or IX neutralizing antibodies which render further replacement therapy ineffective. It has been reported that up to 33% of all severe haemophilia A and up to 6% of all severe haemophilia B patients develop inhibitors.

Patients who have become refractory to replacement factor therapy can be treated with recombinant human factor VIIa. Factor VIIa is an enzyme that can both initiate blood clotting and, at high dose, “bypass” the factor VIII and IX dependent steps involved in effective coagulation. With the current commercially available recombinant product, frequent injections are needed to adequately control or prevent bleeding due to its inherent short half-life.

Using a proprietary genetic fusion technology (patents pending), CSL Behring is in the pre-clinical phase of developing a novel fusion protein formed by linking recombinant Factor VIIa with albumin. Because albumin is the most abundant natural protein in plasma and has a very long half-life (i.e., more than 20 days), the CSL Behring fusion protein is expected to exhibit a good tolerability profile and improved pharmacokinetics that may allow for less frequent dosing.

Preclinical studies have confirmed that CSL Behring's rVIIa-FP has favourable pharmacokinetic properties compared to the existing recombinant product. A half-life extension of greater than 8-fold has been observed. The use of a bypassing agent with an extended half-life could offer significant benefit to those affected by haemophilia A or B with inhibitors and may offer patients the opportunity to be treated less frequently than with the currently available product.

CSL Behring's clinical program intends to demonstrate that an extended half-life rVIIa-FP will result in a requirement for fewer doses while providing adequate therapeutic response in patients with haemophilia A and B with inhibitors.

CSL Behring is a leader in the plasma protein therapeutics industry. Committed to saving lives and improving the quality of life for people with rare and serious diseases, the company manufactures and markets a range of plasma-derived and recombinant therapies worldwide.