CSL Behring Shows Positive Results For Treatment Of Hereditary Angioedema
CSL Behring has reached the primary endpoint of a Phase III clinical trial of human pasteurized C1-inhibitor (C1-INH) concentrate to treat patients with hereditary angioedema (HAE), a rare genetic disorder that can lead to painful and sometimes life-threatening attacks of edema (swelling) of the face, airway, abdomen, and extremities.
The results from the Phase III, double blind, placebo-controlled trial I.M.P.A.C.T. (International Multi-centre Prospective Angioedema C1-inhibitor Trial), showed that patients treated with 20 U/kg b.w. C1-INH experienced a highly significant reduction in time to onset of relief of symptoms of HAE attacks compared to placebo (p= 0.003, one sided). In addition, all secondary endpoints of the trial have shown significant positive results, e.g. worsening of symptoms (p= 0.001, one sided).
"The results of this trial can immediately impact the lives of the thousands of HAE patients around the world who live with the burden of acute HAE attacks without approved treatment," said Timothy Craig, M.D., professor of medicine and pediatrics, Penn State Hershey Medical Center, USA, coordinating investigator of the I.M.P.A.C.T. trial.
I.M.P.A.C.T. is a multi-center, prospective clinical trial conducted globally in more than 45 centers in 15 countries, enrolling 125 patients, and is the largest trial ever conducted in HAE. For the first time, a dose comparison study was conducted for a human C1-INH comparing 20U/ kg b.w. and 10U/ kg b.w. in a randomized, placebo-controlled, double-blind study design. The results will be submitted in the near future to the United States Food and Drug Administration, Health Canada and European Health Authorities in support of applications to license C1-INH concentrate for the treatment of acute attacks of HAE in the U.S., Canada, and Europe. CSL Behring has manufactured and provided C1-INH concentrate to HAE patients for over 20 years in Germany, Austria, Switzerland, and several other countries, where it is licensed under the trade name Berinert P for the treatment of acute HAE attacks.
"The successful completion of this trial confirms longstanding observations made from the administration of more than 300,000 treatments of C1-INH concentrate in Europe. We are delighted that it will now be submitted for registration in the UK," said Dr. Hilary Longhurst, Consultant Immunologist, Barts and The London NHS Trust, London, England, and investigator of the I.M.P.A.C.T. trial.
Study design and results
HAE is caused by the partial absence of functional C1 inhibitor in the blood. The objective of I.M.P.A.C.T. was to assess whether replacing the C1 protein missing in patients with HAE through treatment with C1-INH can address the underlying mechanism of the disease.
I.M.P.A.C.T. evaluated in a prospective and double-blind fashion whether different doses of human pasteurized C1-INH concentrate lead to faster relief of acute symptoms of abdominal and facial attacks compared with placebo in patients with HAE. It is also the largest dose comparison study ever done in HAE. To be eligible for inclusion in the study, patients had to be six years of age or older, with a diagnosis of C1-INH deficiency and a documented history of facial or abdominal attacks.
The primary objective was to show that C1-INH shortens the time to onset of relief of symptoms of abdominal or facial HAE attacks. The primary endpoint was time between start of C1-INH administration and onset of relief of symptoms from abdominal or facial attacks as determined by the subject's assessment. The median time to onset of relief of symptoms in the 20 U/kg b.w. C1-INH treatment group was 30 minutes, compared to 1.5 hours for patients who received placebo.
The secondary endpoint, that is, the proportion of subjects with increased intensity of clinical HAE symptoms between two and four hours after start of study drug administration compared to baseline, showed also significant improvement (p= 0.001, one sided), as did time to the complete resolution of HAE symptoms (p= 0.024, one sided). Dose comparison revealed that the 20 Units C1-INH/kg was significant versus placebo. The 10 Units C1-INH/kg was superior to placebo, but was not significant.
"C1-INH really made a difference in improving the quality of my life and that of many other HAE patients," said Henrik Boysen, chairman of the Patient Association for HAE in Denmark.
"We are excited that the track is set to make this product available in many countries where currently no licensed product is available."