Study Shows C1-Esterase Inhibitor Concentrate Rapidly Relieves Acute, Successive Attacks of Hereditary Angioedema at All Body Sites

NEW ORLEANS, March 1 /PRNewswire/ -- C1-esterase inhibitor (C1-INH) concentrate is an effective, well-tolerated therapy that rapidly relieves acute swelling attacks and successive attacks at any body location in patients with hereditary angioedema (HAE), a rare and serious genetic disorder, according to data presented today at the 2010 American Academy of Allergy, Asthma & Immunology (AAAAI) Annual Meeting. Additional pharmacokinetic data presented at the meeting confirms that C1-INH concentrate has a longer half-life than other treatment options for HAE, which protects patients from rebound attacks.

The latest results from the ongoing, prospective, open label International Multi-center Prospective Angioedema C1-Inhibitor Trial (I.M.P.A.C.T. 2) with C1-INH concentrate showed a median time to the onset of symptom relief of 15 minutes for laryngeal attacks, 20 minutes for abdominal attacks, 28 minutes for facial attacks and 31 minutes for peripheral attacks, such as attacks in the hands and feet. In total, 57 patients who experienced 975 HAE attacks in any body location were studied.

"This study adds to the growing body of clinical evidence that C1-INH replacement therapy should be considered the gold standard for treating acute swelling attacks in hereditary angioedema," said Timothy J. Craig, D.O., Professor of Medicine and Pediatrics at Penn State University in Hershey, PA.  "The new I.M.P.A.C.T. 2 results, which reflect the outcomes of 975 HAE attacks, show that C1-INH concentrate is highly effective, safe and well-tolerated in rapidly relieving symptoms of HAE at many different regions of the body."

HAE is a genetic disorder caused by a deficiency of C1-INH and is inherited in an autosomal dominant manner. Symptoms of HAE include episodes of edema or swelling in the face and the abdomen. Patients who have abdominal attacks of HAE can experience episodes of severe pain, diarrhea, nausea, and vomiting caused by swelling of the intestinal wall. HAE attacks that involve the face can cause painful distortion and painful swelling.  Diagnosis of HAE requires a blood test to confirm low or abnormal levels of C1-INH.  There are estimates of 6,000 to 10,000 or more people with HAE in the U.S.

Long Half-Life Confirmed

Researchers confirmed the long half-life of C1-INH concentrate seen in previous studies by a population pharmacokinetics analysis of I.M.P.A.C.T. 1 based on plasma samples from 97 patients with HAE treated with 10 or 20 U/kg C1-INH concentrate as part of the I.M.P.A.C.T. studies. Sampling was performed at initiation of treatment, one hour and four hours after dosing and with some patients extended up to 24 hours until their discharge from the clinic.

"The long half-life of C1-INH concentrate effectively protects patients with HAE from rebound attacks, an attack that occurs before the complete resolution of a first attack," said Dr. Craig. "In contrast to other treatment options with shorter half-lives, C1-INH provides an extended period of efficacy that has a certain prophylactic effect for patients with HAE."  

About I.M.P.A.C.T. 1

I.M.P.A.C.T. was a study of 124 HAE patients with acute, moderate, or severe abdominal or facial attacks. C1-INH concentrate was administered at two different doses and compared with placebo. The main study endpoints were time to onset of symptom relief from HAE attacks, proportion of subjects with worsening clinical HAE symptoms, and safety.  

The I.M.P.A.C.T. study found that C1-inhibitor concentrate (C1-INH) is effective and safe in rapidly treating acute abdominal and facial skin swellings in adults and adolescents with HAE.  The study found that the median time to symptom relief was 30 minutes after receiving C1-INH compared with 1.5 hours with a placebo.

About I.M.P.A.C.T. 2

Findings of I.M.P.A.C.T. 2 were based on treatment with 20 U/kg bodyweight of C1-INH in 975 episodes of HAE attacks at any body location in 57 patients. The main study end-points were time to onset of symptom relief, complete resolution of all symptoms, and safety.

The median times to complete resolution of all symptoms were reported as early as 8 hours for laryngeal attacks, followed by 10 hours for abdominal attacks, 24 hours for peripheral attacks and 31 hours for facial attacks.  No drug-related serious adverse events have been reported to date, nor were any rebound effects observed following C1-INH administration.

About CSL Behring

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 manufacturers and markets a range of plasma-derived and recombinant therapies worldwide. CSL Behring therapies are indicated for the treatment of coagulation disorders including hemophilia and von Willebrand disease, primary immune deficiencies and inherited respiratory disease. The company's products are also used in cardiac surgery, organ transplantation, burn treatment and to prevent hemolytic diseases in newborns. CSL Behring operates one of the world's largest plasma collection networks, CSL Plasma. CSL Behring is a subsidiary of CSL Limited (ASX: CSL), a biopharmaceutical company headquartered in Melbourne, Australia. For more information, visit www.cslbehring.com.

SOURCE CSL Behring