C1-Esterase Inhibitor Concentrate Rapidly Relieves Abdominal And Facial Attacks In Patients With Hereditary Angioedema, According To Pivotal Study

Main Category: Dermatology
Also Included In: Immune System / Vaccines;  GastroIntestinal / Gastroenterology;  Clinical Trials / Drug Trials
Article Date: 19 Mar 2008 - 0:00 PDT

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C1-esterase inhibitor (C1-INH) concentrate is a safe and effective therapy that rapidly relieves acute abdominal and facial swelling attacks in patients with hereditary angioedema (HAE), a rare and serious genetic disorder, according to data presented at the American Academy of Allergy, Asthma & Immunology (AAAAI) 64th Annual Meeting. Results from the prospective, double-blind International Multi-center Prospective Angioedema C1-Inhibitor Trial (I.M.P.A.C.T. 1), the largest HAE study ever conducted, showed patients receiving C1-INH concentrate had a median time to symptom relief of 30 minutes, versus 90 minutes for patients receiving placebo. Additionally, interim results from I.M.P.A.C.T. 2, also presented at AAAAI, demonstrated for the first time C1-INH replacement therapy's effectiveness in rapidly relieving HAE attacks in peripheral body locations, such as the hands and feet.

HAE is a genetic disorder caused by a deficiency of C1-INH, which is inherited in an autosomal dominant manner. Symptoms include episodes of edema or swelling in the hands and feet, the face, the abdomen, and/or the larynx. Patients who have abdominal attacks can experience episodes of severe pain, diarrhea, nausea, and vomiting caused by swelling of the intestinal wall. Attacks that involve the face and larynx can result in airway closure, asphyxiation, and, if untreated, death. Diagnosis of HAE requires a blood test to confirm low or abnormal levels of C1-INH. It is estimated that 6,000 to 10,000 Americans -- and perhaps more -- suffer from HAE.

"The findings of I.M.P.A.C.T. 1 confirm that C1-INH concentrate can bring rapid relief compared to placebo in HAE patients who experience facial and abdominal attacks," said Jonathan A. Bernstein, MD, FAAAAI, FACP, CCI, Bernstein Clinical Research Center, Cincinnati, OH, and a lead investigator of I.M.P.A.C.T 1. "While HAE attacks can occur all over the body, facial and abdominal swelling can be the most painful and life-threatening for patients and require treatment with a fast-acting therapy."

Currently, there are no specifically-approved therapies for HAE in North America. CSL Behring manufactures and sells C1-INH concentrate in Germany, Austria, Switzerland, and several other countries.

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

Findings were based on a double-blind, placebo-controlled 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 to placebo. The main study endpoints were: time to onset of symptom relief from HAE attacks, and proportion of subjects with worsening clinical HAE symptoms, and safety.

Key Findings

Subjects administered C1-INH 20 U/kg exhibited a highly significant reduction in the median time to onset of HAE symptom relief (30 minutes) compared to subjects receiving placebo (1.5 hours), (p=0.0025). Additionally, the proportion of subjects with worsening HAE symptoms after receiving treatment was significantly lower in the C1-INH P 20 U/kg treated group (p= 0.001). No drug-related serious adverse events were reported.

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

In a separate open label study presented at the AAAAI 64th Annual Meeting, Timothy J. Craig, D.O., Professor of Medicine and Pediatrics at Penn State University in Hershey, PA and his colleagues found C1-INH to be a safe and effective treatment for HAE attacks at any body site.

"This study demonstrates that C1-INH replacement therapy is highly effective at rapidly relieving symptoms of peripheral attacks, along with facial, abdominal, and laryngeal attacks," said Dr. Craig. "These findings demonstrate the versatility of C1-INH and confirm the long-standing observation that C1-INH replacement effectively treats HAE attacks at many different areas of the body."

Study Design and Key Findings

Findings of I.M.P.A.C.T. 2 were based on treatment with 20 U/kg bodyweight of C1-INH in 355 episodes of HAE attacks at any body location in 39 patients. The main study end-points were: time to onset of symptom relief; complete resolution of all symptoms, and safety.

The median time to the onset of relief was less than 33 minutes for abdominal, facial, laryngeal, and peripheral attacks. The median times to complete resolution of symptoms were less than 2.5 hours for laryngeal attacks, 8 hours for abdominal and 24 hours for facial and peripheral attacks.

No drug-related serious adverse events have been reported to date.

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, hemophilia, 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, ZLB Plasma. CSL Behring is a subsidiary of CSL Limited, a biopharmaceutical company with headquarters in Melbourne, Australia. For more information, visit http://www.cslbehring.com.

CSL Behring
http://www.cslbehring.com