Prodromal Symptoms Warn of Hereditary Angioedema Attacks, Give Patients Time to Start Therapy and Decrease Morbidity

November 7, 2009

MIAMI BEACH, Fla., Nov. 7 /PRNewswire/ -- Most patients with hereditary angioedema (HAE) have prodromal symptoms that signal an oncoming HAE attack giving the patients sufficient time to initiate treatment and decrease the morbidity associated with that attack, according to survey findings presented today at the 2009 American College of Allergy, Asthma & Immunology (ACAAI) Annual Meeting. Early recognition of symptoms such as fatigue and nausea, which occur frequently before an acute HAE attack, can provide patients with up to 24 hours to initiate treatment before further onset of the attack.

Administered in parallel with the ongoing, open label International Multi-center Prospective Angioedema C1-Inhibitor Trial (I.M.P.A.C.T. 2), the survey was designed to evaluate prodromal symptoms at the time of treatment of HAE attacks. Thirty-one patients experiencing 253 attacks were treated with C1 esterase inhibitor concentrate (C1-INH). Prodromal symptoms were reported before 171 of these attacks (67.6 percent). The start of symptoms ranged from 20 minutes to 24 hours before the onset of HAE exacerbations, with a median duration of 12 hours. The most commonly reported prodromal symptoms were fatigue (41.9%), nausea (26.1%) and flu-like feelings (22.1%). Other prodromal symptoms included urticaria-like skin eruptions (11.1%), non-itchy rash (11.1%), bowel movement change (9.1%), abdominal rumbling (7.5%), and tingling (4.0%).

"For patients suffering from HAE, timely treatment is critical to effective management of this debilitating and life-threatening disorder," said Timothy J. Craig, D.O., Professor of Medicine and Pediatrics at Penn State University in Hershey, PA., and one of the study's investigators. "Our study shows that patients who recognize the warning signs of an HAE attack have adequate time to initiate treatment and improve their outcomes."

HAE is a genetic disorder affecting approximately 6,000 to 10,000 Americans and is caused by a deficiency of C1-INH, which is inherited in an autosomal dominant manner. 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.

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 640 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 time to the onset of symptom relief was 16 minutes for laryngeal attacks, 23 minutes for abdominal attacks, 28 minutes for facial attacks and 31 minutes for peripheral attacks, such as attacks in the hands and feet. The median times to complete resolution of all symptoms were reported as early as 8 hours for laryngeal attacks, 11 hours for abdominal, 24 hours for facial and 25 hours for peripheral 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 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, CSL Plasma. CSL Behring is a subsidiary of CSL Limited, a biopharmaceutical company with headquarters in Melbourne, Australia. For more information, visit www.cslbehring.com.

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