Nanofiltered C1 inhibitor concentrate (C1INH-nf, CinryzeR) is an effective and safe treatment for all types of acute hereditary angioedema (HAE) attacks, according to results released here at the 2008 Annual Meeting of the American College of Allergy, Asthma & Immunology (ACAAI).

Bruce Zuraw, MD, with the University of California at San Diego, and colleagues elsewhere, presented data from a study of 82 patients in whom a total of 447 HAE attacks were treated with Cinryze as part of an ongoing open-label extension study.

Patients were originally enrolled in two phase III trials of Cinryze for the acute and long-term prophylactic treatment of HAE.

Those individuals who participated in the extension phase study were eligible to receive open-label injections (1,000 units i.v.) of Cinryze for acute HAE attacks occurring at any location. Patients who did not improve with the first injection could receive a second open-label injection 60 minutes later.

The mean number of attacks per patient was 5.45±8.28. Patients received one injection for 287 attacks and two injections for 160 attacks.

The primary location of the treated attacks was the extremities in 68 patients, facial in 48, gastrointestinal in 272, genitourinary in 9, and laryngeal in 50.

Results showed that Cinryze treatment produced a rapid improvement in symptoms. In fact, the median time to improvement was 30 minutes, and 93.4% of patients reported improvement within four hours. Rapid improvement occurred irrespective of the number of injections, and similar responses were documented in all attack locations.

Importantly, no patient treated for laryngeal attacks required hospitalization or intubation, and there were no serious treatment-related side effects.

Dr. Zuraw, who is a professor of rheumatology, allergy and immunology, said that the findings are in line with clinical experience of C1 inhibitors in Europe and support the use of Cinryze as the treatment standard for acute HAE attacks.

Cinryze was approved in October for routine prophylaxis for HAE and is expected to be available in early December. ViroPharma, the company that is commercializing the drug, plans to provide the U.S. Food and Drug Administration with a supplemental biologics license application for the acute indication this year.

Hereditary angioedema is a genetic disorder characterized by recurrent, unpredictable, debilitating, and potentially life-threatening episodes of edema in the larynx, abdomen, face, extremities, and urogenital tract. The condition (also called C1 inhibitor deficiency) affects approximately 10,000 people in the U.S., where there are currently no approved treatments for acute HAE attacks.

Written by Jill Stein
Jill Stein is a Paris-based freelance medical writer.
jillstein03 (at) gmail.com