ViroPharma's Cinryze® (C1 esterase inhibitor [human]) Open Label Prophylaxis Study Showed Up To 2.6 Years Of Effectiveness In Majority Of Subjects With Hereditary Angioedema

EXTON, Pa., July 27, 2012 /PRNewswire/ -- ViroPharma Incorporated (Nasdaq: VPHM) today announced the publication of data demonstrating that routine prophylactic use of Cinryze® (C1 esterase inhibitor [human]) provided effectiveness and maintained a generally favorable safety profile in the majority of treated subjects with hereditary angioedema (HAE). HAE is a rare, severely debilitating, life-threatening genetic disorder caused by a deficiency of a human plasma protein called C1 inhibitor. The paper entitled Safety and Efficacy of Prophylactic Nanofiltered C1-inhibitor in Hereditary Angioedema by Drs. Bruce L. Zuraw and Ira N. Kalfus describes the maintenance of effectiveness and the safety profile of Cinryze as continuing prophylactic therapy in a large cohort of subjects with HAE. These data have been published in the July 14th online edition of The American Journal of Medicine (AJM).  The company expects the data to appear in the September print issue.

According to the publication, subjects were to be treated with Cinryze 1000 units every 3 to 7 days based on the decision of the investigator; subjects in the study experienced a 93.7 percent reduction in attacks while taking prophylactic Cinryze (median of 0.19 attacks per month) compared with the median historical rate at baseline (3 attacks per month). Some 87.7 percent reported an attack frequency of one or less attack per month during prophylactic Cinryze and 34.9 percent had no attacks during the study. Some 7.5 percent of subjects experienced relatively frequent attacks despite twice-weekly Cinryze. Additionally, though 18 subjects (12.3 percent) had an overall attack rate of more than 1 per month on Cinryze, only 4 subjects (2.7 percent) failed to achieve an attack rate of one or less per month when treated with Cinryze at the recommended twice per week schedule.

Overall, subjects on average received 1.4 injections per week throughout the study period. The efficacy of Cinryze directly correlated with the interval between injections where 1000 units every 2 to 4 days resulted in 1 attack for every 132 days of treatment compared to 1000 units every 6 to 7 days which resulted in 1 attack for every 46 days of treatment. No clinical characteristics predicted the response to prophylactic C1INH-nf, including historical attack frequency.

At enrollment, 42 subjects (28.8 percent) were taking regular prophylactic androgens in an effort to prevent attacks of HAE. During the study, 23 subjects (54.8 percent) discontinued androgens, 6 subjects (14.3 percent) discontinued regular use and switched to as-needed use, 5 subjects (11.9 percent) reduced the androgen dose, and 8 subjects (19 percent) remained on the same dose. The median monthly attack rate in the 23 subjects who discontinued androgens went from 3 attacks per month while on androgens to 0 attacks per month when switched to prophylactic Cinryze.

No subjects discontinued the study drug because of an adverse event. Eighty-six percent of treatment-emergent adverse events were of mild or moderate intensity.  A total of 99 of 101 serious adverse events reported were considered not related to Cinryze, and 2 serious adverse events (musculoskeletal chest pain and major depression) were of unknown relationship.

"The results of this study reinforce the efficacy and safety profile of Cinryze when used up to 2.6 years and the clinically relevant impact Cinryze can offer to people living with HAE who are experiencing recurrent attacks," commented Dr. Bruce L. Zuraw, professor of medicine and program director of the Allergy and Immunology Fellowship Program at the University of California at San Diego. "These data suggest that prophylactic Cinryze should be considered by the physician for any patient with hereditary angioedema who requires or desires prophylactic treatment."

Study Design

An open-label, multicenter extension study was performed to evaluate the safety and efficacy of Cinryze involving 146 subjects with HAE who were treated for up to 2.6 years in centers throughout the United States. Subjects were to be treated with Cinryze 1000 units every 3 to 7 days based on the decision of the investigator. The primary efficacy variable was the number of attacks of angioedema experienced.

About Cinryze^® (C1 esterase inhibitor [human])

Cinryze is a highly purified, pasteurized and nanofiltered plasma-derived C1 esterase inhibitor product.  In the U.S., Cinryze is approved by the FDA for routine prophylaxis against angioedema attacks in adolescent and adult patients with HAE.  In the E.U., the product is approved by the EMA for the treatment and pre-procedure prevention of angioedema attacks in adults and adolescents with hereditary angioedema (HAE), and routine prevention of angioedema attacks in adults and adolescents with severe and recurrent attacks of hereditary angioedema (HAE), who are intolerant to or insufficiently protected by oral prevention treatments or patients who are inadequately managed with repeated acute treatment. Cinryze is for intravenous use only.

Severe hypersensitivity reactions to Cinryze may occur.  Thrombotic events have occurred in patients receiving Cinryze, and in patients receiving off-label high dose C1 inhibitor therapy.  Monitor patients with known risk factors for thrombotic events.  With any blood or plasma derived product, there may be a risk of transmission of infectious agents, e.g. viruses and, theoretically, the CJD agent. The risk has been reduced by screening donors for prior exposure to certain virus infections and by manufacturing steps to reduce the risk of viral transmission including pasteurization and nanofiltration. 

The most common adverse reactions in clinical trials associated with Cinryze were rash, headache, nausea, erythema, phlebitis and local reactions at the injection site.  Adverse events of sinusitis and upper respiratory infection also were observed in clinical trials.  No drug-related serious adverse events (SAEs) were reported in clinical trials.

Please visit http://www.viropharma.com/products/cinryze.aspx for the full U.S. Prescribing Information; the prescribing information for other countries can be found at www.viropharma.com. 

About Hereditary Angioedema (HAE)

HAE is a rare, severely debilitating, life-threatening genetic disorder caused by a deficiency of C1 inhibitor, a human plasma protein. This condition is the result of a defect in the gene controlling the synthesis of C1 inhibitor. C1 inhibitor maintains the natural regulation of the contact, complement, and fibrinolytic systems, that when left unregulated, can initiate or perpetuate an attack by consuming the already low levels of endogenous C1 inhibitor in HAE patients. Patients with C1 inhibitor deficiency experience recurrent, unpredictable, debilitating, and potentially life threatening attacks of inflammation affecting the larynx, abdomen, face, extremities and urogenital tract. Patients with HAE experience approximately 20 to 100 days of incapacitation per year. There are estimated to be at least 6,500 people with HAE in the United States and at least 10,000 people in the European Union.

For more information on HAE, visit the U.S. HAE Association's website at www.haea.org and the HAEi's (International Patient Organization for C1 Inhibitor Deficiencies) website at www.haei.org.

About ViroPharma Incorporated

ViroPharma Incorporated is an international biopharmaceutical company committed to developing and commercializing novel solutions for physician specialists to address unmet medical needs of patients living with diseases that have few if any clinical therapeutic options.  ViroPharma is developing a portfolio of therapeutics for rare and Orphan diseases including C1 esterase inhibitor deficiency, Friedreich's Ataxia, and adrenal insufficiency, cytomegalovirus (CMV); and recurrent C. difficile infection (CDI).  Our goal is to provide rewarding careers to employees, to create new standards of care in the way serious diseases are treated, and to build international partnerships with the patients, advocates, and health care professionals we serve.  ViroPharma's commercial products address diseases including hereditary angioedema (HAE), seizures, adrenal insufficiency and C. difficile-associated diarrhea (CDAD); for full U.S. prescribing information on our products, please download the package inserts at http://www.viropharma.com/Products.aspx; the prescribing information for other countries can be found at www.viropharma.com. 

ViroPharma routinely posts information, including press releases, which may be important to investors in the investor relations and media sections of our company's web site, www.viropharma.com. The company encourages investors to consult these sections for more information on ViroPharma and our business.

Forward-Looking Statements

Certain statements in this press release contain forward-looking statements that involve a number of risks and uncertainties. Forward-looking statements provide our current expectations or forecasts of future events. Forward-looking statements in this press release include statements regarding the therapeutic use, safety, efficacy, tolerability and potential of Cinryze in an open label prophylactic study.  Our actual results could differ materially from those results expressed in, or implied by, these forward-looking statements. The commercialization of pharmaceutical products is subject to risks and uncertainties. The data that were discussed in The American Journal of Medicine article are subject to different interpretations and may not be predictive of the results of any individual's results or of how Cinryze performs in commercial usage.  These factors, and other factors, including, but not limited to those described in our annual report on Form 10-K for the year ended December 31, 2012 and 10-Q for the quarter ended March 31, 2012 filed with the Securities and Exchange Commission, could cause future results to differ materially from the expectations expressed in this press release. The forward-looking statements contained in this press release are made as of the date hereof and may become outdated over time. ViroPharma does not assume any responsibility for updating any forward-looking statements. These forward looking statements should not be relied upon as representing our assessments as of any date subsequent to the date of this press release.

SOURCE ViroPharma Incorporated