EXTON, Pa., Aug. 1, 2012 /PRNewswire/ -- ViroPharma Incorporated (NASDAQ: VPHM) today announced that ViroPharma and Halozyme Therapeutics were notified by the Center for Biologics Evaluation and Research (CBER) division of the U.S. Food and Drug Administration that FDA is evaluating potential safety concerns with Halozyme's recombinant human hyaluronidase enzyme (rHuPH20). Although FDA did not disclose the specific concerns due to their confidentiality requirements, Halozyme informed ViroPharma that FDA is evaluating the potential risk of long term effect of anti-rHuPH20 non-neutralizing antibodies associated with the use of Halozyme's recombinant human hyaluronidase enzyme (rHuPH20) that were detected in a separate development program not involving Cinryze.
In the interim, FDA indicated that studies of the combination of Cinryze® (C1 esterase inhibitor [human]) and rHuPH20 were being placed on temporary clinical hold. ViroPharma's partner Halozyme informed ViroPharma that Halozyme must provide results from additional pre-clinical studies to CBER before clinical investigations in combination with rHuPH20 on temporary hold can resume. FDA stated that the issues are not specific to Cinryze and that ViroPharma could continue to evaluate subcutaneous administration of Cinryze without rHuPH20.
In light of this FDA action, ViroPharma is preparing to commence a Phase 2 study that will evaluate the safety and efficacy of two different doses of the subcutaneous administration of Cinryze as a stand alone therapy. The company received FDA clearance in 2011 of its Investigational New Drug (IND) application and the related Phase 2 clinical protocol to study subcutaneous administration of Cinryze without rHuPH20.
Further, ViroPharma is in the process of notifying European regulatory authorities of CBER's action and will defer enrollment at European sites in the Phase 2 study combining Cinryze and rHuPH20 until there is clarity from FDA on its potential safety concerns."We remain committed to creating therapeutic options for patients suffering from HAE, and will continue to leverage our flexibility to move our Phase 2 subcutaneous program forward," stated Vincent Milano, ViroPharma's president and chief executive officer. Cinryze is approved in the United States as intravenous (IV) administration for routine prophylaxis against angioedema attacks in adolescent and adult patients with hereditary angioedema (HAE), and in Europe for routine prevention, pre-procedure prevention and acute treatment of angioedema attacks in adolescent and adult patients with HAE. 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.