Halozyme's Enhanze™ technology, a proprietary drug delivery platform using recombinant human hyaluronidase enzyme (rHuPH20) facilitates the absorption and dispersion of drugs or fluids that are injected under the skin. Recombinant HuPH20 transiently generates channels in subcutaneous tissues to increase the absorption and spread of injected drugs.About the StudyThis open-label, multiple-dose Phase 2 study was conducted in 12 subjects with HAE who previously participated in the ViroPharma trial evaluating the pharmacokinetics of subcutaneous injections of Cinryze when given alone relative to intravenous infusion. Qualified subjects participated in a single 18-day study period, followed by a 30-day post-treatment follow-up. A 1000U or 2000U dose of Cinryze in combination with rHuPH20 was administered as a single subcutaneous injection, twice weekly, allowing within-subject comparison across the different methods of administration. Plasma C1 INH functional activity was assessed by chromogenic assay and plasma C1 inhibitor antigenic concentration and C4 complement levels were assessed by ELISA. Additional information about this subcutaneous Cinryze clinical trial can be found at clinicaltrials.gov. 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.