DX-2930 is a Potent, Highly Specific, and Potentially Long-Acting Antibody Inhibitor of Plasma Kallikrein

BURLINGTON, MA, USA I February 25, 2013 I Dyax Corp. (NASDAQ:DYAX) today announced results from a preclinical study of DX-2930, their internally developed, fully human monoclonal antibody inhibitor of plasma kallikrein, at the 2013 American Academy of Allergy, Asthma and Immunology (AAAAI) Annual Meeting which is taking place February 22-26, 2013 in San Antonio, TX.

The poster, titled "Discovery and characterization of a fully human monoclonal antibody inhibitor of plasma kallikrein for the treatment of plasma kallikrein-mediated edema," (poster #116) highlighted results of preclinical work that was designed to evaluate the activity of DX-2930 as a long-acting inhibitor of plasma kallikrein (pKal). Dyax currently markets KALBITOR® (ecallantide), a specific pKal inhibitor, for treatment of acute hereditary angioedema (HAE) attacks in patients 16 years of age and older. The Company is exploring DX-2930 as a subcutaneous, long-acting, prophylactic treatment for HAE.

Data demonstrate that DX-2930 is a potent antibody inhibitor of pKal (Ki=0.14 nM) that does not bind prekallikrein or any other serine protease tested. In a preclinical model, DX-2930 reduced carrageenan-induced edema. Pharmacokinetic properties following subcutaneous injection indicate that the antibody is bioavailable (66%) and has a half-life of 12.5 days in non-human primates.

"These data are significant because they indicate that DX-2930 is a potent, highly specific, potentially long-acting antibody inhibitor of plasma kallikrein," said Burt Adelman M.D., Chief Medical Officer and Executive Vice President at Dyax. "DX-2930 may be a viable prophylactic treatment option for hereditary angioedema and other plasma kallikrein-mediated (PKM) diseases. Our focus is on plasma kallikrein inhibition because we think it is the most logical strategy to both treat and prevent HAE attacks."

Gustav Christensen, President and CEO of Dyax added: "The findings presented today represent an important step for Dyax as we move toward our goal of expanding our angioedema portfolio to offer a preventative treatment option for those suffering from HAE and other PKM diseases."

Based upon the attributes of selectivity, specificity and long half-life Dyax has chosen to develop DX-2930 as a self-administered, subcutaneous injection for chronic prevention of HAE attacks. The Company plans to file an Investigational New Drug (IND) application with the United States Food and Drug Administration (FDA) by the end of the second quarter of 2013 and expects to initiate Phase 1 clinical studies in the second half of 2013.

About HAE

Hereditary angioedema (HAE) is a rare acute inflammatory condition characterized by episodes of severe, often painful swelling affecting the extremities, gastrointestinal tract, genitalia, and larynx. HAE is caused by low or dysfunctional levels of C1 esterase inhibitor (C1-INH), a naturally occurring molecule that inhibits plasma kallikrein, a key mediator of inflammation, and other serine proteases in the blood. HAE is estimated to affect up to 1 in 50,000 individuals. Learn more at www.HAEHope.com.

About Dyax

Dyax is a fully integrated biopharmaceutical company focused on the discovery, development and commercialization of novel biotherapeutics for unmet medical needs. The Company’s key value drivers are the KALBITOR® (ecallantide) business and the angioedema portfolio, as well as the Licensing and Funded Research Program (LFRP).

Dyax developed KALBITOR on its own and, since February 2010, the Company has been selling it in the United States for the treatment of acute attacks of hereditary angioedema (HAE) in patients 16 years of age and older. Outside the United States, the Company has established partnerships to obtain regulatory approval for and commercialization of KALBITOR in certain markets and is evaluating opportunities in others.

The Company is currently developing products to expand its angioedema portfolio, including a suite of diagnostic assays to identify plasma kallikrein mediated (PKM) angioedema and a therapeutic candidate, DX-2930, for the prophylactic treatment of HAE and other PKM angioedemas.

KALBITOR and DX-2930 were identified using Dyax’s patented phage display technology, which rapidly selects compounds that bind with high affinity and specificity to therapeutic targets. Dyax leverages this technology broadly through the LFRP. This program has provided the Company a portfolio of product candidates being developed by its licensees, which currently includes 13 royalty and/or milestone bearing product candidates in various stages of clinical development, including three in Phase 3 trials.

Dyax is headquartered in Burlington, Massachusetts. For additional information about Dyax, please visit www.dyax.com.

SOURCE: Dyax