Dyax Corp. Enters into New Loan Agreement with HealthCare Royalty Partners

$80 Million Commitment Provides $20 Million in Cash and Refinancing of Existing Loan at Reduced Interest Rate

Cambridge, MA, January 4, 2012 – Dyax Corp. (NASDAQ: DYAX) announced today that it has entered into a loan agreement with an affiliate of HealthCare Royalty Partners (“HC Royalty”) through which it has received an initial loan of $20 million and a commitment to refinance its existing debt with HC Royalty at a reduced interest rate in August 2012.

The initial loan of $20 million is unsecured and bears interest at an annual rate of 13% through August 2012 at which time it will be combined with a second loan tranche. The second tranche will be used to refinance the Company’s outstanding debt of approximately $56.7 million and will be made at 102% of the original principal amount. Together, the collective loan will be secured only by the Company’s phage display Licensing and Funded Research Program (“LFRP”) and will bear an interest rate of 12%. It will mature in August 2018 and can be repaid without penalty beginning in August 2015. Should the second tranche not be funded, the initial tranche will continue to bear interest at a rate of 13% and will mature on June 30, 2013.

“This loan agreement provides additional balance sheet strength while reducing the cost of capital of our debt facility,” stated Gustav Christensen, President and Chief Executive Officer of Dyax Corp. “The LFRP franchise, on which our royalty portfolio is built, remains a key value driver for Dyax with opportunities for growth fueled by more than 75 biopharmaceutical company licensees and 18 clinical stage programs. These new funds provide us with the ability to build out Dyax’s angioedema platform as well as grow the KALBITOR business.”

“Dyax’s LFRP franchise is an asset of significant value that has performed above our expectations over the past few years. We are pleased to strengthen our partnership with the Company,” commented Gregory B. Brown, M.D., Co-Founder and Managing Director of HC Royalty.

Dyax will continue to receive a share of the LFRP revenues under the new loan agreement, including participation in revenues derived from products commercialized by Dyax licensees. The new loan agreement does not apply to KALBITOR, Dyax’s internal drug development programs or to any of its co-development programs. Upon repayment of all HC Royalty loan amounts, all rights to the LFRP revenues will revert to Dyax.

Please refer to the Current Report on Form 8-K that will be filed by Dyax with the Securities and Exchange Commission on or about the date hereof for additional details on the terms of the new loan agreement.

About Dyax’s Phage Display Licensing and Funded Research Program (LFRP)
Dyax provides access to its phage display libraries and know-how through various types of collaborations through its LFRP. In this way, Dyax offers its partners therapeutic discovery capabilities that also extends into areas such as imaging, diagnostics, research reagents and affinity purification. Dyax has more than 75 revenue generating LFRP agreements, including those with a number of the top biopharmaceutical companies. The success of the Company’s LFRP royalty portfolio is illustrated by the program’s advanced licensee pipeline that includes 18 candidates in clinical development of which four are in Phase 3 clinical trials, four are in Phase 2 and ten are in Phase 1.

About Dyax
Dyax is a fully integrated biopharmaceutical company focused on discovering, developing and commercializing novel biotherapeutics for unmet medical needs. The Company’s lead product, ecallantide, has been approved under the brand name KALBITOR® in the United States for the treatment of acute attacks of hereditary angioedema (HAE) in patients 16 years of age and older.

Dyax is commercializing KALBITOR in the United States independently, and establishing strategic partnerships to develop and commercialize ecallantide for the treatment of HAE in key regions worldwide. Currently, Dyax has partnership agreements for regions including Europe, Japan, Russia, the Middle East, Israel, North Africa, Australia, New Zealand, Latin America (excluding Mexico), and the Caribbean. The Company is also exploring other potential indications for ecallantide, either alone or through partnerships, including drug-induced angioedema.

For more information, visit   www.dyax.com.

About HealthCare Royalty Partners
HealthCare Royalty Partners is a global healthcare investment firm with more than $1.5 billion under management. The Firm invests principally in commercial-stage healthcare companies and products through drug royalty acquisitions and structured financings. HC Royalty’s investment team has over 100 years of healthcare related experience including principal investing, structured finance, healthcare industry senior management, Wall Street research and consulting, and scientific and clinical experience. For more information, visit www.healthcareroyalty.com.

Dyax Disclaimer
This press release contains forward-looking statements, including statements regarding the anticipated funding of the Subequent Loan in August 2012; Dyax’s LFRP; the LFRP’s potential to generate future revenues and the potential for Dyax’s licensees to bring products to market. Statements that are not historical facts are based on Dyax’s current expectations, beliefs, assumptions, estimates, forecasts and projections about the industry and markets in which Dyax competes. The statements contained in this release are not guarantees of future performance and involve certain risks, uncertainties and assumptions, which are difficult to predict. Therefore, actual outcomes and results may differ materially from what is expressed in such forward-looking statements. The closing of the Subsequent Loan is subject to customary closing conditions and any failure of Dyax to satisfy these conditions or other events, such as any changes in law that would affect Dyax’s ability to secure the loans with the LFRP, could result in the Subsequent Loan not being funded. Important factors that may affect the extent of Dyax’s patent portfolio and its potential for the identification of novel compounds include the risks that: Dyax may not be able to obtain and maintain intellectual property protection for its phage display technology; others may develop technologies superior to Dyax’s phage display technology; and other risks that are described or referred to in Dyax’s most recent Annual Report on Form 10-K and other periodic reports filed with the Securities and Exchange Commission. Dyax cautions investors not to place undue reliance on the forward-looking statements contained in this release. These statements speak only as of the date of this release, and Dyax undertakes no obligations to update or revise these statements, except as may be required by law.

Dyax, the Dyax logo and KALBITOR are the registered trademarks of Dyax Corp.

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