CAMBRIDGE, Mass. --Sept. 16, 2002--Dyax Corp. (Nasdaq: DYAX) today announced the launch of an automated call center to facilitate U.S.-based patient enrollment in a second phase II clinical trial of the Company's investigational compound DX-88, for the treatment of patients with hereditary angioedema (HAE). This DX-88 study will be conducted in collaboration with Genzyme Corp., and will complement an active phase II study of DX-88 in Europe. Dyax is in the process of establishing study centers for the new trial in both the United States and Europe, and expects to study up to 48 HAE patients, with enrollment beginning in September.

"Unlike in Europe and other parts of the world, hereditary angioedema patients in the United States do not have access to an approved therapy for debilitating and potentially fatal HAE attacks. We are excited that Dyax is attempting to fill this void by testing DX-88 as an acute attack therapy. The automated call center is an innovative and technologically advanced approach that will efficiently match qualified patients with the closest clinical trial center. We are also delighted that call center data will be analyzed to identify geographic patient clusters for potential additional clinical trial sites," commented Anthony Castaldo, Board Member of the Hereditary Angioedema Association, a national patient advocacy group.

The automated call center, developed and hosted by Appriss, Inc. of Louisville, KY, utilizes speech recognition technology to streamline the caller screening process by confidentially collecting caller information (in compliance with all applicable laws relating to patient confidentiality), providing real-time information about open clinical trial sites. Upon caller approval, information can be transferred immediately to Dyax and active research centers in the patient's geographical area, allowing the patient to be considered for entry into the DX-88 study. Although a study site may not be immediately available in the patient's area, he or she will be notified if or when a local center becomes active. By gathering demographic information, the Appriss software can map where patients live, allowing Dyax to identify patient clusters in order to pursue additional clinical site locations.

While incidence numbers are difficult to obtain, primarily due to the rarity of HAE, it is believed that hereditary angioedema affects between 1/10,000 and 1/50,000 people, and that between 10,000 and 86,000 people in the United States are afflicted with the disease. HAE is caused by the deficiency of the C1 esterase inhibitor (C1-INH), a molecule that inhibits kallikrein and other serine proteases. The disease is characterized by acute episodic attacks of edema (swelling) in body parts, most notably the hands, feet, face, and airway passages. In addition, patients often have bouts of severe abdominal pain, nausea, and vomiting caused by swelling in the intestinal wall. Using its patented phage display technology, Dyax has identified its DX-88 compound, a small protein with high affinity and specificity for inhibiting kallikrein, as a potential therapeutic for the treatment of HAE. Due to its high affinity and specificity, DX-88 potentially may have fewer side effects and greater effectiveness than recombinant or plasma derived C1-INH. C1-INH is the current standard-of-care in Europe but is unavailable in the United States.

Patients and parents or guardians of patients with hereditary angioedema in the U.S. can call:

866-814-4915

to register for Dyax's clinical trial investigating the effects of its compound DX-88 on acute attacks of HAE. This toll-free number will remain live for an indefinite period of time, so that Dyax can accumulate caller information in preparation for this and potential future clinical trials involving the use of DX-88 for the treatment of HAE trials.

Physicians and clinical investigators interested in learning more about Dyax's clinical trials can contact the company via email (clinicaltrials@dyax.com) or visit the Company's website (www.dyax.com). Additional information about HAE is available on the HAE Association website: www.hereditaryangioedema.com).

Dyax Corp.

Dyax Corp. is a biopharmaceutical company focused on the discovery, development and commercialization of therapeutic products. The Company uses its patented phage display technology to rapidly identify a broad range of protein, peptide, and antibody compounds that bind with high affinity and high specificity to targets of interest, with the objective of selecting those compounds with the greatest potential for advancement into clinical development. Dyax currently has two recombinant proteins in phase I and II clinical trials. DX-88 is being studied in two indications (hereditary angioedema and cardiopulmonary bypass), while DX-890 is being studied for cystic fibrosis. Dyax leverages its technology broadly through licenses and collaborations in therapeutics and in non-core areas of affinity separations, diagnostics and imaging, and research reagents. Through its subsidiary, Biotage, Inc., Dyax develops, manufactures and sells chromatography separations systems and products worldwide for drug discovery and purification.

Dyax Disclaimer

This press release contains forward-looking statements, including statements regarding the prospects for clinical trials and commercialization of the DX-88 compound. 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. Important factors which may affect the future commercialization of DX-88 include the risks that DX-88 may not show therapeutic effect or an acceptable safety profile in clinical trials or could take a significantly longer time to gain regulatory approval than we expect or may never gain approval; Dyax is dependent on the expertise, effort, priorities and contractual obligations of third parties in the clinical trials, manufacture, marketing, sales and distribution of Dyax's biopharmaceuticals; DX-88 may not gain market acceptance; Dyax's may not be able to obtain and maintain intellectual property protection for its products and technologies; others may develop technologies or products superior to Dyax's technologies or products; and other risk factors 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 and the Dyax logo are the registered trademarks of Dyax Corp.

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Contact:

Dyax Corp.
Tony Williams, M.D., 617/225-2500 x5801
twilliams@dyax.com