CAMBRIDGE, Mass.–(Business Wire)–
Dyax Corp. (NASDAQ: DYAX) announced the publication of a first-ever
comprehensive examination of the economic burden associated with the treatment
of acute attacks and chronic management of hereditary angioedema (HAE). The
results, published today in the Annals of Allergy, Asthma, and Immunology, bring
to light the substantial direct and indirect medical costs of the disease on
patients, payers and society. The economic study is one component of a larger
survey-based Burden of Illness (BOI) study which assessed both the economic and
humanistic burden of HAE. The BOI study was conducted by Dyax in conjunction
with the United States Hereditary Angioedema Association (HAEA) and United
Biosource Corporation (UBC).

Monetizable and non-monetizable costs were captured in the study and highlighted
HAE`s costly and detrimental impact for patients, payers and society.
Monetizable costs averaged $42,000 annually per HAE patient. Costs included
direct costs associated with emergency care, physician visits, hospital stays,
tests and procedures, and medications, as well as indirect costs such as missed
work days and reduced productivity. Costs increased with disease severity.
Patients who reported their most recent attack as severe amassed an estimated
$96,000 in annual per patient costs. The largest cost component, accounting for
approximately 48% of total costs for the average HAE patient, is emergency room
visits and hospital stays for managing acute attacks.

Additional non-monetizable costs were reflected in the study yet were not part
of the quantifiable analysis. These costs, which further exacerbate the economic
burden on patients, payers and society, included the burden of increased
depression, reduced income potential and missed opportunities. These
non-monetizable costs consist of the cost of managing depression (42.5% percent
of patients showed signs of at least mild depression and 19.5% reported that
they were taking psychotropic or antidepressant medication), and the financial
consequence of common activities being impacted such as driving, exercising and
studying. Other costs that were not part of the analyses include the expense of
improper procedures and medications as well as indirect costs related to
non-paid caregivers. As such, these compounding costs underestimate the total
costs associated with HAE.

“I have made several sacrifices in my career and personal life because of HAE.
The unpredictability and frequency of my laryngeal attacks have made it
impossible for me to continue working as a computer operator and, as a result,
I`ve been out of work for twelve years,” said Joan Angert, who was not
officially diagnosed with HAE until nine years ago, though she suffered from its
symptoms for 30 years.

HAE is a rare genetic disease characterized by unpredictable acute episodes of
severe, often painful swelling affecting the extremities, abdomen and the
larynx. On average, participants experienced 26.9 acute attacks per year. HAE is
estimated to affect 1:10,000 to 1:50,000 individuals. More than half (56.5%) of
the respondents from the study reported that they experienced painful abdominal
symptoms for their most recent attacks while 24.5% reported laryngeal symptoms.
Laryngeal attacks pose the greatest risk with the potential for asphyxiation.

“Our study provides a comprehensive survey of the burden patients with HAE live
with,” explained lead author David Wilson, MA, Assistant Professor, MGH
Institute of Health Professions. “The breadth of the economic consequences
highlighted in this study hopefully will raise people`s understanding of the
disease and inform them of the value of having new therapies available for the
people with HAE.”

Study Methodology

The Burden of Illness study, developed in consultation with expert health
economists, HAE experts, and HAE patients, was conducted from November 2007 to
January 2008. Study participants were recruited using the HAEA database of HAE
patients. The study collected responses from 457 HAE patients via an
Institutional Review Board-approved, web-based survey that solicited information
on attack characterization, acute attack treatment, chronic disease management,
impact on work and patient costs. A standardized instrument, the Work
Productivity and Activity Impairment (WPAI) tool, was included to assess impact
on work and productivity. Standard medical costs and U.S. average wage costs
were assigned to survey items to assess direct medical and indirect costs,
respectively.

About HAE

Hereditary angioedema (HAE) is a rare acute inflammatory condition characterized
by episodes of severe, often painful swelling affecting the extremities, the
gastrointestinal tract, the genitalia, and in the 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 1:10,000 to
1:50,000 individuals. Learn more at www.HAEHope.com.

About Dyax

Dyax is a fully integrated biopharmaceutical company focused on discovering,
developing and commercializing novel biotherapeutics for unmet medical needs,
with an emphasis on inflammatory and oncology indications. The Company utilizes
its proprietary drug discovery technology, phage display, to identify antibody,
small protein and peptide compounds for clinical development. Dyax also
leverages this technology broadly with over 70 revenue generating licenses and
collaborations for therapeutic discovery, as well as in non-core areas such as
affinity separations, diagnostic imaging, and research reagents. Dyax is
headquartered in Cambridge, Massachusetts. For online information about Dyax
Corp., please visit www.dyax.com.

Dyax Corp.
Ivana Magovčević-Liebisch, 617-250-5759
Executive Vice President Corporate Development and General Counsel
imagovcevic@dyax.com
or
Nicole Jones, 617-250-5744
Director, Investor Relations and Corporate Communications
njones@dyax.com

Copyright Business Wire 2010