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Reliability and Validity of Dyax's Novel Patient Reported Outcome Measures (PROs) Affirmed in Published Study

CAMBRIDGE, Mass.--(BUSINESS WIRE)--Sep 10, 2009 - Dyax Corp. (NASDAQ:DYAX) today announced a study published evaluating the Company's novel Patient Reported Outcome Measures (PROs) used to assess hereditary angioedema (HAE) attacks affirmed the PROs as valuable instruments in capturing HAE symptom severity and impact of treatment. The study, “Psychometric Validation of Two Patient-Reported Outcome Measures to Assess Symptom Severity and Changes in Symptoms in Hereditary Angioedema,” examined the PROs used in Dyax's HAE clinical development program and was published in the September issue of the journal Quality of Life Research.

The overall analysis supported the robust measurement properties, including reliability and validity, of the two disease-specific PROs created by Dyax as efficacy measurements in the Company's Phase 3 HAE clinical program. In addition, the study researcher and lead author Margaret Vernon, PhD, Research Scientist of the United BioSource Corporation, Center for Health Outcomes Research concluded that the two PRO instruments comprehensively evaluate all the possible signs and symptoms experienced by patients during an HAE attack.

“HAE is a complex disease that can manifest in multiple swelling patterns of differing severities and symptoms in a single acute episode,” Dr. Vernon noted, “There is a critical need for measures that can take into account all the relevant symptoms of an attack, including capturing the signs and symptoms that are known only to the patient (such as internal swelling, stomach cramping and pain).” Previous instruments, used in other HAE studies to evaluate such attacks, are limited as they assess only a single symptom and cannot accurately depict the complexity and variability of an attack.

The objective of the study was to evaluate the psychometric properties, including the reliability, validity and Minimally Important Difference (MID) (the smallest difference in a score that is considered to be meaningful or important), of the two-disease specific PROs: the Treatment Outcome Score (TOS) and the Mean Symptom Complex Severity (MSCS) score. The TOS is a composite measure that evaluates changes in symptoms in response to treatment based on a scale of 100 to -100 (100=significant improvement through to -100=significant worsening) and taking into account symptom severity at baseline. The MSCS score is a point-in-time assessment of individual symptom burden that accounts for symptom severity using a score ranging from 0 to 3 (0=normal through to 3=severe) by each symptom location. In addition to demonstrating individual reliability and validity of the TOS and MSCS score, the analysis demonstrated statistically significant correlations between TOS and changes in MSCS scores. The investigators also estimated the minimum scores that demonstrate a clinically meaningful improvement for both the TOS and change in MSCS score based on the MID (30 points for TOS at 4 hours post-dosing and -0.30 points for change from baseline in MSCS score at 4 hours post-dosing).

“As an HAE-treating physician, I know well the importance of fully understanding the overall impact and experience of an HAE attack,” said Dr. Martha V. White of the Institute for Asthma and Allergy in Wheaton, Maryland and study co-author, “I believe these two instruments – TOS and MSCS – represent highly relevant and robust efficacy measures for evaluating HAE attacks and the effect of treatment.”

About HAE

Hereditary angioedema (HAE) is a rare, genetic, acute inflammatory condition characterized by episodes of severe, often painful swelling affecting the extremities, the gastrointestinal tract, the genitalia, and in potentially life-threatening cases, the larynx. Attacks are unpredictable and range in progression and severity; an acute episode may include swelling symptoms in one or more anatomical sites. 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.

About Dyax

Dyax is focused on advancing novel biotherapeutics for unmet medical needs, with an emphasis on inflammatory and oncology indications. Dyax utilizes its proprietary drug discovery technology to identify antibody, small protein and peptide compounds for clinical development. Dyax's lead product candidate is DX-88 (ecallantide), a recombinant small protein that is currently being evaluated for its therapeutic potential in two separate indications. On June 1, 2009, Dyax submitted a response to the FDA's Complete Response letter regarding the review of Dyax's Biologics License Application (BLA) of DX-88 for the treatment of hereditary angioedema (HAE). The FDA accepted the submission and assigned Dyax's BLA a new Prescription Drug User Fee Act (PDUFA) action date of December 1, 2009. DX-88 has orphan drug designation in the U.S. and E.U., as well as Fast Track designation in the U.S., for this indication. Additionally, DX-88 is being evaluated in two Phase 2 trials for the reduction of blood loss during on-pump cardiothoracic surgery (CTS), which are being conducted by Dyax's partner, Cubist Pharmaceuticals. Dyax licensed to Cubist the intravenous formulation of DX-88 for surgical indications in North America and Europe. DX-88 and other compounds in Dyax's pipeline were identified using its patented phage display technology, which rapidly selects compounds that bind with high affinity and specificity to therapeutic targets. Dyax 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

Dyax Disclaimer

This press release contains forward-looking statements, including statements regarding Dyax's patient reported outcome measures used for its HAE program and the prospects for regulatory filings and approvals for DX-88. 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 prospects for therapeutic benefits and treatment advantages of DX-88 for HAE and include the risks that: DX-88 could take a significantly longer time to gain regulatory approval than Dyax expects or may never gain approval; others may develop technologies or products superior to DX-88 or that are on the market before DX-88; DX-88 may not gain market acceptance; Dyax is dependent on the expertise, effort, priorities and contractual obligations of third parties in the manufacture, marketing, sales and distribution of DX-88; and other risk factors described or referred to Item 1A, “Risk Factors” 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 registered trademarks of Dyax Corp.



Contact: Dyax Corp.
Ivana MagovÄ?ević-Liebisch, 617-250-5759
Executive Vice President Corporate Development
and General Counsel
Nicole Jones, 617-250-5744
Director, Investor Relations and
Corporate Communications


Posted: September 2009