Dyax' Phase 3 hereditary angioedema clinical program affirms reliability of its novel PROs

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>

“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.”