EDEMA4 study results of KALBITOR for treatment of acute attacks of HAE published

Dyax Corp. (NASDAQ: DYAX) announced today the publication of results from its second Phase 3, placebo-controlled trial, known as EDEMA4^®, evaluating KALBITOR (ecallantide) for the treatment of acute attacks of hereditary angioedema (HAE). The results, published in the June 2010 issue of the Annals of Allergy, Asthma, and Immunology, indicate that KALBITOR is effective in ameliorating HAE attacks, resolving associated symptoms and preventing attack progression. KALBITOR, a selective plasma kallikrein inhibitor that was discovered and developed by Dyax, is available in the U.S. for the treatment of acute attacks of HAE in patients 16 years of age and older.

“Since acute attacks of HAE tend to worsen over the first 24 hours, treatment with an effective therapy such as Kalbitor is important for symptom management. EDEMA4 data also suggest that the benefit seen with KALBITOR begins a few hours after dosing.”

KALBITOR treatment resulted in statistically significant improvement of symptoms over placebo at four hours post dosing, as measured by two HAE-specific, patient-reported outcome measures: change in Mean Symptom Complex Severity (MSCS) score (KALBITOR = -0.8 versus placebo = -0.4;>

The overall safety profile of KALBITOR observed in EDEMA4 was similar to that of placebo. The most common treatment-emergent adverse events (nausea, headache, and dizziness) were mild or moderate and occurred at a similar proportion in both the KALBITOR and placebo-treated groups. No serious adverse events were reported in the KALBITOR-treated group and no KALBITOR-treated patients developed symptoms suggestive of hypersensitivity.

"The EDEMA4 study has demonstrated that KALBITOR reduces symptoms of acute attacks of swelling associated with HAE within just 4 hours post dosing, sustaining the effect at 24 hours post dosing," stated Dr. Robyn J. Levy, of the Family Allergy & Asthma Research Center in Atlanta, Georgia and lead author and principal investigator of the EDEMA4 trial. "Since acute attacks of HAE tend to worsen over the first 24 hours, treatment with an effective therapy such as Kalbitor is important for symptom management. EDEMA4 data also suggest that the benefit seen with KALBITOR begins a few hours after dosing."

Mean TOS scores at 1, 2, and 3 hours post dosing were also analyzed. The KALBITOR treatment group experienced a clinically meaningful trend toward greater improvement (represented by increasing TOS) versus the placebo group at 1 hour (TOS: KALBITOR = 20.7 versus placebo = 8.2;>

Emerging symptoms were observed more frequently among the placebo-treated patients (14.6%) compared to the KALBITOR-treated group (4.2%). Moreover, of these, three placebo-treated patients reported emerging laryngeal symptoms, while zero emerging laryngeal symptoms were reported from the KALBITOR-treated patients.

While in EDEMA4 no serious adverse events or symptoms suggestive of hypersensitivity were reported in the KALBITOR-treated group, in the overall KALBITOR clinical program, hypersensitivity was reported after administration with KALBITOR. As part of product approval, Dyax has implemented a Risk Evaluation and Mitigation Strategy (REMS) program, consisting of a Medication Guide and communication plan. The goal of the REMS is to communicate the risk of anaphylaxis and the importance of distinguishing between a hypersensitivity reaction and HAE attack symptoms.