Dyax has announced positive topline results from its Phase III, placebo-controlled trial, EDEMA3, for its lead product candidate DX-88, for hereditary angioedema (HAE).

DX-88 (ecallantide), an internally discovered, recombinant, plasma kallikrein inhibitor, is in clinical trials for the treatment of acute attacks of HAE, a rare genetic disease characterized by episodes of acute swelling and inflammation. Statistically significant results were achieved for both the primary and secondary endpoints in the EDEMA3 trial.

EDEMA3, a 72-patient, placebo-controlled, multicenter, Phase III trial, was conducted at 34 sites in the U.S., Europe, Canada and Israel. The primary objective of EDEMA3 was to determine the efficacy and safety of the fixed 30-mg subcutaneous (SC) dose of DX-88 for patients suffering from moderate to severe acute HAE attacks. The trial had two phases: a double-blind, placebo-controlled phase and a repeat-dosing phase. In the first phase, HAE patients received either a single 30-mg SC dose of DX-88 or placebo. After patients received one treatment in the placebo-controlled portion of the study, they were eligible for the second, open-label phase of the study, where they receive repeat dosing with SC DX-88 for any subsequent attacks.

The primary endpoint, symptom improvement at four hours measured by a treatment outcome score developed for HAE attacks, as well as the two secondary endpoints, demonstrated statistical significance. Time to significant improvement in overall response had a median time of 149 minutes for the DX-88 group versus greater than four hours for the placebo group. The overall safety results showed that DX-88 continues to be well tolerated. There were no drug-related serious adverse events.

"Based on the topline results of this study, the extensive clinical data collected to date and the pending completion of the EDEMA4 confirmatory trial already under way, we believe we will be well positioned to apply for regulatory approval to bring to market this much needed therapy for the HAE patient community," Henry Blair, chairman and CEO of Dyax, said.