The results from the Phase III, double blind, placebo-controlled trial, IMPACT, showed that patients treated with 20U/kg b.w. C1-INH experienced a highly significant reduction in time to onset of relief of symptoms of hereditary angioedema (HAE) attacks compared to placebo. In addition, all secondary endpoints of the trial have shown significant positive results.
The trial was conducted globally in more than 45 centers in 15 countries, enrolling 125 patients, and is reported to be the largest trial ever conducted in HAE. For the first time, a dose comparison study was conducted for a human C1-inhibitor (C1-INH) comparing 20U/kg b.w. and 10U/kg b.w. in a randomized, placebo-controlled, double-blind study design.
The primary objective was to show that C1-INH shortens the time to onset of relief of symptoms of abdominal or facial HAE attacks. The primary endpoint was time between start of C1-INH administration and onset of relief of symptoms from abdominal or facial attacks as determined by the subject’s assessment.
The secondary endpoint, that is the proportion of subjects with increased intensity of clinical HAE symptoms between two and four hours after start of study drug administration compared to baseline, also showed significant improvement, as did time to the complete resolution of HAE symptoms.
Hilary Longhurst, investigator of the IMPACT trial, said: “The successful completion of this trial confirms longstanding observations made from the administration of more than 300,000 treatments of C1-INH concentrate in Europe. We are delighted that it will now be submitted for registration in the UK.”