Recombinant Human C1 Inhibitor (Conestat Alfa) In the Treatment of Angioedema Attacks in Hereditary Angioedema

Conestat alfa is a recombinant human Cl inhibitor used in the treatment of angioedema attacks in patients with hereditary angioedema (HAE). Patients with type 1 or II HAE have a deficiency in functional Cl inhibitor, which is an important regulator of complement and contact system activation. The therapeutic efficacy of conestat alfa in the treatment of angioedema attacks in patients with HAE was evaluated in two similar randomized, double-blind, placebo-controlled trials conducted in North America and Europe. The randomized controlled phases of both studies were closed after interim analyses provided compelling evidence of statistically significant positive efficacy findings and showed no apparent adverse safety findings. Results of the pooled analysis of the two trials showed that conestat alfa provided significantly faster initial relief of symptoms than placebo. The median time to the beginning of relief of symptoms (primary endpoint) was 66 minutes with conestat alfa 100 units/kg, 122 minutes with conestat alfa 50 units/kg, and 495 minutes with placebo. Conestat alfa was also statistically superior to placebo for the secondary endpoint of median time to minimal symptoms, with values of 266, 247, and 1210 minutes for the respective treatment groups. On the basis of data from open-label extension studies and integrated analyses of clinical trial data, conestat alfa has demonstrated efficacy in the treatment of repeated HAE attacks and in patients with potentially life-threatening HAE attacks with involvement of the upper airways. Conestat alfa was generally well tolerated in clinical trials, with the most frequently reported adverse event being headache. In the two randomized controlled trials, headache and vertigo were the only adverse events deemed to be related to study treatment.