ATLANTA, GA—Recombinant human C1 esterase inhibitor (rhC1INH) reduces time to symptomatic relief from acute hereditary angioedema (HAE) attacks, according to a pooled analysis of data from 2 randomized, double-blind, placebo-controlled trials. The findings were presented at the 2017 AAAAI Annual Meeting. 

“rhC1INH 50 IU/kg was efficacious in shortening the time to the beginning of symptom relief of acute HAE attacks, regardless of attack location,” reported lead study author James W. Baker, MD, of Baker Allergy Asthma and Dermatology, in Lake Oswego, OR, and colleagues.

Hereditary angioedema is a genetic disorder that can trigger very painful mucosal and cutaneous angioedema of the abdomen, hands, feet, mouth, and pharyngeal-laryngeal region. Clinical trials have shown that rhC1INH can relieve symptoms overall but efficacy for individual anatomies has not been “thoroughly explored,” Dr. Baker noted.

Participants in the two trials included in the analysis were ≥12 years old and received either rhC1INH 50 IU/kg or placebo. Hereditary angioedema attacks were included in the pooled analysis if overall severity score reached at least 50mm on a 100mm visual analog scale (VAS). A total of 412 attacks were analyzed. Regardless of anatomic site, symptomatic relief was achieved more rapidly among patients receiving rhC1INH than those who were administered placebo. 

For patients experiencing abdominal attacks, symptomatic relief began at a median of 60 minutes (95% CI: 47.0, 62.0) in patients receiving rhC1INH (n=194) vs. 240 minutes (95% CI: 45.0, 720.0) for those receiving placebo (n=15). Patients suffering peripheral attacks, the time to the beginning of symptom relief for patients in the rhC1INH group (n=169) was 105 minutes vs. 303 minutes for patients in the placebo group (n=17). Symptoms relief from oro-facial-pharyngeal-laryngeal attacks began at 64.5 minutes for patients in the rhC1INH group (n=36) compared to 306 minutes for patients in the placebo group (n=6). Time to symptomatic relief could not be determined for the 2 patients in the placebo group who experienced facial attacks but relief began at 158 minutes (95% CI: 90, 330) for patients in the rhC1INH group (n=24). 

The findings suggest that rhC1INH 50 IU/kg shortens time to start of symptomatic relief from acute attacks and “support the use of rhC1INH across various anatomical attack locations in adults and adolescents with hereditary angioedema,” Dr. Baker said.