Older patients with hereditary angioedema (HAE) related to C1-esterase inhibitor (C1-INH) deficiency treated with a subcutaneous injection of the C1-INH had fewer attacks than pre-study levels, according to results of an open-label extension of the COMPACT trial (ClinicalTrials.gov Identifier: NCT01912456) published in Annals of Allergy, Asthma and Immunology.

Patients with frequent HAE attacks, defined as >4 attacks during 2 consecutive months, were treated with a twice weekly subcutaneous injection of the C1-INH 40 IU/kg or 60 IU kg for 52 to 140 weeks. . Safety end points and efficacy outcomes were evaluated for patients aged ≥65 and <65 years. The primary study outcomes were the percentage of patients with <1 attack per 4-weekperiod, and the percentage of responders, defined as having ≥50% reduction in HAE attacks compared to baseline levels.

Of the 126 study participants, 10 were ≥65 years. Of these 10 participants, 8 had multiple comorbidities, and 6 were taking ≥5 non-HAE–related drugs concomitantly. Following treatment with subcutaneous injection of the C1-INH, 6 of 9 evaluable patients were considered responders, with ≥50% reduction in HAE attacks compared with baseline. Adverse events included injection-site bruising, injection-site pain, urinary tract infection, and diarrhea. However, there were no thromboembolic events or cases of anaphylaxis reported.

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“The results of this post hoc analysis demonstrated that C1-INH (SC) [subcutaneous] provides effective, safe, and well-tolerated long-term prophylaxis of angioedema attacks in patients ≥65 years old with C1-INH-HAE in spite of multiple comorbidities and polypharmacy,” the study authors wrote. “Additional analyses using a broader definition of ‘older’ (eg, ≥60 years or ≥55 years) adults are planned.”

Disclosure: This clinical trial was supported by CSL Behring. Please see the original reference for a full list of authors’ disclosures.


Bernstein JA, Schwartz L, Yang W, et al. Long-term safety and efficacy of subcutaneous C1-inhibitor in older patients with hereditary angioedema [published May 12, 2020]. Ann Allergy Asthma Immunol. doi:10.1016/j.anai.2020.05.015