Long-term Safety and Efficacy of Subcutaneous C1-Inhibitor in Older Patients With Hereditary Angioedema.

Background Patients ≥65 years old with hereditary angioedema (HAE) due to C1-inhibitor (C1-INH) deficiency may have an altered response to treatment and be at higher risk for treatment-related adverse events (AEs) due to comorbidities and polypharmacy. Objective Investigate the safety and efficacy of subcutaneous (SC) C1-INH in patients ≥65 years old treated in an open-label extension of a phase 3 trial. Methods Eligible patients (≥4 attacks over 2 consecutive months) were randomized to receive twice-weekly C1-INH (SC) 40 IU/kg or 60 IU/kg for 52 to 140 weeks. Safety endpoints and efficacy outcomes were evaluated for patients aged ≥65 and Results Of 126 subjects treated, 10 were ≥65 years old (mean age [range], 68 [65-72 years]). Eight of 10 subjects had multiple comorbidities; 6/10 were taking >5 non-HAE-related drugs concomitantly. AEs occurring in >1 subject included injection-site bruising (n = 2, related), injection-site pain (n = 2, related), urinary tract infection (n = 2, unrelated), and diarrhea (n = 2, unrelated). No thromboembolic events or cases of anaphylaxis were reported. Two subjects ≥65 years old experienced unrelated serious AEs (dehydration and hypokalemia in one and pneumonia and an HAE attack leading to hospitalization in another). Six of 9 evaluable subjects were responders, with ≥50% reduction in HAE attacks versus pre-study; 6/10 had Conclusion C1-INH (SC) was well tolerated and effective in the management of HAE in these subjects ≥65 years old with multiple comorbid conditions and polypharmacy.