Sustained response of recombinant human C1 esterase inhibitor for acute treatment of hereditary angioedema attacks

BackgroundSymptoms of hereditary angioedema (HAE) attacks can recur soon after initial treatment; the durability of response for recombinant human C1 esterase inhibitor (rhC1INH) treatment is unknown.ObjectiveTo examine the efficacy and durability of rhC1INH for acute HAE attacks.MethodsIn this pooled post hoc analysis of 2 trials, patients with type I or II HAE (functional C1INH levels <50% of normal) and a baseline visual analog scale score of at least 50 mm were included if they had received at least 1 intravenous dose of 50 IU/kg of rhC1INH. Response was defined as symptom relief within 4 hours after treatment with persistence (≥20-mm decrease in visual analog scale scores [0 mm {“no symptoms at all”} to 100 mm {“extremely disabling”}] at 2 consecutive time points) during the 4 hours. Durability was the response without an increase of at least 20 mm in the minimum post-treatment visual analog scale score up to 24 hours. Recurrence and new attack symptoms were determined for patients with 72-hour post-treatment data.ResultsData were analyzed for 127 patients treated with 50 IU/kg of rhC1INH in 2 studies. Most attacks (90.7%) responded within 4 hours, with differences in response rates among attack locations (61.5%-94.4%). The median time to the beginning of symptom relief was 75.0 minutes (95% confidence interval 65.0-80.0). No relapse occurred during 24 hours for attacks that initially responded. Only 7.1% of attacks were associated with symptom recurrence within 72 hours of initial rhC1INH treatment.ConclusionThis integrated analysis supports the efficacy of rhC1INH for treatment of acute HAE across multiple attacks, with a sustained response for at least 3 days.Trial RegistrationClinicalTrials.gov Identifiers: NCT00225147 and NCT00262301.