Sustained Response Following Acute Treatment Of Hereditary Angioedema Attacks With Recombinant Human C1 Esterase Inhibitor

Hereditary angioedema (HAE) with C1 esterase inhibitor (C1INH) deficiency is characterized by recurrent attacks of tissue swelling. Recombinant human C1INH (rhC1INH) is effective in improving angioedema symptoms in HAE patients. This post-hoc analysis evaluated durability of response to rhC1INH by assessing the rate of relapse, the use of an additional rhC1INH dose following the initial dose, and new attack occurrences. Data were evaluated from 4 studies on HAE attacks treated with an initial dose of 50 IU/kg rhC1INH. The proportion of attacks treated with an additional dose of rhC1INH was evaluated in studies where this was permitted. Response was defined as ≥20 mm decrease in visual analog scale (VAS) scores at two consecutive time points occurring within 4h, and relapse was defined as response followed by worsening of symptoms within 24h. New attacks occurring within 3 days of treatment were summarized. One hundred twenty seven patients were treated for 290 attacks; 13 of 280 attacks (5%) were treated with an additional dose of 50 IU/kg, while 95% were treated with a single dose. Of the 290 attacks with 24h follow up data, 263 (91%) responded within 4h and none were associated with relapse of symptoms. Of the 280 attacks with 3-day follow up data, 260 (93%) attacks had no new attack symptoms during this time. Treatment with rhC1INH resulted in a high response rate and no relapses within 24h. Most attacks were treated effectively with a single dose, with a low rate of new attacks over a 3-day period.