Nanofiltered C1 Inhibitor Concentrate for Treatment of Hereditary Angioedema

Hereditary angioedema is one of those conditions that frightens even seasoned emergency physicians, and would be one of the last conditions I would ever want to encounter (again) in an outdoor or wilderness setting away from advanced medical care capabilities, in particular the ability to start an intravenous line to administer medications and having proximity to all the tricks and tools possible to manage a compromised airway. Persons who suffer from hereditary angioedema can rapidly develop painful swelling of the soft tissues of the face. If the airway (face, tongue, and lip swelling) is involved, the situation can rapidly become life threatening.

Hereditary angioedema is caused by a deficiency of a substance known as C1 inhibitor. So, it is logical that one would try to treat it by replacing this substance. In an article in the New England Journal (2010;363:513-22) entitled “Nanofiltered C1 Inhibitor Concentrate for Treatment of Hereditary Angioedema,” Bruce Zuraw, MD and his colleagues reported on
two clinical trials to evaluate nanofiltered C1 inhibitor concentrate in the management of hereditary angioedema. One trial evaluated intravenous infusion of the concentrate to treat acute attacks of angioedema, while the other evaluated its use as twice-weekly injections to reduce the number of attacks of angioedema during the treatment periods (12 weeks).

The results were encouraging on both counts. In the first study, the median time to the onset of unequivocal relief from an attack was 2 hours in the treated subjects versus 4 hours in the untreated subjects. In the second study, the number of attacks was approximately halved by using the infusion for prophylaxis. Additional benefits in the second study were reductions in the severity and duration of attacks, and in the total number of days with swelling.

So, while this is only my inference from the studies, it seems that persons with C1 inhibitor deficiency contemplating being in a situation far from medical care would wish to avail themselves of prophylactic nanofiltered C1 inhibitor concentrate infusions.