Plasma-derived C1-INH concentrate is highly effective in the treatment of patients with acquired angioedema due to C1-inhibitor deficiency — acting fast and significantly shortening attack duration, a study found.
The findings were presented at the 2019 American Academy of Allergy, Asthma and Immunology (AAAAI) Annual Meeting, in a communication titled “Angioedema Due To Acquired C1-Inhibitor Deficiency: Spectrum And Treatment With C1-Inhibitor Concentrate.”
Acquired angioedema (AAE) due to C1-inhibitor (C1-INH) deficiency (AAE-C1-INH) is a rare immune system disorder that causes recurrent episodes of swelling of the face or body, often lasting several days.
The swelling happens because C1-INH levels are too low. This is due to either an abnormal immune system that affects the production of this protein, or because an autoimmune condition led to the production of antibodies against the individual’s own C1-INH proteins.
In the absence of enough C1-INH, levels of the inflammatory molecule bradykinin rise, causing blood vessels in the deep layers of the skin to widen. This allows fluid to flow into the tissues, which causes swelling.
There is limited research on the prevalence of other disease types in people with AAE-C1-INH. To learn more, a team of German researchers set out to conduct a study describing the occurrence of associated diseases in this group of patients. They also examined the efficacy of treatment with plasma-derived C1-INH concentrate for swelling attacks.
Plasma-derived C1-INH concentrate — which includes CSL Behring‘s Berinert and Shire‘s Cinryze — is an option for treatment of acute swelling attacks in hereditary angioedema patients who also lack the C1-INH protein.
Researchers examined medical records of 44 people with AAE-C1-INH. For 32, there was information on the duration of swelling attacks both before and after treatment.
Looking at disorders associated with acquired angioedema, researchers found that nearly half the patients (47.7%) had monoclonal gammopathy of undetermined significance, a precursor condition of multiple myeloma.
Non-Hodgkin’s lymphoma was found in 27.3% of the individuals — 75% of whom were diagnosed with lymphoma due to the angioedema attacks. The findings also showed that 11.4% had anti-C1-INH autoantibodies only, and 4.5% had other conditions. Only 9.1% of patients had no associated disorders.
Importantly, treatment with plasma-derived C1-INH concentrate shortened swelling attacks by an average of 54.4 hours. Researchers also noted that the earlier the attack was treated, the shorter the time between injection and disappearance of symptoms.
Overall, a total of 97.7% of attacks were effectively treated with plasma-derived C1-INH, as assessed by the patients themselves. But the treatment was slightly more effective in individuals without antibodies to the C1-INH protein (99.4%), compared to those with such antibodies (93.8%).
For each effectively treated attack, the average dose was 1,238.4 units in patients with anti-C1-INH autoantibodies, and 510.2 units in those without autoantibodies.
The investigators concluded that plasma-derived C1-INH “is highly effective in treating AAE-C1-INH patients.”
“It reduces attack duration and is fast-acting. It is also effective in the vast majority of attacks in patients with anti-C1-INH autoantibodies,” they said.