Practicalities of a reduced volume formulation of a C1-INH concentrate for the treatment of hereditary angioedema: real-life experience

Background: Hereditary angioedema (HAE) due to C1 esterase inhibitor (C1-INH) deficiency is characterized by recurrent swelling attacks that can be life-threatening if left untreated. Prompt treatment is vital during acute attacks; plasma-derived C1-INH (Berinert (R)) is one treatment currently licensed for the intravenous treatment of acute HAE attacks in adults, adolescents and children. A new, volume-reduced formulation, of C1-INH is currently available which aims to reduce the time to treatment, and provide greater convenience to patients and healthcare professionals. Here we compare the clinical experience of the reduced volume 1500 IU vial with multiple 500 IU vials. Methods: HAE patients treated with C1-INH at the Royal London Hospital were selected to take part in this assessment. Included patients were aged 10-65 with moderate to severe HAE requiring high doses of C1-INH. The practicalities of the reduced 1500 IU vial compared with multiple 500 IU vials were assessed, including preparation and administration time, training to self-administer time and several quality of life aspects. Results: Twenty-three patients participated in this study. Twenty-one patients were previously treated with C1-INH (Berinert (R)) 500 IU for 1-14years prior to switching to the 1500 IU vial format, two patients were naive to C1-INH (Berinert (R)). Preparation and administration of C1-INH (Berinert (R)) 1500 IU was faster than an equivalent dose with multiple 500 IU vials (11 and 17 min, respectively) and also required less time to train to self-administer (45 and 55 min, respectively). Overall, patients rated the 1500 IU vial format higher in all assessed aspects than the 500 IU format, including preparation, administration, training, travel and storage. Nonetheless, reconstitution of the 1500 IU vial was noted more difficult, requiring gentle mixing to fully dissolve prior to intravenous injection. Patients remained stable on C1-INH (Berinert (R)) 1500 IU; two patients switched back to multiple 500 IU vials due to headaches and preference for a larger volume. Conclusions: The volume-reduced C1-INH concentrate (Berinert (R)) 1500 IU is a practical and convenient alternative to multiple 500 IU vials for the treatment of HAE, which provides patients with more control and independence over their disease owing to a simpler to administer treatment.