Successful Long-Term Subcutaneous Prophylaxis of Hereditary Angioedema – Case Study
Hereditary angioedema (HAE), arising from a deficiency of C1 inhibitor (C1-INH), clinically manifests as swelling of the subcutaneous tissue and mucous membranes. The standard prophylactic therapy consists of intravenous (i.v.) substitution of C1-INH. We present a case study of successful long-term subcutaneous (s.c.) prophylaxis in a patient who had to discontinue i.v. prophylaxis.
Introduction
The strategy for treating hereditary angioedema relies on the therapy of acute attacks (s.c. application of a bradykinin B2 receptor blocker, icatibant). In symptomatic patients where adequate control is not achieved with on-demand therapy, long-term prophylaxis, i.e., intravenous substitution of C1-INH, is indicated. Based on the results of a recent prospective double-blind placebo-controlled study, long-term subcutaneous prophylaxis (at a dose of 40 or 60 IU C1-INH/kg body weight) has also been approved.
Case Description
A 69-year-old patient was diagnosed with and laboratory-confirmed HAE type 1 (C1-INH activity 22%; C1-INH concentration 0.10 g/l) 20 years ago. The clinical course of the disease was evaluated using the AE-QoL questionnaire (Angioedema Quality of Life Questionnaire), and the patient also documented all attacks, subjectively grading them as mild, moderate, or severe, and recorded their triggers (infection, psychological or physical stress).
Due to frequent attacks (an average of 4.3/month) and their risky localization (upper respiratory tract mucosa), long-term intravenous prophylaxis with C1-INH was initiated using a venous port at a dose of 1000 IU 2× per week, and subsequently increased to 3× per week due to persistent attacks. The patient and his wife were also trained in the subcutaneous administration of 30 mg of icatibant in the event of an acute attack. During the 6 months of prophylactic therapy, the patient recorded 11 attacks (an average of 1.8/month); 3 were rated as mild, 7 as moderate, and 1 as severe, mainly in the abdominal area, with none affecting the upper respiratory tract mucosa. The patient reported an improvement in quality of life (14.7% in AE-QoL).
After a year of prophylaxis, however, an infection developed at the port site, resulting in sepsis, and the port was subsequently explanted. Due to poor peripheral venous access, intravenous prophylaxis had to be discontinued. Over the next 3 months, the patient recorded 13 acute attacks (3 mild, 6 moderate, and 4 severe, with 2 manifesting as swelling in the upper respiratory tract mucosa) and reported a worsening of quality of life (41.2% in AE-QoL).
Subsequently, long-term subcutaneous prophylaxis was initiated at a dose of 1500 IU C1-INH administered 3× per week. Over 4 months, the frequency of attacks decreased to 1/month. Over 16 months of prophylaxis, 13 attacks were reported (an average of 0.8/month), with none rated as severe or affecting the upper respiratory tract mucosa. The patient further reported an improvement in quality of life (8.8% in AE-QoL), no adverse side effects were reported, and there was a reduced need for s.c. administration of icatibant.
Conclusion
Long-term subcutaneous prophylactic self-administration of C1 inhibitor in a patient with hereditary angioedema for 16 months was found to be well-tolerated and effective. The patient also reported an improved quality of life.
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Source: Hahn J., Nordmann-Kleiner M., Trainotti S. et al. Successful long-term prophylactic treatment with subcutaneous C1 esterase inhibitor in a patient with hereditary angioedema. J Pharm Pract 2020; 33 (6): 907–911, doi: 10.1177/0897190019857407.
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