Improved Quality-of-Life with Subcutaneous C1-inhibitor Prevention in Hereditary Angioedema

Published online: February 23, 2018

Hereditary angioedema with C1-inhibitor deficiency (C1-INH-HAE) is an autosomal dominant inherited chronic condition in which patients experience recurring episodes of debilitating and painful swelling, typically affecting the arms and legs, abdomen, and face. Swelling of the larynx is less common but can be fatal. The physical manifestations of the disease typically impact quality of life (QoL) for patients and their families and can interfere with social activities and work/school productivity. These burdens are compounded further by emotional factors, typically depression and anxiety about future attacks. Over the past decade, a number of new targeted therapies for C1-INH-HAE have come to market which have improved the treatment landscape. Still, recent research findings reveal considerable treatment and disease burden impacting QoL, especially for patients with frequent HAE attacks.

In a recent study published in The Journal of Allergy and Clinical Immunology: In Practice, Lumry and colleagues report on the effect of treatment with a subcutaneous formulation of C1 INH protein (C1-INH[SC]) on various measures of QoL. They analyzed QoL data from the recently reported double-blind, placebo-controlled COMPACT study (N Engl J Med 2017;376:1131-1140). The COMPACT study involved 90 individuals with HAE who experienced at least 2 HAE attacks per month at baseline (before the study began). The study subjects were randomly assigned in a cross-over design to self-administer C1-INH(SC) twice weekly for 16 weeks at a dose of 40 IU/kg or 60 IU/kg, preceded or followed by 16 weeks of twice-weekly placebo injections. If HAE attacks occurred, subjects were treated with rescue HAE medications per usual medical practice. The subjects completed various QoL assessments including the European Quality of Life-5 Dimensions Questionnaire (EQ-5D-3L), the Hospital Anxiety and Depression Scale (HADS), the Work Productivity and Activity Impairment Questionnaire (WPAI), and the Treatment Satisfaction Questionnaire for Medication (TSQM). Assessments were done before, during, and at the end of each treatment period.

Assessments conducted before the study showed generally low levels of anxiety and depression in the study subjects, yet the use of C1-INH(SC) significantly improved scores for anxiety, in particular, compared to the use of placebo injections and treating attacks as they happened. Before the study, the population evidenced notable impairments in work productivity and disruption of non-work activities. Marked improvements were noted on these outcomes while using C1-INH(SC), suggesting that effective prevention of HAE attacks has important QoL benefits with regard to minimizing disruption of work and other activities. Subjects also reported high levels of treatment satisfaction and perceived effectiveness with the treatment used as routine prevention.

This study was the first to evaluate QoL in patients with C1-INH-HAE using self-administered subcutaneous C1-inhibitor as routine prophylaxis. Recently updated expert treatment guidelines for C1-INH-HAE have emphasized restoration of normal QoL as a primary goal of treatment. These findings from the COMPACT study provide strong evidence that subcutaneous C1-INH indeed produces significant and clinically relevant improvement in such measures, most notably improving anxiety and enabling patients with C1-INH-HAE to regain active and productive lifestyles.

The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.

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