Efficacy and Safety of BCX7353 to Prevent Angioedema Attacks in Subjects With Hereditary Angioedema

Efficacy was evaluated by the number of acute angioedema attacks. To ensure that consistent, objective assessments were used in accepting subject-reported attack data, a panel of expert physicians in the treatment of HAE patients adjudicated all subject-reported attacks prior to their inclusion in primary efficacy analyses.

Assessment of the proportion of subjects who had no HAE attacks during the entire dosing period

A prespecified secondary endpoint analyzed confirmed attacks by anatomical location; abdominal HAE attacks included any abdominal symptoms (i.e. swelling in the stomach/gut, or any symptoms of nausea, vomiting, or abdominal pain)

A prespecified secondary endpoint analyzed confirmed attacks by anatomical location; peripheral attacks included any with peripheral symptoms only (i.e. peripheral swelling or erythema marginatum).

A prespecified secondary endpoint analyzed the number of attacks requiring treatment with acute HAE medication (Berinert, Firazyr, Cinryze or Ruconest)

Activity of disease (i.e. disease severity) was assessed using a modified Angioedema Activity Score (AAS). The relevant endpoint for this study was the total modified AAS score, defined as the sum of the individual scores for 4 AAS domains (daily activities, appearance, physical discomfort, and overall severity) for all subject-reported attacks reported during the treatment period. Individual domain scores were based on answers to questions each of which had 4 possible responses scored 0-3 (0 - no impact; 1-3 - increasing levels of impact). The total modified AAS score per attack could range from 0 to 12; lower scores & higher scores represent lower & higher disease activities, respectively. However, the overall total modified AAS score reported for this study included the total scores for all subject-reported attacks, therefore the upper limit of the range was subject-specific. The statistical analysis of the total modified AAS scores for the treatment period is presented below.

Quality of Life (QoL) specific to hereditary angioedema (HAE) was assessed at baseline and Day 29 by a questionnaire (i.e. AE-QoL) consisting of 17 questions that spanned 4 domains (functioning, fatigue/mood, fear/shame, and nutrition). Each AE-QoL question had 5 answer options (scored 1-5), with lower and higher scores indicting less and more adverse impact, respectively. Per-subject scores for each domain were computed using the appropriate scoring algorithm applied to the question response scores for each domain. Per-subject total scores (including all 4 domains) were similarly computed using the question response scores for all 17 questions. The outputs from the scoring algorithm were normalized on a scale ranging from 0 (less adverse impact) to 100 (most adverse impact). The statistical analysis of the AE-QoL total score change from baseline to Day 29 is presented below.

The Depression, Anxiety & Stress Scale (DASS) was used to measure the negative emotional states of depression, anxiety & stress. This assessment was based on a DASS questionnaire administered at baseline, Day 14 & Day 29. The questionnaire consisted of 3 DASS scales (depression, anxiety & stress) containing 14 items each on a scale of 0 to 3 (0, did not apply to me at all; 1, applied to me to some degree/some of the time; 2, applied to me to a considerable degree/a good part of the time; 3, applied to me very much or most of the time). Per-subject scores for the depression, anxiety & stress scales were obtained by summing the scores for the appropriate questionnaire items for the respective category. Total DASS scores were then derived as the sum of the 3 individual scales & ranged from 0 to 126. Higher & lower total scores are associated with more & less adverse impact, respectively. The statistical analysis of the total DASS score change from baseline to Day 29 is presented below.