given as three 1mL subcutaneous injections.

The overall response assessment is a patient-reported assessment of global response to therapy. Patients are asked to perform an overall response assessment at regular intervals, relative to baseline. Patients were asked "overall how are you feeling" compared to how they felt before study drug. Answer options were "a lot worse", "a little worse", "same", "a little better" or "a lot better or resolved". Significant improvement was the first time that the patient responded to the assessment as "a little better or resolved".

Treatment Outcome Score (TOS) is a validated, comprehensive measure of symptom response to treatment. At 4 hours , patient assessment of response characterized by their change from baseline in symptom severity and collected by anatomic site of attack involvement, was recorded on a categorical scale (significant improvement [100] to significant worsening [-100]). The response at each anatomic site was weighted by baseline severity and then the weighted scores across all involved sites were averaged to calculate the TOS. Clinically meaningful improvement was indicated by a TOS of 30 or higher.

The Mean Symptom Complex Severity (MSCS) score is a validated, comprehensive point-in-time measure of symptom severity. At baseline and 4 hours, patients rated the severity on a categorical scale (0 = normal, 1 = mild, 2 = moderate, 3 = severe) for symptoms at each affected anatomical location. Ratings were averaged to obtain the MSCS score. A decrease in MSCS score reflected an improvement in symptoms; clinically meaningful improvement was indicated by a reduction in the score of 0.30 or more.

The overall response assessment is a patient-reported assessment of global response to therapy. Patients are asked to perform an overall response assessment at regular intervals, relative to baseline (ie,immediately before treatment) using the following 5-category scale from significant improvement (Score = 100)to significant worsening (Score = -100)

Patients not treated in the double-blind part but treated with ecallantide in the repeat-dosing part. One patient was omitted from analysis in the intent-to-treat and per-protocol populations due to the loss of the data for the 4-hour post-dose assessments during treatment episode 1.

Total of all reporting groups

Patients treated with ecallantide in the double-blind part.

Patients treated with placebo in the double-blind part.

Mean Symptom Complex Severity (MSCS) score is a validated, comprehensive point-in-time measure of symptom severity. At baseline and 4 hours, patients rated the severity on a categorical scale (0 = normal, 1 = mild, 2 = moderate, 3 = severe) for symptoms at each affected anatomical location. Ratings were averaged to obtain the MSCS score. A decrease in MSCS score reflected an improvement in symptoms; clinically meaningful improvement (minimally important difference) was indicated by a reduction in the score of 0.30 or more.

ITT as treated: two patients randomized on the same day at the same center were administered treatment opposite to their randomized treatment assignments. Data were analyzed based on their actual treatment received. Imputation was used to account for emerging symptoms and medical intervention. Best possible score = 0.0; worst possible score = 3.0.

Patient-reported severity of symptom complexes at baseline, by symptom complex and treatment group. Patients were to have at least one symptom complex that was moderate or severe. Patients could present with multiple symptom complexes, some of which could be mild. Mild=noticeable but do not impact daily living activities; Moderate=treatment or intervention is highly desirable and activities of daily living are impacted; Severe=require treatment or intervention due to inability to perform activities of daily living. The results are for number of patients with symptom complexes including mild, moderate and severe, provided the patients have at least one symptom complex that was moderate or severe

Treatment Outcome Score (TOS) is a validated, comprehensive measure of symptom response to treatment. At 4 hours , patient assessment of response characterized by their change from baseline in symptom severity and collected by anatomic site of attack involvement, was recorded on a categorical scale (significant improvement [100] to significant worsening [-100]). The response at each anatomic site was weighted by baseline severity and then the weighted scores across all involved sites were averaged to calculate the TOS. Clinically meaningful improvement was indicated by a TOS of 30 or higher.

Treatment episode 1 contains data only from those participants who were new patients in the repeat-dosing part. Treatment episode 2 and beyond contain data pooled from patients treated in the double-blind part (ecallantide or placebo) and the repeat-dosing part. Data imputation was used to account for emerging symptoms and medical intervention.

The Mean Symptom Complex Severity (MSCS) score is a validated, comprehensive point-in-time measure of symptom severity. At baseline and 4 hours, patients rated the severity on a categorical scale (0 = normal, 1 = mild, 2 = moderate, 3 = severe) for symptoms at each affected anatomical location. Ratings were averaged to obtain the MSCS score. A decrease in MSCS score reflected an improvement in symptoms; clinically meaningful improvement was indicated by a reduction in the score of 0.30 or more.

Treatment episode 1 contains data only from those participants who were new patients in the repeat-dosing part. Treatment episode 2 and beyond contain data pooled from patients treated in the double-blind part (ecallantide or placebo) and the repeat-dosing part. Data imputation was used to account for emerging symptoms and medical intervention.

The overall response assessment is a patient-reported assessment of global response to therapy. Patients are asked to perform an overall response assessment at regular intervals, relative to baseline. Patients were asked "overall how are you feeling" compared to how they felt before study drug. Answer options were "a lot worse", "a little worse", "same", "a little better" or "a lot better or resolved". Significant improvement was the first time that the patient responded to the assessment as "a little better or resolved".

ITT as treated. Patients not reporting significant improvement before 4 hours were censored at 4 hours. Patients receiving additional HAE therapy within 4 hours were censored at the time of the medical intervention. The time to significant improvement is not provided in this display as the median time for placebo was not reached by 4 hours.

The overall response assessment is a patient-reported assessment of global response to therapy. Patients are asked to perform an overall response assessment at regular intervals, relative to baseline (ie,immediately before treatment) using the following 5-category scale from significant improvement (Score = 100)to significant worsening (Score = -100)

Patients not reporting significant improvement before 4 hours were censored at 4 hours. Patients receiving additional HAE therapy within 4 hours were censored at the time of the medical intervention. The time to significant improvement is not provided in this display as the interquartile range (IQR) was not reached by 4 hours for most episodes.

Patients treated with placebo in the double-blind part only.

All patients treated with ecallantide in the repeat-dosing part, regardless of whether they were treated previously in the double-blind part or not. All adverse events reported in all repeat-dosing episodes are included. Patients reporting more than 1 AE with the same preferred term are counted only once for that preferred term.