A Study of Icatibant (TAK-667) in Japanese Children and Teenagers With Acute Attacks of Hereditary Angioedema

Inclusion Criteria

• In the opinion of the investigator or subinvestigator, the participant's parent or legal guardian is capable of understanding and complying with protocol requirements.
• The participant's parent or the participant's legal guardian is capable of signing and dating a written informed consent form on behalf of the participant prior to the initiation of any study procedures. Written informed assent is also obtained from the participant as much as possible.
• The participant is in Japan and is Japanese; defined as born in Japan and having Japanese parents and Japanese maternal and paternal grandparents.
• The participant is male or female and 2 to =12 kg at the time of the current HAE attack.
• The participant who has a documented and confirmed diagnosis of HAE type I or II. Diagnosis may be based on historical data using the following criteria:
• Family history of angioedema
• Characteristic attack manifestations, recurrent attacks
• Functional complement 1 (C1) esterase inhibitor (C1-INH) deficiency
• In the absence of a family history of angioedema, exclusion of other forms of angioedema (eg. angiotensin converting enzyme (ACE)-induced angioedema, allergic angioedema) based on medical judgement (eg, concomitant medication, response to antihistamines or glucocorticoids, information of genetic mutation).
• If the participant does not have a documented and confirmed diagnosis of HAE type I or II based on historical data, including C1-INH deficiency, the participant's diagnosis must be determined prior to treatment by C1-INH test results which demonstrate a functional C1-INH deficiency.
• HAE type I: Low amount of C1-INH protein and low level of C1-INH activity; HAE type II: Normal or increased amount of C1-INH protein and low level of C1-INH activity
• In the absence of a family history of angioedema, exclusion of other forms of angioedema (eg. ACE-induced angioedema, allergic angioedema) based on medical judgement (eg, concomitant medication, response to antihistamines or glucocorticoids, information of genetic mutation).
• The current HAE attack must be in the cutaneous, abdominal, and/or laryngeal (inclusive of laryngeal and pharyngeal) areas, but no prespecified attack severity criteria are required for treatment.
• The participant commences treatment within 12 hours after the onset of current HAE attack.
• A female participant of childbearing potential who is sexually active with a nonsterilized male partner agrees to use routinely adequate contraception from signing of informed consent throughout the duration of the study, and proves negative in the pregnancy test at screening.

Exclusion Criteria

• The participant will require an intervention to support the airway (eg, intubation, tracheotomy, cricothyrotomy) due to the current HAE attack.
• The participant presents with an HAE attack with laryngeal/upper respiratory tract symptoms which are considered severe in the investigator's clinical judgment and which may necessitate urgent care and/or impede the conduct of study efficacy assessments.
• The participant has a diagnosis of angioedema other than HAE
• The participant has evidence of stroke or coronary artery disease based on medical history at the screening examination or at pretreatment; eg, acute ischemic heart disease, unstable angina pectoris, severe coronary heart disease or congestive heart failure, that in the investigator's judgment would be a contraindication for participation in the trial (New York Heart Association [NYHA] class 3 and 4).
• The participant has received treatment with any pain medication since the onset of the current HAE attack.
• The participant has received replacement therapy (C1-INH products, fresh frozen plasma [FFP]) within 5 days (120 hours) from the onset of the current HAE attack.
• The participant has received treatment with ACE inhibitors within 7 days prior to treatment.
• The participant has used hormonal contraceptive within 90 da