Efficacy and Safety of Lanadelumab (SHP643) in Japanese Participants With Hereditary Angioedema (HAE)

Inclusion Criteria:

• Be of Japanese descent, defined as born in Japan and having Japanese parents andJapanese maternal and paternal grandparents.
• The participant is male or female and >= 12 years of age at the time of informedconsent.
• Documented diagnosis of HAE (Type I or II) based upon all of the following:

1. Documented clinical history consistent with HAE (subcutaneous or mucosal,nonpruritic swelling episodes without accompanying urticaria).
2. Diagnostic testing results obtained during screening that confirm HAE Type I orII: C1 inhibitor (C1-INH) functional level <40% of the normal level. Participantswith functional C1-INH level 40-50% of the normal level may be enrolled if theyalso have a C4 level below the normal range. With prior sponsor approval,participants may be retested during the run-in period if results are in congruentwith clinical history or believed by the investigator to be confounded by recentC1 inhibitor use.
3. At least one of the following: age at reported onset of first angioedema symptoms <=30 years, a family history consistent with HAE Type I or II, or C1q withinnormal range.

• Attack rate: Participants must experience at least 1 investigator-confirmed HAE attackper 4 weeks during the run-in period to enter the lanadelumab treatment period.
• The participant (or the participants parent/legal authorized representative, ifapplicable) has provided written informed consent approved by the Institutional ReviewBoard/Independent Ethics Committee (IRB/IEC).
• If the participant is an adult, be informed of the nature of the study and providewritten informed consent before any study-specific procedures are performed or if theparticipant is a minor (ie, below the age of majority), have a parent/legallyauthorized representative who is informed of the nature of the study provide writteninformed consent (ie, permission) for the minor to participate in the study before anystudy-specific procedures are performed. Assent will be obtained from minorparticipants.
• Males, or non pregnant, non lactating females who are fertile and sexually active andwho agree to be abstinent or agree to comply with the applicable contraceptiverequirements of this protocol for the duration of the study, or females of non childbearing potential, defined as surgically sterile (status post hysterectomy, bilateraloophorectomy, or bilateral tubal ligation) or postmenopausal for at least 12 months.
• Agree to adhere to the protocol-defined schedule of assessments and procedures.

Exclusion Criteria:

• Concomitant diagnosis of another form of chronic, recurrent angioedema, such asacquired angioedema (AAE), HAE with normal C1-INH (also known as HAE Type 3),idiopathic angioedema, or recurrent angioedema associated with urticaria.
• Participation in a prior lanadelumab study.
• Dosing with investigational drug or exposure to an investigational device within 4weeks prior to entering to screening.
• Exposure to angiotensin-converting enzyme (ACE) inhibitors or any estrogen-containingmedications with systematic absorption (such as oral contraceptives or hormonalreplacement therapy) within 4 weeks prior to screening.
• Exposure to androgens (eg, danazol, methyltestosterone, testosterone) within 2 weeksprior to entering the run-in period.
• Use of long-term prophylactic therapy for HAE (C1-INH, attenuated androgens, oranti-fibrinolytics) within 2 weeks prior to entering the run in period.
• Use of short-term prophylaxis for HAE 7 days prior to entering the run-in period.Short-term prophylaxis is defined as C1-INH, attenuated androgens, oranti-fibrinolytics used to avoid angioedema complications from medically indicatedprocedures.
• Any of the following liver function abnormalities: alanine aminotransferase (ALT) >3xupper limit of normal, or aspartate aminotransferase (AST) >3x upper limit of normalor bilirubin >2x upper limit of normal (unless the bilirubin is a result of Gilbert'ssyndrome).
• Pregnancy or breast feeding.
• Participant has any condition that in the opinion of the investigator or sponsor, maycompromise their safety or compliance, preclude successful conduct of the study, orinterfere with interpretation of the results (eg, history of substance abuse, ordependence, significant preexisting illnesses or major comorbidity the investigatorconsiders may confound the interpretation of the study results).
• Participant has a known hypersensitivity to the IP or its components.