This study is designed to evaluate the safety after switching to garadacimab from another prophylactic hereditary angioedema (HAE) treatment (marketed kallikrein [KK] inhibitor or plasma-derived C1-esterase inhibitor [pdC1INH]prophylactic) when administered once monthly for approximately 3 months in participants aged greater than or equal to (>=) 12 years with HAE.

Inclusion Criteria:

• • Aged >= 12 years at the time of providing written informed consent / assent.
• • Have a history of response to on-demand HAE treatment for the treatment of acute HAE attacks.
• • Documented laboratory diagnosis in medical records of C1-esterase inhibitor hereditary angioedema (HAE-C1INH) type 1 or type 2:
• ◦ Documented clinical history consistent with HAE (subcutaneous or mucosal, nonpruritic swelling episodes without accompanying urticaria),
• ◦ C1-esterase inhibitor (C1INH) antigen concentration or functional activity less than (<) 50% of normal as documented in the participant's medical record, or
• ◦ C4-antigen concentration below the lower limit of the reference range as documented in the participant's medical record.
• For HAE-nC1INH: Documented clinical history consistent with HAE (subcutaneous or mucosal, nonpruritic swelling episodes without accompanying urticaria); an HAE-associated FXII gene mutation (eg, FXII point mutation Thr328Lys or Thr328Arg, or deletion of 72 base pairs [c.971_1018 + 24del72], or duplication of 18 base pairs [c.892-909dup]), as documented in the participant's medical record, OR an HAE-associated plasminogen gene mutation (PLG) gene mutation (eg, PLG point mutation Lys330Glu), as documented in the participant's medical record; C1INH antigen concentration or functional activity 70 to 120% of the normal level, as documented in the participant's medical record.
• • Use of lanadelumab, berotralstat, or pdC1INH for the prophylactic treatment of HAE and be on a stable (consistent) dose / regimen of such medication for at least 3 months prior to Screening.

Exclusion Criteria:

• • Concomitant diagnosis of another form of angioedema, such as idiopathic or acquired angioedema or recurrent angioedema associated with urticaria.
• • Use of androgens, antifibrinolytics, or investigational products (other than garadacimab) for routine prophylaxis against HAE attacks.
• • Known or suspected hypersensitivity to monoclonal antibody therapy or hypersensitivity to the active substance (garadacimab) or to any of the excipients.

CSL will consider on a case-by-case basis requests to share Individual Patient Data (IPD) with external bona-fide, qualified scientific and medical researchers. For information on the process and requirements for submitting a voluntary data sharing request for IPD, please contact CSL at clinicaltrials@cslbehring.com.

Requests for IPD will generally be considered once review by major regulatory authorities (i.e. FDA, EMA) is complete and the primary publication is available

Proposed research should seek to answer a previously unanswered important medical or scientific question.

Applicable country specific privacy and other laws and regulations will be considered and may prevent sharing of IPD.

If the request is approved and the researcher has executed an appropriate data sharing agreement, IPD that has been appropriately anonymized will be available.