A Study to Test the Long-term Treatment of Bimekizumab in Study Participants With Moderate to Severe Hidradenitis Suppurativa

The purpose of the study is to evaluate the safety of long-term therapy of bimekizumab in study participants with moderate to severe hidradenitis suppurativa (HS)

Inclusion Criteria: * Study participant has completed the Maintenance Treatment Period through Week 48 in HS0003 (NCT04242446) or HS0004 (NCT04242498), was eligible to receive bimekizumab at the time of completing the feeder study, and did not meet any withdrawal criteria of the feeder study * Study participant is considered reliable and capable of adhering to the protocol (eg, able to understand and complete questionnaires), visit schedule, and medication intake according to the judgement of the Investigator * A female study participant is eligible to participate if she is not pregnant, not breastfeeding, and at least one of the following conditions applies: 1. Not a woman of childbearing potential (WOCBP) OR 2. A WOCBP who agrees to follow the contraceptive guidance during the open-label extension period and for at least 20 weeks after the final dose of investigational medicinal product (IMP) Exclusion Criteria: * Female study participant who is breastfeeding, pregnant, or plans to become pregnant during the study or within 20 weeks following the final dose of investigational medicinal product (IMP) * Study participant has any medical or psychiatric condition that, in the opinion of the Investigator, could jeopardize or would compromise the participant's ability to participate in this study as determined by the Investigator based on protocol required assessments Note: For any study participant with an ongoing serious adverse event (SAE) from HS0003 (NCT04242446) or HS0004 (NCT04242498), or any current sign or symptom that may indicate a medically significant active infection (except for the common cold) or has had an infection requiring systemic antibiotics within 2 weeks of study entry or a history of serious infections in HS0003 or HS0004, the Medical Monitor must be consulted prior to the study participant's entry into HS0005, although the decision on whether to enroll the participant remains with the Investigator. * Study participant has a positive or indeterminate interferon-gamma release assay (IGRA) in a feeder study, unless appropriately evaluated and treated * Study participant has ongoing or planned use of prohibited hidradenitis suppurativa (HS) or non-HS treatment * Study participant plans to participate in another study of a medicinal product or device under investigation during this study