This is a Phase 2b, global, multicenter, sequential, randomized, double-blind, placebo-controlled, parallel group, dose-ranging study in participants with moderate to severe hidradenitis suppurativa.

The purpose of the main study is to assess the efficacy and safety of brivekimig in a dose-ranging study of participants with moderate to severe HS.

Study details include:

The study duration (per participant) will be up to approximately 60 weeks for participants not transitioning into the long-term extension (LTE) study and will be up to approximately 52 weeks for participants transitioning into the LTE study.

The randomized treatment duration will be up to approximately 48 weeks.

Inclusion Criteria:

• Participants with a diagnosis of moderate to severe hidradenitis suppurativa (HS) for at least 6 months prior to Baseline
• Participants must have HS lesions present in at least 2 distinct anatomic areas (eg, left and right axilla; or left axilla and left inguinocrural fold), one of which must be Hurley Stage II or Hurley Stage III.
• Participant must have had an inadequate response to a trial of an oral antibiotic for treatment of HS, exhibited recurrence after discontinuation of antibiotics, demonstrated intolerance to antibiotics, or has a contraindication to oral antibiotics for treatment of their HS as assessed by the Investigator through participant interview and review of medical history.
• Participants must be either biologic-naive or biologic-experienced.
• Participant must have a total abscess and inflammatory nodule (AN) count of ≥5 at the Baseline visit.
• Participant must have a draining tunnel count of ≤20 at the Baseline visit.

Exclusion Criteria:

Participants are excluded from the study if any of the following criteria apply:

• Any other active skin disease or condition (eg, bacterial, fungal, or viral infection) that may interfere with assessment of HS
• History of recurrent or recent serious infection
• Known history of significant immunosuppression
• History of solid organ transplant or stem cell transplant
• History of splenectomy
• History of moderate to severe congestive heart failure.
• History of demyelinating disease (including myelitis) or neurologic symptoms suggestive of demyelinating disease
• Participants with a history of malignancy or lymphoproliferative disease other than adequately treated or nonmetastatic squamous cell carcinoma of the skin that was excised and completely cured or nonmetastatic basal cell carcinoma of the skin that was excised and completely cured
• History of any other condition which, in the opinion of the Investigator, would put the participant at risk by participation in the protocol
• Active suicidality and therefore significant suicide risk, as judged by the Investigator
• A history of an Adverse Event (AE) attributed to or related to anti-TNF therapy (examples include, but are not limited, to serum sickness or anaphylaxis) for an HS or non-HS indication that would contraindicate readministration of an anti-TNF class therapy
• Sensitivity to any of the study interventions, or components thereof, or drug or other allergy that, in the opinion of the Investigator, contraindicates participation in the study
• History (within last 2 years prior to Baseline visit) of prescription drug or substance abuse, including alcohol, considered significant by the Investigator

The above information is not intended to contain all considerations relevant to a participant's potential participation in a clinical trial.

Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org