Inclusion Criteria:

• * Must be at least 18 years of age and older.
• * Diagnosis or history of clinical features consistent with hidradenitis suppurativa for ≥6 months prior to baseline visit
• * Must have an inflammatory lesion count of ≥5 at the time of screening
• * Must be off oral and intravenous antibiotics or on a stable course of oral antibiotics for ≥28 days prior to the baseline visit. Allowable antibiotics during treatment course are topical clindamycin, topical chlorhexidine gluconate, oral doxycycline, oral minocycline, or oral clindamycin.
• * Must have hidradenitis suppurativa in at least two distinct body locations, i.e. left and right groin
• * Does not have a history of or current Tuberculosis (TB)

Exclusion Criteria:

• * Have had surgical intervention beyond incision and drainage in the last 8 weeks or have open surgical wounds
• * Planning a major elective surgery during the time of the study.
• * Taking other immunomodulatory or biologic treatment for Hidradenitis Suppurativa
• * Previous treatment with anifrolumab for any reason.
• * Are pregnant, lactating, or intend to become pregnant or lactate for up to 16 weeks following the last dose of study drug upon signing the Informed Consent Form (ICF)
• * Severe herpes zoster infection
• * Known history of allergy or reaction to any component of the study drug
• * History of cancer (some cases of basal cell carcinoma and squamous cell carcinoma of the skin as well as cervical carcinoma in situ may be eligible).
• * Primary immunodeficiency, splenectomy, or any underlying condition that predisposes participants to infection, or a positive HIV test.
• * Active Hepatitis
• * Clinical Cytomegalovirus or Epstein-Barr infection that has not completely resolved within 12 weeks prior to signing the informed consent.
• * Opportunistic infection that required hospitalization or intravenous antimicrobial treatment within 3 years of baseline.
• * Clinically significant chronic infection (e.g., osteomyelitis, bronchiectasis) within 8 weeks prior to signing the informed consent.
• * Any history of severe COVID-19 infection (e.g. prolonged hospitalization \[hospitalization for observational purposes is not exclusionary\]) or any prior COVID-19 infection with documented long COVID-19 and/or clinically significant unresolved sequelae. Any mild/asymptomatic infections COVID-19 infection (lab confirmed or suspected based on clinical symptoms) within the last 6 weeks prior to first dosing.
• * Abnormal laboratory tests indicating severe anemia, severely impaired liver function or immunosuppression.
• * History of, or current diagnosis of, catastrophic anti-phospholipid syndrome within 1 year prior to signing the informed consent. (Other degrees of anti-phospholipid syndrome that is adequately controlled by anticoagulants or aspirin for at least 12 weeks may be eligible).
• * History of or evidence of suicidal ideation within the past 6 months or any suicidal behavior within the past 12 months or recurrent behavior in the participant's lifetime.
• Other protocol-specific inclusion/exclusion criteria may apply.