A Proof-of-concept Study to Evaluate the Efficacy and Safety of Rozanolixizumab to Treat Adult Study Participants With Severe Fibromyalgia Syndrome

Inclusion Criteria

• Study participant must be ≥18 years and ≤70 years of age at the time of signing the informed consent form (ICF)
• Study participant with a diagnosis of fibromyalgia as defined by the 2016 Revisions to the 2010/2011 fibromyalgia diagnostic criteria (American College of Rheumatology Preliminary

Diagnostic Criteria) plus the following characteristics during the Screening Period:

• Brief Pain Inventory-short form (BPI-SF) interference score ≥6.
• Study participant has been diagnosed with fibromyalgia syndrome (FMS) for at least 6 months.
• Study participant has been having FMS symptomatology for at least 2 years before enrollment - Capable of giving signed informed consent as described in the Protocol which includes compliance with the requirements and restrictions listed in the ICF and in the Study Protocol

Exclusion Criteria

• Study participant has been diagnosed with fibromyalgia syndrome (FMS) for >15 years
• Study participant has any systemic autoimmune inflammatory disease
• Study participant has any medical or psychiatric or separate chronic pain condition that, in the opinion of the investigator, could jeopardize or would compromise the study participant's ability to participate in this study or the ability to assess FMS-related pain
• Study participant has severe renal impairment, defined as estimated glomerular filtration rate <30 mL/min/1.73 m^2, (calculated using Modification of Diet in Renal Disease [MDRD] study equation), at Screening visit
• Study participant has a clinically important active infection (including unresolved or not adequately treated infection) as assessed by the investigator
• Study participant has chronic inflammatory demyelinating polyneuropathy
• Study participant has a current or medical history of primary immunodeficiency
• Study participant is pregnant or lactating
• Study participant
• Has suicide attempt in the past 2 years (including an active attempt, interrupted attempt, or aborted attempt),
• OR had suicidal ideation with at least some intent to act in the past 6 months as indicated by a positive response (Yes) to either Question 4 or Question 5 of the Columbia Suicide Severity Rating Scale (C-SSRS) at Screening or Baseline (Visit 3);
• OR is otherwise judged clinically to be at a serious suicidal risk based on the investigator's judgment