This is a study to confirm the clinical efficacy and safety of sonelokimab compared with placebo in the treatment of adults with active psoriatic arthritis who have had a previous inadequate response or intolerance to anti-tumor necrosis factor (TNF)α therapy.

M1095-PSA-302 is a Phase 3, parallel-group, randomized, double-blind, 4-arm, placebo-controlled, multicenter study with risankizumab as active reference arm to investigate the efficacy and safety of sonelokimab 60 mg and 120 mg versus placebo in adults with active psoriatic arthritis who have had a previous inadequate response or intolerance to anti-tumor necrosis factor (TNF)α therapy.

Inclusion Criteria:

1. Participants must be ≥18 years of age .
2. Participants have a confirmed diagnosis of psoriatic arthritis (PsA) per the 2006 Classification for Psoriatic Arthritis (CASPAR) criteria with symptoms for ≥6 months before the Screening Visit.
3. Participants have active disease (defined by a 68 tender joint count [TJC68] of ≥3 and a 66 swollen joint count [SJC66] of ≥3).
4. Participants have current active plaque psoriasis (PsO) or a dermatologist-confirmed history of plaque PsO.
5. Participants test negative for both rheumatoid factor and anti-cyclic citrullinated peptide at the Screening Visit.
6. Participants must have received 1 or more TNFα inhibitors for PsA or PsO and must have experienced an inadequate response to treatment with at least one TNFα inhibitor(s) given at an approved dose for ≥3 months or have stopped treatment due to safety/tolerability problems after ≥1 administration of a TNFα inhibitor.

Exclusion Criteria:

1. Participants with a known hypersensitivity to sonelokimab or any of its excipients.
2. Participants with a known hypersensitivity, or any contraindication, to risankizumab or any of its excipients or component of the container.
3. Participants who have a diagnosis of chronic inflammatory conditions other than PsO or PsA.
4. Participants with a diagnosis of inflammatory bowel disease.
5. Participants who have experienced a period of ≥3 consecutive weeks of unexplained diarrhea in the 24 weeks before the Baseline Visit.
6. Participants who have an established diagnosis of arthritis mutilans.
7. Previous exposure to sonelokimab.
8. Participants who have ever received biologic immunomodulating agents for PsA or PsO whether investigational or approved, except for those targeting TNFα