This is a study to demonstrate the long-term safety, tolerability and clinical efficacy of sonelokimab in the treatment of patients with psoriatic arthritis who completed a parental study (M1095-PSA-301 or M1095-PSA-302)

M1095-PSA-303 is a Phase 3, multicenter, open-label extension study to investigate the long-term safety, tolerability and clinical efficacy of sonelokimab 60 mg subcutaneously every 4 weeks in patients with psoriatic arthritis who completed a parental study (M1095-PSA-301 or M1095-PSA-302).

Inclusion Criteria:

1. Participants who, in the opinion of the investigator, are expected to benefit from participation in this OLE study.
2. Participants who have received the second to last and/or last dose, as planned in the parental study, and have completed the end-of-treatment visit of the parental study.
3. Participants must have received their last dose of study treatment in the parental study no more than 8 weeks (but ideally 4 weeks) before the first dose in this OLE study.
4. Female participants are eligible to participate if they are not pregnant or breastfeeding and must be of nonchildbearing potential or must agree to use highly effective methods of contraception during the study and for at least 8 weeks after the last dose of study treatment. Female participant of childbearing potential must refrain from donating oocytes during the study and for at least 8 weeks after the last dose of study treatment.
5. Male participants must be willing to use a condom when sexually active with a partner of childbearing potential during the study and for at least 8 weeks after the last dose of study treatment, unless surgically sterile. Male participants must also agree to refrain from donating sperm during the study and for at least 8 weeks after the last dose of study treatment.

Exclusion Criteria:

1. Participants who met any of the discontinuation criteria of the parental study at the time of enrollment in this OLE study.
2. Participants who have ongoing or planned use of one or more of the prohibited PsA or non-PsA treatments specified in this protocol.
3. Participants who plan to participate in another interventional study for a drug or device during this study.
4. Participants who were unblinded during the parental study.
5. Participant noncompliance to the parental study