The main purpose of this study is to demonstrate that when participants with psoriatic arthritis and obesity or overweight in the presence of at least 1 weight-related comorbid condition receive ixekizumab and tirzepatide concomitantly administered, participants see improvement in their psoriatic arthritis and achieve weight reduction compared to when receiving ixekizumab.

Participation in this study includes up to 12 visits and could last up to 61 weeks including screening, open label treatment period, and post-treatment follow-up period.

Inclusion Criteria:

• Have signs and/or symptoms or documented diagnosis of Psoriatic Arthritis (PsA) for at least 6 months and currently fulfilling the classification of Psoriatic Arthritis (CASPAR) criteria.
• Have active PsA, defined as the presence of at least 3 of 68 tender joints and at least 3 of 66 swollen joints.
• Have obesity, body mass index of ≥30 kilograms per meter squared (BMI ≥30 kg/m²) or overweight (BMI ≥27 to <30 kg/m²) in the presence of at least 1 of these weight-related comorbid conditions (hypertension, dyslipidemia, obstructive sleep apnea, cardiovascular disease, or T2DM).

Exclusion Criteria:

Medical Conditions

• Have Type 1 Diabetes Mellitus (T1DM).

• Have insulin-treated Type 2 Diabetes Mellitus (T2DM).

• Have a prior or planned surgical treatment for obesity.

• Have a family or personal history of medullary thyroid carcinoma (MTC) or multiple endocrine neoplasia (MEN) syndrome type 2.

• Have active, or a history of inflammatory bowel disease (Crohn's or ulcerative colitis).

• Have a diagnosis or history of malignant disease within the 5 years prior to randomization, with the following exceptions:

  • basal cell or squamous epithelial carcinomas of the skin that have been resected, with no evidence of metastatic disease for 3 years.
  • cervical carcinoma in situ, with no evidence of recurrence within the 5 years prior to randomization.

• Have a serious disorder or illness other than PsA.

• Have a history of chronic or acute pancreatitis.

• Have any prior use of ixekizumab or tirzepatide.

• Diagnosis of other inflammatory arthritis, such as Rheumatoid Arthritis (RA), ankylosing spondylitis, reactive arthritis, gout, or enteropathic arthritis.

• Have a previous failure or intolerance to an interleukin 17 inhibitor (IL-17i) or glucagon-like peptide 1 (GLP-1) receptor agonists.

Anonymized individual patient level data will be provided in a secure access environment upon approval of a research proposal and a signed data sharing agreement.

Data are available 6 months after the primary publication and approval of the indication studied in the US and EU, whichever is later. Data will be indefinitely available for requesting.

A research proposal must be approved by an independent review panel and researchers must sign a data sharing agreement.