The main purpose of this study is to assess the effectiveness of adding tirzepatide to ixekizumab therapy in standard clinical practice in participants with moderate-to-severe plaque PsO and obesity or overweight with at least 1 weight-related comorbidity.

The study will last up to 12 months.

Inclusion Criteria:

• Have a diagnosis of moderate-to-severe plaque PsO, as defined by a dermatologist or other experienced clinician treated PsO (for example, allergologist, nurse practitioner or physician assistant)
• Have body mass index (BMI) of 30 kilograms per meter squared (kg/m²) or greater (obesity) or 27 kg/m² to <30 kg/m² (overweight) in the presence of at least 1 weight-related comorbid condition (hypertension, dyslipidemia, type 2 diabetes mellitus, obstructive sleep apnea, or cardiovascular diseases).
• Must have initiated treatment with ixekizumab for approximately 3 months (± 1 month) prior to decision to add tirzepatide.
• Must be able to initiate tirzepatide (Day 0) within 30 days of treatment decision (baseline/screening).

Exclusion Criteria:

• Have currently received ixekizumab for more than 4 months or less than 2 months.
• Have had any exposure to tirzepatide or other glucagon-like peptide-1 receptor agonist (GLP-1 RAs), for example, dulaglutide, liraglutide, or semaglutide.
• Are currently enrolled in any other clinical study.

Other exclusions

• Have a known hypersensitivity to tirzepatide or to any of its component.
• Have a personal or family history of medullary thyroid cancer.
• Have multiple endocrine neoplasia type 2.
• Have type I diabetes mellitus.
• Have a history of chronic or acute pancreatitis at any time before screening (Visit 1).
• Have a history of proliferative diabetic retinopathy, diabetic maculopathy, or nonproliferative diabetic retinopathy that requires acute treatment.
• Have a history of ketoacidosis or hyperosmolar state/coma.
• Have a history of severe hypoglycemia and hypoglycemia unawareness within the 6 months before screening.
• Have a history of severe gastrointestinal complications, including gastroparesis, gastroesophageal reflux disease, dyspepsia, chronic nausea/constipation/vomiting.

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.