The main purpose of the SYNERGY-OUTCOMES study is to find out whether retatrutide and tirzepatide can prevent major adverse liver outcomes (MALO) in people with high-risk metabolic dysfunction-associated steatotic liver disease (MASLD). The study will enroll adults who have MASLD based on non-invasive tests (NITs), which indicate they are more likely to develop MALO. Participants will be randomly assigned within a Master Protocol to receive either retatrutide (N1T-MC-RT01), tirzepatide (N1T-MC-TZ01) or placebo. The trial plans to enroll about 4,500 adults and will run for approximately 224 weeks. Participants may have up to approximately 25 to 30 clinic visits throughout the study to monitor their health, complete study procedures, and assess liver function and disease progression.

Once the study is complete, eligible participants may participate in an optional 2-year extension study, in which all participants will receive either retatrutide or tirzepatide, even if they received placebo in the main study.

Inclusion Criteria:

• Have liver fat content ≥8%
• Have ELF score of ≥9 and ≤10.8 at screening
• Have VCTE LSM ≥10 kilopascal (kPa) and <20 kPa at screening

Exclusion Criteria:

• Have any other type of liver disease other than MASLD
• Have a body mass index (BMI) <25 kilogram per square meter (kg/m2)
• Prior decompensated liver disease (history of esophageal/gastric varices, ascites, hepatic encephalopathy)
• Have lost more than 11 pounds within the 3 months prior to screening
• Have a hemoglobin A1c (HbA1c) greater than 10%
• Have type 1 diabetes

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 or 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.