The study aims to compare and assess the dose response of 3 selected doses of maridebart cafraglutide compared with placebo, on inducing and maintaining weight loss from baseline at Week 52 in participants with overweight or obesity without diabetes mellitus (Cohort A) and in participants with overweight or obesity with Type 2 diabetes mellitus (Cohort B).

Inclusion Criteria:

• Age ≥18 years at the time of signing informed consent.
• BMI ≥30 kg/m^2, or ≥27 kg/m^2 and previous diagnosis with at least one of the following comorbidities: hypertension, dyslipidemia, obstructive sleep apnea, cardiovascular disease.
• For participants in cohort B only, HbA1c ≥ 7% and ≤ 10% (53 to 86 mmol/mol) at screening with an established diagnosis of type 2 diabetes mellitus for ≥ 180 days prior to screening and either treated with diet and exercise alone or on stable (at least 90 days prior to screening) treatment with metformin, a sulfonylurea, or a sodium-glucose cotransporter 2 (SGLT2) inhibitor as monotherapy or combination therapy, per approved local label.
• History of at least one unsuccessful dietary effort to lose body weight.

Exclusion Criteria:

• Change in body weight greater than 5 kg within 3 months prior to screening.
• Obesity induced by other endocrinologic disorders.
• History of pancreatitis.
• Family or personal history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2 (MEN-2).
• History of major depressive disorder within the last 2 years.
• Any lifetime history of other major psychiatric disorder or suicide attempt.

De-identified individual patient data for variables necessary to address the specific research question in an approved data sharing request.

Data sharing requests relating to this study will be considered beginning 18 months after the study has ended and either 1) the product and indication (or other new use) have been granted marketing authorization in both the US and Europe or 2) clinical development for the product and/or indication discontinues and the data will not be submitted to regulatory authorities. There is no end date for eligibility to submit a data sharing request for this study.

Qualified researchers may submit a request containing the research objectives, the Amgen product(s) and Amgen study/studies in scope, endpoints/outcomes of interest statistical analysis plan, data requirements, publication plan, and qualifications of the researcher(s). In general, Amgen does not grant external requests for individual patient data for the purpose of re-evaluating safety and efficacy issues already addressed in the product labelling. Requests are reviewed by a committee of internal advisors, and if not approved, may be further arbitrated by a Data Sharing Independent Review Panel. Upon approval, information necessary to address the research question will be provided under the terms of a data sharing agreement. This may include anonymized individual patient data and/or available supporting documents, containing fragments of analysis code where provided in analysis specifications. Further details are available at the URL below.