A Study to Evaluate ALN-4324 on Insulin Sensitivity in Adults With Type 2 Diabetes Mellitus

Inclusion Criteria: * Is an adult patient with a confirmed diagnosis of T2DM * Has a body mass index (BMI) of ≥23 kg/m\^2 to ≤39.9 kg/m\^2 * Has a hemoglobin A1c (HbA1c) ≥6.5% to \<10.5% * Is on a stable dose of metformin, sodium-glucose cotransporter 2 inhibitor (SGLT2i), or dipeptidyl peptidase-4 inhibitor (DPP4i) Exclusion Criteria: * Has any clinically significant concomitant disease, medical condition, or abnormal laboratory finding that could compromise participant safety or confound interpretation of study results * Receiving therapies known to interfere with glucose or insulin metabolism other than current treatment for T2DM or birth control methods Note: other protocol defined inclusion/exclusion criteria apply