Use and Interchange of Incretin Mimetics in the Treatment of Metabolic Diseases: A Narrative Review.

PURPOSE: Glucagon-like peptide 1 receptor agonists (GLP-1 RAs) and now tirzepatide, a dual GLP-1 RA/glucose-dependent insulinotropic polypeptide agonist, have numerous advantages in the treatment of type 2 diabetes and obesity, yet only 11% of patients with type 2 diabetes are prescribed a GLP-1 RA. This narrative review addresses the complexity and cost issues surrounding incretin mimetics to support clinicians. METHODS: This narrative review summarizes key trials on the differing effects of incretin mimetics on glycosylated hemoglobin and weight, provides a table with rationale for how to interchange among agents, and summarizes the key factors that guide drug selection beyond guidance from the American Diabetes Association. To support proposed dose interchanges, we preferentially selected high-quality, prospective randomized controlled trials with direct comparisons of agents and doses when available. FINDINGS: Tirzepatide produces the greatest reductions in glycosylated hemoglobin and weight, but its impact on cardiovascular events is still under investigation. Subcutaneous semaglutide and liraglutide are approved for weight loss specifically and are effective in the secondary prevention of cardiovascular disease. Although producing less weight loss, only dulaglutide has effectiveness in the primary and secondary prevention of cardiovascular disease. Semaglutide is the only orally available incretin mimetic; however, the oral formulation produces less weight loss versus its subcutaneous alternative and did not have cardioprotection in its outcomes trial. Although effective in controlling type 2 diabetes, exenatide extended release has the least impact on glycosylated hemoglobin and weight among commonly used agents, while not having cardioprotection. However, exenatide extended release may be preferred on some restrictive insurance formularies. IMPLICATIONS: Although trials have not explicitly studied how to interchange among agents, interchanges can be guided by comparisons between agents' impact on glycosylated hemoglobin and weight. Efficient changes among agents can help clinicians optimize patient-centered care, particularly in the face of changing patient needs and preferences, insurance formularies, and drug shortages.