Semaglutide and Follow-On Peptide Therapeutics: Balancing Innovation, Regulation, and Clinical Outcomes.

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have emerged as an important therapeutic class for the management of type 2 diabetes mellitus (T2DM) and obesity owing to their ability to improve glycemic control, promote weight loss, reduce cardiometabolic parameters, and have the added advantage of a low risk of hypoglycemia due to glucose-independent insulin secretion. Semaglutide, a long-acting GLP-1 RA developed using a semi-recombinant process, has demonstrated significant benefits across metabolic and cardiovascular outcomes. Amid the increasing need for affordable therapies, there has been a rising interest in developing synthetic peptide versions of glucagon-like peptide-1 (GLP-1)-based drugs originally produced using recombinant deoxyribonucleic acid (rDNA) technology. However, the transition from recombinant production to chemical peptide synthesis raises important considerations about regulatory pathways, manufacturing processes, and potential clinical implications. Regulatory approaches for synthetic peptides vary across regions. The European Union and the United States follow distinct frameworks, with India adopting a risk-based regulatory approach that may require extensive quality, safety, and clinical data. Manufacturing processes can influence impurity profiles, stability, and immunogenicity, potentially affecting clinical outcomes. Therefore, the approval of follow-on versions of semaglutide requires a rigorous demonstration of both quality and clinical comparability with the originator, consistent with principles applied to biosimilars. Online databases such as PubMed, Scopus, and Google Scholar were used to source relevant research articles. This narrative review aims to discuss the development of semaglutide, examine global and national regulatory perspectives on synthetic and recombinant peptides, and explore the clinical implications of manufacturing variability. It also highlights the expanding therapeutic potential of semaglutide beyond obesity and T2DM.