Antibody-drug conjugates (ADCs) are complex biotherapeutics built from a monoclonal antibody, a cytotoxic payload, and a chemical linker, and their growing clinical use often pushes manufacturers to expand production capacity once a product is approved. Adding a new drug-linker manufacturing site is one of the more common ways this expansion happens, but in the United States it triggers a Supplemental Biologics License Application (sBLA), usually filed as a Prior Approval Supplement. Because the drug-linker has such a direct bearing on product stability, safety, and clinical performance, regulators expect sponsors to show, with solid evidence, that material from the new site is comparable to material from the original one. This review walks through what that evidence typically involves — CMC data, analytical comparability, process validation, stability studies, and inspection readiness — and closes with a case study that illustrates how these requirements play out in practice.

Thota Sathvika, Cheeli Rishitha, Dr. Shailaja Pashikanti, G. Sneha Latha, "Regulatory Considerations in Supplemental BLA Submission for the Addition of Drug-Linker Manufacturing Sites in Antibody-Drug Conjugates" International Journal of Scientific Research and Engineering Development, V9(5): Page(409-414) September - October 2026. ISSN: 2581-7175. www.ijsred.com. Published by Scientific and Academic Research Publishing.