As radiopharmaceutical therapy (RPT) expands beyond neuroendocrine tumors and prostate cancer, it is important to understand the U.S. Food and Drug Administration (FDA) approval process and to establish a shared vocabulary for effective communication. The 505(b)(2) New Drug Application is a well-established mechanism for FDA approval of nuclear medicine products. It is an application for drugs that are similar to an approved product, supported by published literature and studies conducted on similar drugs, and bridging studies demonstrating the scientific relevance of the data to the product. This streamlined approval pathway can encourage development of more treatment options, facilitating greater patient access and improved resilience to supply chain disruptions. The evolving RPT landscape necessitates new nomenclature. "Radioligand equivalent" refers to an RPT approved through the 505(b)(2) pathway, distinct from a generic RPT approved through an Abbreviated New Drug Application. Establishing shared terminology supports clear multidisciplinary communication and fosters informed treatment selection.
Journal of nuclear medicine : official publication, Society of Nuclear Medicine. 2026 Apr 30 [Epub ahead of print]
Aman Chauhan, Andrew E Hendifar, Ghassan El-Haddad, Heloisa P Soares, Ken Herrmann
School of Medicine, University of California, San Francisco, San Francisco, California; ., Division of Hematology-Oncology, Department of Internal Medicine, Cedars-Sinai Medical Center, Los Angeles, California., Department of Diagnostic Imaging and Interventional Radiology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida., Department of Internal Medicine, Division of Oncology, Huntsman Cancer Institute at University of Utah Health Care, Salt Lake City, Utah., Department of Nuclear Medicine, University of Duisburg-Essen, Essen, Germany; and.