Published August 2015
Design and Analysis of Shedding Studies for Virus or Bacteria-Based Gene Therapy and Oncolytic Products The Center for Biologics Evaluation and Research (CBER)/Office of Cellular, Tissue, and Gene Therapies (OCTGT) is issuing this guidance to provide you, sponsors of virus or bacteria-based gene therapy products (VBGT products)1 and oncolytic viruses or bacteria (oncolytic products)2 with recommendations on how to conduct shedding studies during preclinical and clinical development. For purposes of this guidance, the term “shedding” means release of VBGT or oncolytic products from the patient through one or all of the following ways: excreta (feces); secreta (urine, saliva, nasopharyngeal fluids etc.); or through the skin (pustules, sores, wounds). Shedding is distinct from biodistribution because the latter describes how a product is spread within the patient’s body from the site of administration while the former describes how it is excreted or released from the patient’s body. Shedding raises the possibility of transmission of VBGT or oncolytic products3 from treated to untreated individuals (e.g., close contacts and health care professionals). This guidance represents FDA’s current thinking on how and when shedding data should be collected for VBGT and oncolytic products during preclinical and clinical development and how shedding data can be used to assess the potential for transmission to untreated individuals. This guidance finalizes the draft guidance of the same title dated July 2014.