The MHRA is developing non-binding advisory guidance for the licensing requirements for phage products, which will include input from the public. This guidance will be updated in consultation with the phage research and development community as the products and associated methods and technologies mature and in the light of regulatory experience. Genetic modifications influence which regulatory frameworks will apply during phage manufacture. This will be clarified in the MHRA non-binding advisory draft guidance. Genetically engineered (GE) bacteriophages are most likely to be a constituent of licensed products, and, therefore, subject to GMP (all licensed products are currently subject to GMP). It is unlikely that GE phages will be used in named patient or compassionate use cases due to the time needed to engineer and validate them. Phage-derived proteins and other materials sit under the biologicals regulatory framework alongside products such as monoclonal antibodies, cytokines, and recombinant coagulation factors. The requirements of a fit-for-purpose regulatory framework for phage-based medicines are already under consideration by the VMD. This includes the consideration of guidance for the manufacturers and developers of phage-based VMPs. Existing requirements and risk assessments for formulations of VMPs, including genetically modified organisms (GMOs), will be reviewed to ensure they are appropriate for VMPs containing GE phages. However, there is little concern regarding the functionality of the existing framework, given that genetically modified viral vaccines have been successfully and safely authorised in the UK for many years for use in animals.