A consensus-based guideline for personalized bacteriophage therapy.

Bacteriophages (phages) - viruses that selectively infect bacteria - are a promising option for personalized therapy of difficult-to-treat bacterial infections. Clinical implementation in many countries worldwide, however, faces multiple hurdles, including a lack of consensus on general principles for phage therapy, infrastructural requirements, procedures for quality-assured phage selection and preparation, clinical administration, monitoring and documentation. Existing guidance provides limited practical direction across the entire translational pathway and lacks inspection-ready specifications to support both pharmacies and clinical sites. These gaps impede safe and transparent clinical use and effective regulatory oversight. Likewise, there are no established processes to identify research questions that will be key to advancing clinical phage research in the future. To address these needs, this consensus-based guideline was developed within the methodological framework of the Association of the Scientific Medical Societies in Germany under the leadership of the German Society for Infectious Diseases. It was created through a collaborative effort involving 20 professional societies, patient advocacy groups and regulatory authorities and 18 international experts. The guideline provides over 60 recommendations on core principles, infrastructure, preparation and quality control, administration and future research. Recommendations are supported by international societies, organizations and stakeholders. By providing clear and practice-oriented recommendations, this consensus statement paves the way for the safe and standardized use of personalized phage therapy.