Breaking down barriers to improve phage therapy delivery.

There is growing interest in the development of bacteriophages as therapies for antimicrobial-resistant infections, but effective delivery of phages remains a barrier. This review examines the opportunities and challenges involved in the development of phages as drugs, focusing on phage delivery. We first review current practices and success rates for clinical phage therapy and recent advances in phage selection and design. Next, we frame ongoing delivery challenges in the context of what is known about phage biology and phage pharmacokinetics. We then explore barriers to effective phage delivery alongside dosing and administration strategies used to overcome them, followed by an examination of recent innovations in phage formulations and biomaterials technologies. Finally, we highlight outstanding questions and challenges in the field. We conclude that optimizing delivery is a key determinant of the success of phage therapy and that the integration of microbiology, materials science, and pharmacology will enable more consistent success.