Quis Custodiet? Are Regulations Slowing Phage Therapy?

Rising levels of antibiotic-resistant bacteria have led to increasing interest in the use of phage therapy as an alternative treatment. While phage therapy is conceptually simple, and numerous semi-anecdotal data suggest that it could be effective if properly managed, there have been only a few randomized, double-blind clinical trials of phage therapy so far. These trials unequivocally showed that phage therapy is safe, but there is still a paucity of data on its efficacy for managing various bacterial infections. One common response to this situation is that there is a mismatch between the regulations that govern the testing of new drugs, that is, chemical agents, and biological agents like bacteriophages. Another response has been to sidestep clinical trial testing and to use phages to treat infected patients on an individual basis, sometimes called the magistral phage approach. In this paper, we argue that regulations are not the true barrier to approval of phage therapy as drugs but rather it is the lack of efficacy data. There is no one reason behind the failures of recent clinical trials. Instead, these demonstrate the complexity of implementing a therapy where both the treatment and disease are living entities interacting within another living entity, the patient. Phage banks can have an impact by monitoring these complexities during phage therapy. Importantly, phage therapy clinical trials are continuing under existing regulatory frameworks and with products manufactured under GMP (Good Manufacturing Practices).