Phage therapies could be our best weapon in the fight against antibiotic resistance

But today we face a new crisis, where these serious but easily treatable diseases may be back with force. 

Antimicrobial resistance is one of the biggest threats to human health. Once-reliable antibiotics are proving ineffective against some strains of bacteria, which have adapted to become drug-resistant. In 2023, the UK saw nearly 70,000 serious infections from antibiotic-resistant bacteria; globally, drug-resistant strains could lead to more than 8 million direct deaths by 2050. There is also a huge economic burden associated with resistant infections. Estimations from The World Bank suggest that antimicrobial resistance could result in US $1 trillion of additional healthcare costs by 2050, and up to US $3.4 trillion GDP losses by 2030.

Antibiotics are no longer the silver bullet they once were, but phage therapies could offer a game-changing solution.

Bacteriophages, the bacteria killers

Bacteriophages — commonly just called phages — are viruses. Phages are the most abundant life form on earth. They are found everywhere in our environment and are even present in our bodies. These viruses are specialised bacteria hunters. They find and attach to receptors on the cell walls of bacteria. They then inject their own genetic material into a targeted bacterium as a ​‘set of instructions’ for the bacterium’s reproduction machinery to use to make more phages. The bacterium sets to work mass-producing new phages, and these eventually burst out of the bacterium, destroying it. 

What is particularly useful about this process is that phages have high specificity — each phage will find and attach to a specific species or even strain of bacteria. This is different from antibiotics, which work more broadly, indiscriminately destroying any bacteria in their immediate environment, often resulting in the mass destruction of both helpful and essential ​‘friendly bacteria’. 

Harnessing the specificity of phages could help us create a multitude of therapies that precisely target a huge range of different, disease-causing bacteria.

We can enhance the power of phages

While phage therapies have been in use for some time, today we have powerful gene editing tools like CRISPR/​Cas9 at our disposal to make phages work even better. Using genetic engineering, we could enhance the seek-and-destroy nature of phages to make them even more precise, or to target specific bacterial strains we know to be drug-resistant. We could also upgrade their weaponry, editing the viral genome to make it more effective at killing the bacteria. 

There’s a further potential benefit: increased specificity combined with a heightened destruction ability could make phages much faster at killing bacteria. Many of us will be familiar with the instructions from our GP to take a course of antibiotics for 7 or 10 days — this is to ensure that the antibiotics have wiped out every last infection-causing bacterium. But the longer a treatment takes to work, the longer the surviving bacteria have to adapt and develop resistance. With fast-acting phage therapies, the bacteria simply wouldn’t have long enough to build resistance. 

Phage therapies, then, could offer us a way to treat infections in a more targeted, efficient way while at the same time reducing the need for antibiotics, in turn reducing the risk of new, drug-resistant strains of bacteria evolving. In short, improving health at the individual and global level. 

However, phage therapies remain underdeveloped due to some persistent challenges. Phages are live microorganisms, so growing them at scale is difficult, especially when this needs to be done to Good Manufacturing Practice (GMP) for producing phage therapies to treat patients. So, too, is maintaining purity and standardisation across large batches. And antibiotics have historically been favoured because of their ability to work across a broad spectrum of bacterial strains. That means one type of antibiotic can be useful against lots of different infections while phages are highly targeted. Yet now that we know there is a downside to this initial benefit, it’s time for phage therapies to get some attention. 

We are beginning to see some of these CRISPR phage technologies in clinical trials, and it’s an exciting time to be involved in the field.

CPI can help drive phage therapy development

At CPI, we see the huge potential phage therapies have, not just for individuals who need treatment, but for humanity’s broader fight against disease. And we are uniquely well placed to support companies and research groups working in this frontier research. 

One of our strengths as an organisation is the breadth of sectors we work across, from healthcare and future food-production systems to AgriTech and sustainable materials. We can cross-pollinate expertise, bringing together knowledge from these different sectors and research disciplines. The engineering biology sector is multidisciplinary; we need to build networks not only of people who have life-sciences skills but also experts in AI, biomanufacturing, bioinformatics and computational biology. 

We are already creating centres of expertise to drive new discoveries and techniques in phage therapies, like our cystic fibrosis translational innovation hubs, led by the University of Liverpool. Here, we are progressing potential new phage therapies that could treat lung infections in people living with cystic fibrosis. 

Another key role we play is working with companies to develop and scale manufacturing processes. Like our work — also with the University of Liverpool — to develop a manufacturing process for phages against Pseudomonas aeruginosa, which can cause life-threatening infections. This involves optimising and scaling the manufacturing process, defining the quality criteria for the product, and developing the analytical methods for assessing that these criteria have been met. 

Of course, expertise is just one part of developing new therapies. We also need infrastructure. From our Medicines Manufacturing Innovation Centre to our National Biologics Manufacturing Centre, our network of sites across the UK houses cutting-edge facilities to help SMEs and researchers turn ideas into reality. 

Phage therapies will be a major tool as we adapt to a world where antibiotics are no longer the reliable treatment of the last century. By continuing to support phage therapy innovation and commercialisation — all while boosting the UK’s pharmaceuticals sector — CPI is helping create innovative treatments for at-risk individuals and respond to a global health crisis.