France’s Phage Therapy Moment: How Research, Hospitals and Industry Are Converging to Build a European Pioneer

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France is entering a decisive phase in the development of bacteriophage therapy. For years, the country possessed many of the components required to advance phages from experimental antimicrobials toward modern biological medicines: internationally recognized research teams, clinicians experienced in compassionate treatment, hospital microbiology laboratories, national reference networks, pharmaceutical production capabilities, a medicines regulator willing to construct controlled access pathways and a growing biotechnology sector. What was missing was not scientific interest, but coordination. In 2026, the launch of Inserm’s Phage Therapy Booster Programme signals an attempt to assemble these dispersed capabilities into a coherent national strategy. Its importance lies not in promoting one phage, one bacterial pathogen or one clinical indication, but in addressing the entire development chain, from host-range prediction and synthetic biology to pharmaceutical production, preclinical pharmacology, regulation, economic accessibility and social acceptance.

This strategy emerges at a moment when phage therapy is moving beyond the question of whether bacteriophages can kill antibiotic-resistant bacteria. That point has long been established experimentally, and compassionate treatments have shown that phages can sometimes contribute to the control of otherwise intractable infections. The more difficult question is whether these living antibacterial agents can be transformed into reliable, reproducible and accessible medicines. Unlike conventional antibiotics, bacteriophages replicate only in susceptible bacterial hosts, often display narrow and strain-dependent activity, evolve alongside their targets and interact dynamically with bacterial physiology, antibiotics, biofilms and the immune system. Their therapeutic use therefore requires a development model that can accommodate biological variability without abandoning pharmaceutical standards.

Inserm’s programme directly addresses this tension. It is jointly led by the thematic institutes Technologies for Health and Immunology, Inflammation, Infectiology and Microbiology, reflecting the recognition that phage therapy cannot be developed by microbiology alone. The initiative seeks to mobilize microbiologists, infectious-disease specialists, bioengineers, pharmacologists, mathematical modellers, synthetic biologists, bioprocess experts, immunologists, clinicians, health economists and social scientists. Inserm intends to constitute a national consortium of approximately ten to twelve participants or teams, organized around interconnected work packages and selected through an international scientific evaluation process. The final consortium is expected to co-construct a three-year programme before its planned launch in January 2027. Inserm describes its booster-programme model as providing interdisciplinary consortia with €1.5 million over three years, while encouraging them to prepare larger national and European projects.

The first scientific ambition is to improve the ability to match a therapeutic phage with the bacterial strain responsible for an individual infection. A phage active against one isolate of Pseudomonas aeruginosa, Staphylococcus aureus or Escherichia coli may be ineffective against another member of the same species. Susceptibility depends on bacterial receptors, capsules, lipopolysaccharides, pili and membrane proteins, but also on intracellular defence systems, prophage-mediated exclusion, metabolic state and the spatial organization of the bacterial population. A conventional spot test provides useful information, but it does not capture every determinant of productive infection or predict how the same interaction will behave in a biofilm, tissue or immunologically active host.

Inserm therefore proposes high-throughput platforms integrating phenotypic measurements, genomic analysis, automation, miniaturization, microfluidics and machine learning. The objective is to generate structured phage–bacterium interaction datasets that can support increasingly predictive selection rather than relying only on slow trial-and-error screening. Panels of clinically representative isolates could be tested against large phage collections while measuring bacterial suppression, viral amplification, resistance and temporal infection dynamics. Algorithms could then connect these results with receptor architecture, bacterial defence systems, phage genome features and environmental conditions. Such systems would not eliminate the experimental phagogram, but they could make it faster, more quantitative and more informative.

The programme also recognizes that a phage bank is only useful when its contents are deeply characterized and biologically complementary. Accumulating hundreds of viruses does not automatically provide broad clinical coverage if many target the same receptor, fail against the same defence system or cannot be manufactured reproducibly. Rational phage banking requires genomic safety assessment, receptor diversity, host-range mapping, resistance analysis, stability data and production feasibility. Rational cocktail design must similarly move beyond assembling several active phages and instead consider whether their mechanisms remain complementary under the conditions found in the patient.

When natural diversity is insufficient, Inserm intends to support synthetic biology and phage engineering. The programme proposes an integrated Design–Build–Test–Learn framework for modifying host-range determinants such as receptor-binding proteins, tail fibres and tail spikes, introducing anti-defence functions or delivering genetic payloads designed to reduce virulence or restore antibiotic susceptibility. Artificial intelligence and structural biology could assist the design of new binding modules, while high-throughput construction and testing could accelerate the evaluation of engineered variants. These developments could eventually produce broader or programmable therapeutic phages, but they also create additional safety and regulatory questions. Genomic stability, manufacturing consistency, environmental dissemination and control of genetic modifications must therefore be considered from the beginning rather than added after a candidate has already been selected.

Bioproduction forms the other half of this first axis. A phage may possess excellent antibacterial properties and still fail as a medicinal candidate because it cannot be amplified at high titre, purified consistently, stabilized during storage or produced without unacceptable levels of endotoxins and bacterial contaminants. Manufacturing is particularly difficult when therapeutic strategies require several phages or rapid adaptation to a patient’s isolate. Every additional component increases analytical work, quality-control requirements and production costs.

Inserm proposes to investigate both upstream and downstream solutions. Upstream work may include safer non-pathogenic production strains, removal of inducible prophages, receptor engineering and automated evolution of bacterial hosts with improved productivity. Downstream development must optimize purification, concentration, formulation, stability and release testing while preserving infectivity. Cell-free phage production is also considered as a longer-term possibility that could reduce contamination risks and support distributed manufacturing. The central objective is to make therapeutic-grade phages available more rapidly and at a cost compatible with a public healthcare system rather than treating every preparation as an exceptional artisanal product.

The second axis of the Inserm programme addresses another major source of translational failure: the distance between standard laboratory assays and the biological environment encountered in patients. Phages that rapidly suppress planktonic bacteria in rich culture media may behave very differently against slow-growing organisms embedded in biofilms, protected within mucus, associated with implants or located inside poorly vascularized tissues. Their activity can also be modified by antibiotics, bacterial density, immune cells, antibodies, local pH, inflammatory molecules and the route of administration.

Inserm therefore calls for human-relevant experimental systems based on cells, tissues, organoids, ex vivo models, microfluidic devices and advanced imaging. Such platforms could reproduce selected features of pulmonary, intestinal, cutaneous or osteoarticular infections while allowing investigators to vary phage composition, antibiotic exposure, dose and timing. These systems would complement rather than replace animal models, but they could explore a much larger experimental space and provide more mechanistic information about tissue penetration, biofilm disruption, bacterial resistance and host responses.

The programme also places phage pharmacology at the centre of development. Bacteriophages can amplify in the presence of susceptible bacteria, but they are still biological particles subject to distribution, retention, neutralization and clearance. They may be captured by the reticuloendothelial system, filtered through the kidneys, internalized by immune cells or neutralized by antibodies after repeated exposure. Their effective concentration at the infection site therefore depends on more than the administered dose. Inserm seeks to develop multiscale pharmacokinetic and pharmacodynamic models capable of integrating bacterial growth, phage replication, antibiotic interactions, immune responses, biodistribution and stochastic infection outcomes. This could help transform dose selection from an empirical decision into a predictive therapeutic strategy.

The third axis is equally important because technical success alone will not guarantee patient access. Inserm intends to study the regulatory status of natural and modified phages, the evidence required before human administration, the perception of phage therapy among clinicians and patients, the economic models supporting personalized biological medicines and the environmental consequences of wider phage use. This is unusual in antimicrobial development, where questions of acceptability, cost and integration into healthcare are often considered only after a product has already been created.

The programme explicitly distinguishes natural phages from genetically modified candidates. The latter may require new regulatory interpretations because deliberate changes to host range, payloads or anti-defence functions can alter biological and environmental behaviour. Inserm also proposes qualitative research involving patients, clinicians, nurses, researchers, professional societies and other stakeholders. The objective is not simply to persuade the public that phages are safe, but to understand concerns early enough for them to influence product design, trial protocols and communication.

This national programme is supported by a substantial research base. Laurent Debarbieux’s team at Institut Pasteur studies the biology of phage–bacterium–host interactions, pulmonary phage therapy, pharmacokinetics, safety and the molecular characterization of therapeutic phages. The group also develops the Viral Host Range database, designed to organize and analyse experimental information on which viruses infect which bacterial hosts. These activities illustrate the type of mechanistic, computational and translational expertise that the Inserm programme intends to connect at national scale.

The scientific working group that prepared the Inserm initiative further demonstrates the geographical and disciplinary breadth of the French ecosystem. It brought together expertise from Paris, Lyon, Bordeaux, Marseille, Nantes, Tours, Poitiers, Limoges and Montpellier, encompassing phage biology, microbiology, pharmacology, respiratory delivery, antimicrobial resistance, bioengineering, microbiome research, public health and social sciences. These contributors are not automatically the future programme consortium, which will be selected separately, but their involvement shows that France already possesses many of the required competencies. The strategic challenge is to make them function as one translational system rather than as isolated centres of excellence.

The hospital pillar is particularly advanced in Lyon. The Hospices Civils de Lyon have built a continuum that connects phage isolation and microbiological characterization at the Institut des Agents Infectieux with pharmaceutical purification, formulation and quality control at the FRIPHARM platform. On 28 May 2026, the French medicines agency authorized the HCL to manufacture crude phage production intermediates and purified phage active substances intended for human use. The HCL describe this as the first authorization of its kind granted to a French public healthcare institution. The authorization allows production under pharmaceutical manufacturing requirements and the preparation of batches containing several hundred vials.

This development is scientifically and politically important. It demonstrates that hospital-based public production can potentially convert phages isolated from environmental reservoirs into controlled pharmaceutical preparations without transferring the entire process to a multinational manufacturer. FRIPHARM performs purification, formulation, analytical quality control and batch release, after which hospital preparations can be produced for human administration. The model is not yet equivalent to a national marketing authorization or mass commercial production, but it provides France with a public platform capable of linking research, urgent clinical need and regulated manufacturing.

The Lyon infrastructure emerged through several years of clinical and research activity. PHAGEinLYON developed a collection and translational programme focused especially on severe osteoarticular infections. PHAG-ONE subsequently received €2.85 million within the French priority research programme on antimicrobial resistance to establish an integrated academic chain for isolating, producing, purifying, formulating and controlling therapeutic phages active against Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli. The project is coordinated by the HCL with Université Claude Bernard Lyon 1 and the Centre International de Recherche en Infectiologie, while involving research institutions in several other French regions.

The RHU THERAPhage programme extends this trajectory by combining expansion of public phage production, automated phagogram development and innovative medical devices capable of releasing phages at infected sites. Its consortium includes hospital, university and industrial partners and seeks to develop additional phages, including candidates targeting Pseudomonas aeruginosa. This illustrates how French hospital research is moving beyond compassionate supply toward integrated programmes that include diagnostics, formulation, delivery systems and prospective clinical evaluation.

The national regulator has also begun constructing a controlled access pathway. The ANSM authorizes compassionate access to the anti-Staphylococcus aureus phages PP1493 and PP1815 for severe documented bone and osteoarticular infections in patients facing therapeutic failure. Their use is restricted to hospitals, requires collegial validation by a French reference centre for complex osteoarticular infections and depends on a phagogram confirming activity against the patient’s bacterial isolate. The two phages must be administered together to reduce the risk of resistance, and real-world safety and use data are collected. This framework demonstrates both the potential and the complexity of personalized phage therapy: microbiological matching, clinical selection, regulated supply and patient monitoring must all occur in coordination.

Research and hospitals, however, cannot create a durable therapeutic sector alone. The third pillar is industrial. France’s emerging phage biotechnology ecosystem remains heterogeneous, and not every company develops conventional human phage medicines. Some focus on programmable microbiome editing, veterinary treatment, environmental applications, phage-derived proteins or bioinformatics. This diversity should not be interpreted as a weakness. It provides complementary technologies that may ultimately support human therapeutics, including genome engineering, host-range prediction, production, quality control, artificial intelligence, diagnostics and One Health deployment.

Phage Atlas currently identifies six French companies operating directly with bacteriophages or phage-derived technologies: Eligo Bioscience in Paris, GREENPHAGE in Clapiers, Phagenix in Lyon, Phagos in Suresnes, Rime Bioinformatics in Palaiseau and Vetophage in Saint-Priest. The map is a useful starting point for understanding the sector, but the companies differ substantially in their maturity, applications and therapeutic objectives.

Eligo Bioscience represents the most advanced French example of transforming phage-derived delivery into programmable microbiome medicine. Rather than depending exclusively on complete replicating lytic phages, Eligo uses engineered phage-derived particles to deliver synthetic DNA into selected bacterial populations. Its platform includes sequence-specific antimicrobials based on CRISPR nucleases, in vivo bacterial genome editing and the addition of therapeutic functions to defined members of the microbiome. In a 2024 study, the company reported highly efficient editing of intestinal Escherichia coli in mice using a phage-derived capsid carrying a base-editing system. The approach illustrates how French phage biotechnology is expanding from bacterial killing toward precise manipulation of disease-associated microbial genes.

Eligo’s position is important for the Inserm strategy because its work intersects with several programme priorities: synthetic biology, engineered payloads, phage particle production, microbiome targeting, genomic safety and regulatory development of modified biological agents. It also demonstrates the value of connections between academic research and biotechnology. The company was founded around expertise involving Institut Pasteur and international synthetic-biology researchers, showing how discoveries in bacterial genetics can generate a French industrial platform with global ambitions.

Phagenix represents a more direct human phage-therapy model. Based in Lyon, the company describes itself as a specialty pharmaceutical company dedicated to developing bacteriophage-based antibacterial treatments for severe resistant infections in humans. Its geographical proximity to the HCL, CIRI, Université Claude Bernard Lyon 1 and the wider Lyon phage ecosystem creates the possibility of interactions between clinical expertise, public manufacturing, microbiology and private drug development. The public information currently available provides less detail about its candidate pipeline than about its strategic positioning, so it should be described as an emerging developer rather than as a company with an already validated clinical product.

Phagos has initially chosen animal health as its route toward scalable personalized phage therapy. The company combines microbiology and artificial intelligence to select and design treatments adapted to bacterial pathogens and their evolution. It states that it has obtained authorization to market personalized phage-based veterinary treatments in the European Union and announced a €25 million Series A financing round to expand deployment, strengthen its artificial-intelligence platform and prepare future applications beyond veterinary medicine. Its model is strategically relevant because animal health offers an environment in which phage selection, rapid adaptation, field delivery and manufacturing can be developed at scale while contributing to reduced antibiotic consumption through a One Health framework.

GREENPHAGE develops selective antibacterial solutions based on virulent bacteriophages and phage-derived particles for environmental, agricultural, food-processing, veterinary and potential human-health applications. The company reported successful anti-Escherichia coli treatments in an industrial setting and announced a €1.9 million equity financing round within a broader financing plan of approximately €4 million. Its stated objectives include expanding treatment sites, strengthening research and commissioning a large-scale phage production unit in France. GREENPHAGE’s significance lies in its One Health and industrial-process orientation: it treats bacteriophages not only as medicines for individual patients but as precision biological agents capable of controlling defined bacterial populations in complex ecosystems.

Rime Bioinformatics occupies an enabling position within the ecosystem. Therapeutic phage development depends on accurate genome annotation, detection of lysogeny-associated genes, antimicrobial-resistance determinants, potential virulence factors and prophages present in bacterial production strains. These analyses are complicated by the enormous diversity of phage genomes and by the large proportion of genes whose functions remain unknown. Rime develops phage-focused genomic analysis and annotation services intended to support candidate selection, production-strain assessment and regulatory evidence packages. This type of company may not administer phages to patients, but it addresses a critical bottleneck between viral discovery and therapeutic qualification.

Vetophage focuses on animal health, rapid bacterial detection and phage-derived antibacterial proteins. Its platform combines phage banking with the identification and production of proteins capable of recognizing or destroying specific bacteria. The company is developing diagnostic tools that can support more targeted antibiotic use and therapeutic alternatives for veterinary infections, including mastitis and infections caused by staphylococci or enteric pathogens. Vetophage states that it controls activities from early research through protein production within an ISO 9001-certified system. Its work reinforces the One Health dimension of the French ecosystem by connecting phage biology with veterinary diagnostics, antimicrobial stewardship and alternatives to antibiotics.

These six companies should not be presented as interchangeable competitors. They occupy different positions along the value chain. Eligo develops engineered phage-derived genetic medicines. Phagenix is oriented toward human therapeutic phages. Phagos is building personalized veterinary treatment and AI-assisted selection. GREENPHAGE targets One Health and industrial bacterial control. Rime provides specialized genomic and bioinformatic qualification. Vetophage develops veterinary diagnostics and phage-protein therapeutics. Together, they demonstrate that France’s industrial phage capacity extends beyond the production of natural viral cocktails and already includes several of the technologies identified as priorities by Inserm.

The interaction between the three national pillars is where France’s strongest opportunity lies. Academic researchers can reveal receptors, defence systems, infection dynamics, immune responses and evolutionary trade-offs. Hospitals can provide clinical isolates, patient-centred questions, compassionate-treatment experience, pharmaceutical preparation and carefully monitored administration. Companies can convert these discoveries into scalable platforms, proprietary engineering methods, diagnostic tools, analytical services and investable development programmes. None of these sectors can build routine phage therapy independently.

Research without clinical integration risks producing phages that perform well only under simplified laboratory conditions. Hospitals without industrial or public production remain dependent on uncertain external supply. Industry without access to high-quality clinical isolates, mechanistic science and hospital networks may develop products poorly aligned with medical needs. The Inserm initiative can become the coordination layer connecting these capabilities, provided that companies, hospitals and academic institutions are involved through transparent rules for data sharing, intellectual property, manufacturing access and patient benefit.

France must still overcome important weaknesses. No phage medicinal product currently has a standard marketing authorization in the European Union. Clinical evidence remains heterogeneous, manufacturing is expensive and personalized adaptation challenges conventional pharmaceutical models. The French industrial sector is still small compared with established antibiotic or biologics industries, and several companies concentrate initially on animal, environmental or enabling applications rather than late-stage human therapeutics. Public manufacturing capacity in Lyon is a major achievement, but it must eventually be connected to multicentre demand, sustainable financing and broader pathogen coverage.

The Inserm programme will also need to avoid fragmentation within its own consortium. High-throughput screening, engineered phages, organoids, PK/PD models, social science and health economics can easily become parallel projects with limited integration. The programme will be most valuable if shared phages, bacterial panels, data standards and clinically defined use cases connect the work packages. A candidate identified through automated screening should be traceable through engineering, production, preclinical evaluation, pharmacological modelling and regulatory assessment. Clinical and experimental results should then return to the selection process, creating a continuous learning system.

France’s potential European leadership should therefore not be measured by the number of phages stored in its banks or the number of institutions carrying out isolated experiments. It should be measured by whether the country can build a complete, interoperable pathway from discovery to patient access. The foundations of such a pathway are now visible: fundamental and translational research coordinated by Inserm, long-standing expertise at Institut Pasteur and other universities, controlled compassionate access through the ANSM, clinical networks and public pharmaceutical production at the HCL, national programmes such as PHAG-ONE and THERAPhage, and a growing group of companies spanning human medicine, veterinary health, synthetic biology, artificial intelligence, genomics and bioproduction.

France is not alone in Europe, nor should its ambition be framed as replacing the expertise developed in Belgium, Germany, the Netherlands, Portugal, the United Kingdom, Switzerland, Georgia or other countries. European phage therapy will require shared collections, comparable susceptibility methods, harmonized manufacturing standards and multicentre clinical research. France’s opportunity is to become one of the countries capable of demonstrating how those elements can be integrated within a modern public-health and pharmaceutical system.

The historical symbolism is difficult to ignore. A century after Félix d’Hérelle helped establish the concept of using bacteriophages against bacterial infection in Paris, France is attempting to rebuild phage therapy using the scientific and regulatory tools of contemporary medicine. The new phase is not a return to the empirical practices of the early twentieth century. It is an effort to combine precision microbiology, synthetic biology, human-relevant models, pharmaceutical manufacturing, data science, regulatory oversight and health-system planning.

If Inserm succeeds in connecting its research programme with hospital production and a mature industrial ecosystem, France could become a European pioneer not because it claims ownership of phage therapy, but because it creates one of the first complete national systems capable of developing it responsibly. The country already possesses the essential components. The challenge of the coming years will be to make them function as one continuous chain, from the first environmental sample and the first genome sequence to the selection, production and administration of a therapeutic phage that reaches the right patient at the right time.

Sources :

1) Inserm, Programme d’impulsion Phagothérapie, June 2026: https://pro.inserm.fr/rubriques/appels-a-projets/programmes-de-linserm/programmes-d-impulsion/phagotherapie

2) Inserm, Les programmes d’impulsion: https://pro.inserm.fr/rubriques/appels-a-projets/programmes-de-linserm/programmes-d-impulsion/les-programmes-dimpulsion

3 Institut Pasteur, Bacteriophage, Bacterium, Host research group: https://research.pasteur.fr/en/team/bacteriophage-bacterium-host/

4) Hospices Civils de Lyon, authorization to manufacture therapeutic phages : https://teamhcl.chu-lyon.fr/autorisation-production-phages-therapeutiques

5) Hospices Civils de Lyon, PHAG-ONE: https://recherche.chu-lyon.fr/antibioresistance-projet-phag-one

6) Hospices Civils de Lyon, RHU THERAPhage: https://recherche.chu-lyon.fr/rhu-theraphage

7) ANSM, compassionate access to anti-Staphylococcus aureus bacteriophages: https://ansm.sante.fr/actualites/phagotherapie-lansm-autorise-un-acces-compassionnel-pour-des-bacteriophages-dans-les-infections-osteo-articulaires

8) Phage Atlas, global bacteriophage companies map: https://www.thephagetherapy.com/p/var-map-l.html 

9) Eligo Bioscience: https://eligo.bio/

10) Eligo Bioscience platform: https://eligo.bio/platform/

11) Eligo Bioscience study on in vivo bacterial genome editing: https://eligo.bio/eligo-nature-publication/

12) Phagenix: https://phagenix.com/en/

13) Phagenix phage therapy platform: https://phagenix.com/en/phage-therapy/

14) Phagos: https://www.phagos.com/about-us

15) Phagos Series A announcement: https://www.phagos.com/fr/resources/series-a-fundraising

16) GREENPHAGE: https://greenphage.com/

17) GREENPHAGE technologies: https://greenphage.com/technologies/

18) GREENPHAGE financing and industrial production announcement:

https://greenphage.com/fr/greenphage-leve-19-me-et-accelere-le-developpement-de-ses-solutions-antibacteriennes-naturelles/

19 Rime Bioinformatics: https://rime-bioinformatics.com/

20) Rime Bioinformatics phage therapy services: https://rime-bioinformatics.com/services-2-2/phage-therapy/

21) Rime Bioinformatics phage genome analysis pipeline: https://rime-bioinformatics.com/pipeline/

22) Vetophage: https://vetophage.fr/en/accueil-english/

23) Vetophage technology and One Health platform: https://vetophage.fr/en/who-are-we-2/