Quis Custodiet? Are Regulations Slowing Phage Therapy?

Wiebe K.G., Cook B.W., Lightly T.J., Court D.A., Theriault S.S.

AbstractAs the demand for bacteriophage (phage) therapy increases due to antibiotic resistance in microbial pathogens, strategies and methods for increased efficiency, large-scale phage production need to be determined. To date, very little has been published on how to establish scalable production for phages, while achieving and maintaining a high titer in an economical manner. The present work outlines a phage production strategy using an enterotoxigenic Escherichia coli-targeting phage, ‘Phage75’, and accounts for the following variables: infection load, multiplicity of infection, temperature, media composition, harvest time, and host bacteria. To streamline this process, variables impacting phage propagation were screened through a high-throughput assay monitoring optical density at 600 nm (OD600) to indirectly infer phage production from host cell lysis. Following screening, propagation conditions were translated in a scalable fashion in shake flasks at 0.01 L, 0.1 L, and 1 L. A final, proof-of-concept production was then carried out in a CellMaker bioreactor to represent practical application at an industrial level. Phage titers were obtained in the range of 9.5–10.1 log10 PFU/mL with no significant difference between yields from shake flasks and CellMaker. Overall, this suggests that the methodology for scalable processing is reliable for translating into large-scale phage production.

Karn S.L., Bhartiya S.K., Pratap A., Saroj S.K., Kumar R., Sahu M., Gangwar M., Nath G.

Background Chronic wounds are prevalent globally at endemic proportions. The common features associated with chronic wounds are prolonged inflammatory phase, infection with multidrug-resistant (MDR) bacteria, and subsequent biofilm formation. The present randomized-controlled trial (RCT) study was undertaken on chronic wounds of ≥6 weeks longer duration using customized phages to evaluate the efficacy and safety of bacteriophage therapy. Methods The study was conducted from December 2021 to August 2023. Thirty patients in each of the arms (placebo and bacteriophage) were recruited with chronic wounds. The patients, both arms, received the conventional treatment of wound debridement, local antiseptics, and local and systemic antibiotics at the discretion of the treating surgeon. However, before applying the customized bacteriophage cocktail or placebo, the wound surface was thoroughly washed to remove the residual antiseptics. The phage cocktails or placebo were applied on alternate days. The wounds were evaluated using the Bates-Jensen Wound Assessment Tool for the progress of wound healing. Results A total of 93.3% of the wound became sterile in 39 days (median sterility time), followed by complete healing by the end of 90 days in the phage group. Contrary to this, 83.3% of those on placebo therapy remained colonized by original bacteria or additional new bacteria without healing for up to 90 days. Conclusion With the well-designed RCT, we could conclude that customized bacteriophage therapy using bacteriophage cocktails will definitely cure the chronic wound, irrespective of age, sex, diabetes status, and infection by MDR bacteria.

Sillankorva S., Hyman P.

The isolation of bacteriophages targeting most clinically relevant bacteria is reasonably straightforward as long as its targeted host does not have complex chemical, physical, and environmental requirements. Often, sewage, soil, feces, and different body fluids are used for bacteriophage isolation procedures, and following enrichment, it is common to obtain more than a single phage in a sample. This chapter describes a simple method for the enrichment and isolation of bacteriophages from liquid and solid samples that can be adapted for different clinically important aerobic bacteria.

Pirnay J., Verbeken G.

Abstract Phage therapy is increasingly put forward as a promising additional tool to help curb the global antimicrobial resistance crisis. However, industrially manufactured phage medicinal products are currently not available on the European Union and United States markets. In addition, it is expected that the business purpose–driven phage products that are supposed to be marketed in the future would mainly target commercially viable bacterial species and clinical indications, using fixed phage cocktails. hospitals or phage therapy centers aiming to help all patients with difficult-to-treat infections urgently need adequate phage preparations. We believe that national solutions based on the magistral preparation of personalized (preadapted) phage products by hospital and academic facilities could bring an immediate solution and could complement future industrially manufactured products. Moreover, these unlicensed phage preparations are presumed to be more efficient and to elicit less bacterial phage resistance issues than fixed phage cocktails, claims that need to be scientifically substantiated as soon as possible. Just like Belgium, other (European) countries could develop a magistral phage preparation framework that would exist next to the conventional medicinal product development and licensing pathways. However, it is important that the current producers of personalized phage products are provided with pragmatic quality and safety assurance requirements, which are preferably standardized (at least at the European level), and are tiered based on benefit–risk assessments at the individual patient level. Pro bono phage therapy providers should be supported and not stopped by the imposition of industry standards such as Good Manufacturing Practice requirements. Keywords: antimicrobial resistance; antibiotic resistance; bacterial infection; bacteriophage therapy; magistral preparation.

Jain N., Umar T.P., Fahner A., Gibietis V.

Hitchcock N.M., Devequi Gomes Nunes D., Shiach J., Valeria Saraiva Hodel K., Dantas Viana Barbosa J., Alencar Pereira Rodrigues L., Coler B.S., Botelho Pereira Soares M., Badaró R.

In response to the global spread of antimicrobial resistance, there is an increased demand for novel and innovative antimicrobials. Bacteriophages have been known for their potential clinical utility in lysing bacteria for almost a century. Social pressures and the concomitant introduction of antibiotics in the mid-1900s hindered the widespread adoption of these naturally occurring bactericides. Recently, however, phage therapy has re-emerged as a promising strategy for combatting antimicrobial resistance. A unique mechanism of action and cost-effective production promotes phages as an ideal solution for addressing antibiotic-resistant bacterial infections, particularly in lower- and middle-income countries. As the number of phage-related research labs worldwide continues to grow, it will be increasingly important to encourage the expansion of well-developed clinical trials, the standardization of the production and storage of phage cocktails, and the advancement of international collaboration. In this review, we discuss the history, benefits, and limitations of bacteriophage research and its current role in the setting of addressing antimicrobial resistance with a specific focus on active clinical trials and case reports of phage therapy administration.

Gómez-Ochoa S.A., Pitton M., Valente L.G., Sosa Vesga C.D., Largo J., Quiroga-Centeno A.C., Hernández Vargas J.A., Trujillo-Cáceres S.J., Muka T., Cameron D.R., Que Y.

Antimicrobial resistance of bacterial pathogens is an increasing clinical problem and alternative approaches to antibiotic chemotherapy are needed. One of these approaches is the use of lytic bacterial viruses known as phage therapy. We aimed to assess the efficacy of phage therapy in preclinical animal models of bacterial infection.In this systematic review and meta-analysis, MEDLINE/Ovid, Embase/Ovid, CINAHL/EbscoHOST, Web of Science/Wiley, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Google Scholar were searched from inception to Sept 30, 2021. Studies assessing phage efficacy in animal models were included. Only studies that assessed the efficacy of phage therapy in treating established bacterial infections in terms of survival and bacterial abundance or density were included. Studies reporting only in-vitro or ex-vivo results and those with incomplete information were excluded. Risk-of-bias assessment was performed using the Systematic Review Centre for Laboratory Animal Experimentation tool. The main endpoints were animal survival and tissue bacterial burden, which were reported using pooled odds ratios (ORs) and mean differences with random-effects models. The I2 measure and its 95% CI were also calculated. This study is registered with PROSPERO, CRD42022311309.Of the 5084 references screened, 124 studies fulfilled the selection criteria. Risk of bias was high for 70 (56%) of the 124 included studies; therefore, only studies classified as having a low-to-moderate risk of bias were considered for quantitative data synthesis (n=32). Phage therapy was associated with significantly improved survival at 24 h in systemic infection models (OR 0·08 [95% CI 0·03 to 0·20]; I2=55% [95% CI 8 to 77]), skin infection (OR 0·08 [0·04 to 0·19]; I2 = 0% [0 to 79]), and pneumonia models (OR 0·13 [0·06 to 0·31]; I2=0% [0 to 68]) when compared with placebo. Animals with skin infections (mean difference -2·66 [95% CI -3·17 to -2·16]; I2 = 95% [90 to 96]) and those with pneumonia (mean difference -3·35 [-6·00 to -0·69]; I2 = 99% [98 to 99]) treated with phage therapy had significantly lower tissue bacterial loads at 5 ± 2 days of follow-up compared with placebo.Phage therapy significantly improved animal survival and reduced organ bacterial loads compared with placebo in preclinical animal models. However, high heterogeneity was observed in some comparisons. More evidence is needed to identify the factors influencing phage therapy performance to improve future clinical application.Swiss National Foundation and Swiss Heart Foundation.

Stacey H.J., De Soir S., Jones J.D.

Trials of phage therapy have not consistently reported efficacy. This contrasts with promising efficacy rates from a sizeable and compelling body of observational literature. This systematic review explores the reasons why many phage trials have not demonstrated efficacy. Four electronic databases were systematically searched for safety and/or efficacy trials of phage therapy. Sixteen trials of phage therapy were included, in which 378 patients received phage. These were divided into historical (pre-2000; N = 3; n = 76) and modern (post-2000; N = 13; n = 302) trials. All 13 modern trials concluded that phage therapy was safe. Six of the 13 modern trials were exclusively safety trials. Seven modern trials investigated both safety and efficacy; efficacy was observed in two. Two of three historical trials did not comment on safety, while adverse effects in the third likely reflected the use of phage preparations contaminated with bacterial debris. None of the historical trials contained evidence of efficacy. The evidence from trials is that phage therapy is safe. For efficacy to be observed a therapeutic amount of the right phage(s) must be delivered to the right place to treat infections containing enough susceptible bacterial cells. Trials that have not demonstrated efficacy have not fulfilled one or more elements of this principle.

Żaczek M., Górski A., Weber-Dąbrowska B., Letkiewicz S., Fortuna W., Rogóż P., Pasternak E., Międzybrodzki R.

The year 2020 marked 15 years of the Phage Therapy Unit in Poland, the inception of which took place just one year after Poland’s accession to the European Union (2004). At first sight, it is hard to find any connection between these two events, but in fact joining the European Union entailed the need to adapt the regulatory provisions concerning experimental treatment in humans to those that were in force in the European Union. These changes were a solid foundation for the first phage therapy center in the European Union to start its activity. As the number of centers conducting phage therapy in Europe and in the world constantly and rapidly grows, we want to grasp the opportunity to take a closer look at the over 15-year operation of our site by analyzing its origins, legal aspects at the local and international levels and the impressive number and diversity of cases that have been investigated and treated during this time. This article is a continuation of our work published in 2020 summarizing a 100-year history of the development of phage research in Poland.

Nagel T., Musila L., Muthoni M., Nikolich M., Nakavuma J.L., Clokie M.R.

Lower and middle-income countries seldom develop vaccines and therapeutics for their own populations and are dependent on supplies from industrialized countries, which are often hampered by financial or supply chain limitations. This has resulted in major delays in delivery with significant loss of life, as seen with the coronavirus pandemic. Since the vast majority of deaths from the antimicrobial resistance crisis are expected to occur in developing countries, there is an urgent need for in-country production of antibacterial therapies such as phages. Nationally controlled phage banks might provide such a solution since locally developed phage therapies tailored to endemic bacterial strains could offer cost-effective antibiotic alternatives.

Verbeken G., Pirnay J.

Bacteriophages (phages) are bacterial viruses, and have been used for more than a century to combat bacterial infections, particularly in Poland and in the former Soviet Union. The antimicrobial resistance crisis has triggered a renewed interest in the therapeutic use of natural phages. The capacity of phages to specifically target pathogenic strains (sparing commensal bacteria), to adapt to these strains, and to rapidly overcome bacterial resistance, makes them suitable for flexible therapeutic approaches. To maximally exploit these advantages phages offer over conventional 'static' drugs such as traditional small molecule-type antibiotics, it is important that these sustainable phage products are not submitted to the traditional (long and expensive) medicinal product development and licensing pathways. Here we discuss the extrapolation of the Belgian 'magistral preparation' phage therapy framework to the European level, enabling an expeditious re-introduction of personalized phage therapy into Europe.

Leitner L., Ujmajuridze A., Chanishvili N., Goderdzishvili M., Chkonia I., Rigvava S., Chkhotua A., Changashvili G., McCallin S., Schneider M.P., Liechti M.D., Mehnert U., Bachmann L.M., Sybesma W., Kessler T.M.

Summary Background Urinary tract infections (UTIs) are among the most prevalent microbial diseases and their financial burden on society is substantial. In the context of increasing antibiotic resistance, finding alternative treatments for UTIs is a top priority. We aimed to determine whether intravesical bacteriophage therapy with a commercial bacteriophage cocktail is effective in treating UTI. Methods We did a randomised, placebo-controlled, clinical trial, at the Alexander Tsulukidze National Centre of Urology, Tbilisi, Georgia. Men older than 18 years of age, who were scheduled for transurethral resection of the prostate (TURP), with complicated UTI or recurrent uncomplicated UTI but no signs of systemic infection, were allocated by block randomisation in a 1:1:1 ratio to receive intravesical Pyo bacteriophage (Pyophage; 20 mL) or intravesical placebo solution (20 mL) in a double-blind manner twice daily for 7 days, or systemically applied antibiotics (according to sensitivities) as an open-label standard-of-care comparator. Urine culture was taken via urinary catheter at the end of treatment (ie, day 7) or at withdrawal from the trial. The primary outcome was microbiological treatment response after 7 days of treatment, measured by urine culture; secondary outcomes included clinical and safety parameters during the treatment period. Analyses were done in a modified intention-to-treat population of patients having received at least one dose of the allocated treatment regimen. This trial is registered with ClinicalTrials.gov , NCT03140085 . Findings Between June 2, 2017, and Dec 14, 2018, 474 patients were screened for eligibility and 113 (24%) patients were randomly assigned to treatment (37 to Pyophage, 38 to placebo, and 38 to antibiotic treatment). 97 patients (28 Pyophage, 32 placebo, 37 antibiotics) received at least one dose of their allocated treatment and were included in the primary analysis. Treatment success rates did not differ between groups. Normalisation of urine culture was achieved in five (18%) of 28 patients in the Pyophage group compared with nine (28%) of 32 patients in the placebo group (odds ratio [OR] 1·60 [95% CI 0·45–5·71]; p=0·47) and 13 (35%) of 37 patients in the antibiotic group (2·66 [0·79–8·82]; p=0·11). Adverse events occurred in six (21%) of 28 patients in the Pyophage group compared with 13 (41%) of 32 patients in the placebo group (OR 0·36 [95% CI 0·11–1·17]; p=0·089) and 11 (30%) of 37 patients in the antibiotic group (0·66 [0·21–2·07]; p=0·47). Interpretation Intravesical bacteriophage therapy was non-inferior to standard-of-care antibiotic treatment, but was not superior to placebo bladder irrigation, in terms of efficacy or safety in treating UTIs in patients undergoing TURP. Moreover, the bacteriophage safety profile seems to be favourable. Although bacteriophages are not yet a recognised or approved treatment option for UTIs, this trial provides new insight to optimise the design of further large-scale clinical studies to define the role of bacteriophages in UTI treatment. Funding Swiss Continence Foundation, the Swiss National Science Foundation, and the Swiss Agency for Development and Cooperation. Translations For the Georgian and German translations of the abstract see Supplementary Materials section.

Huemer M., Mairpady Shambat S., Brugger S.D., Zinkernagel A.S.

Żaczek M., Weber-Dąbrowska B., Międzybrodzki R., Łusiak-Szelachowska M., Górski A.

Although phage discovery is an unquestionable merit of the English bacteriologist Frederick W. Twort and a Canadian-French microbiologist Félix d'Hérelle, who both discovered phage over 100 years ago, the Polish history of phage studies also dates back to those years. Contrary to the Western world, developing phage treatment in Poland has never been abandoned despite the country’s tense history marked by the Second World War and the communism era. Today, Poland takes a prominent and remarkable place in the phage research area. Furthermore, established in 2005, the Phage Therapy Unit at the Hirszfeld Institute of Immunology and Experimental Therapy in Wrocław, the first such center within European borders, has quickly become a model for other centers in the world facing the issue of wide-spread antibiotic resistance. This article constitutes an attempt to fill the gap in the scientific literature by providing a comprehensive summary of the long tradition of phage research in Poland.

Bretaudeau L., Tremblais K., Aubrit F., Meichenin M., Arnaud I.

Facing the emergence of difficult-to-treat bacterial infections, the perspective of using bacteriophages has re-gained interest in many countries. In terms of pharmaceutical classification in EU and USA, phages are considered as anti-infectious medicinal products and biological products, given the intended use and their live nature. During the production steps, the compliance with the Good Manufacturing Practice (GMP) represents the gold-standard to ensure the quality, safety and efficacy of medicinal products, either investigational or approved. In practice, the implementation of GMP rules for phage therapy medicinal products benefits from the long history of vaccine development. Accordingly, a well-structured strategy can be defined for each medicinal product, taking into account the specified indication (i.e. the target bacteria species, the infected site, the route of administration, the product composition). Based on the experience of different phage therapy medicinal products from the recent years, the most important requirements to achieve and claim GMP grade are reviewed here, including for genetically-modified phages. Like all new medicinal products, the manufacturing of investigational phages incorporates significant challenges. However, the use of GMP-certified phages provides the best guarantee for the rigorous assessment of quality, safety and efficacy during the clinical development of phage medicinal products, thus appears as a key component for the successful development of phage therapy approaches.