Key manufacturing and quality control (QC) elements in contemporary phage therapy frameworks.
| Manufacturing/QC component | Key regulatory or operational considerations | Illustrative examples/Reported practices | References |
|---|---|---|---|
| Host cell banks | Use of validated production hosts organized into master and working cell banks | Structured cell-banking systems reported in the Belgian compassionate-use program | [10] |
| Phage seed stocks | Controlled phage seed lots with genomic characterization and traceability | Seed-lot systems aligned with Ph. Eur. 5.31 expectations | [9] |
| Genomic safety screening | Screening for toxin genes, antimicrobial resistance determinants, lysogeny modules, and prophage contamination | The Belgian cohort screened both phages and production hosts against virulence and resistance databases | [10] |
| Potency testing | Standardized plaque assays or equivalent functional assays for titre determination | Clinical preparations generally ranged from ~106 to 1010 PFU/mL, depending on formulation and route | [8, 10, 39, 41] |
| Impurity and endotoxin control | Control of host-cell impurities, pyrogenicity testing, and endotoxin thresholds for systemic administration | Median endotoxin level of 5 EU/mL and weight-adjusted endotoxin thresholds reported in the Belgian program | [5, 10] |
| Microbiological quality/Sterility | Sterility requirements for sterile PTMPs and microbiological specifications for non-sterile formulations | Regulatory guidance from Ph. Eur. and EMA draft framework | [9, 11] |
| Stability testing | Stability evaluation for shelf life, storage, and transport conditions | EMA draft guidance includes structured stability assessment procedures | [11] |
| Change-control and platform reproducibility | Defined procedures for post-manufacturing updates and comparability management | Proposed platform-based lifecycle protocols permitting adaptive phage updates within validated manufacturing frameworks | [11, 19, 21, 35] |
Ph. Eur.: European Pharmacopoeia; EMA: European Medicines Agency.
The author acknowledges the use of Paperpal (https://paperpal.com/), an AI-powered academic tool, for language editing and academic paraphrasing to enhance the clarity and readability of the manuscript. The use of AI tools was strictly limited to linguistic refinement; all intellectual content, scientific interpretations, data analysis, and conclusions are entirely the authors’ own.
POO: Conceptualization, Investigation, Writing—original draft. TSF: Conceptualization, Investigation, Writing—original draft. OJO: Writing—original draft, Writing—review & editing. All authors have read and approved the final manuscript.
The authors declare that they have no conflicts of interest.
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