Annex 1 Revision Encourages the Use of Rapid Methods

The final revision to Annex 1 "Manufacture of Sterile Medicinal Products," under the The Rules Governing Medicinal Products in the European Union Volume 4 EU Guidelines for Good Manufacturing Practice for Medicinal Products for Human and Veterinary Use, went into effect on August 25, 2023. The revision may be downloaded here: https://health.ec.europa.eu/system/files/2022-08/20220825_gmp-an1_en_0.pdf.

Quality Benefits Realized

The new revision highlights the quality benefits of employing rapid methods in place of slower, conventional methods for the detection of contaminants. Specifically,

• "The use of appropriate technologies (e.g. Restricted Access Barriers Systems (RABS), isolators, robotic systems, rapid/alternative methods and continuous monitoring systems) should be considered to increase the protection of the product from potential extraneous sources of endotoxin/pyrogen, particulate and microbial contamination such as personnel, materials and the surrounding environment, and assist in the rapid detection of potential contaminants in the environment and the product."


• "The adoption of suitable alternative monitoring systems such as rapid methods should be considered by manufacturers in order to expedite the detection of microbiological contamination issues and to reduce the risk to product. These rapid and automated microbial monitoring methods may be adopted after validation has demonstrated their equivalency or superiority to the established methods."


• "For products with short shelf life, the environmental data for the time of manufacture may not be available; in these cases, the compliance should include a review of the most recent available data. Manufacturers of these products should consider the use of rapid/alternative methods."

Say Goodbye to the CFU for Environmental Monitoring Limits

Some of the most encouraging changes are associated with the use of rapid methods instead of the standard methods for environmental monitoring. For example, one of the notes in Table 2, which discusses the maximum permitted microbial contamination level during qualification of a cleanroom, states, "Limits are applied using CFU throughout the document. If different or new technologies are used that present results in a manner different from CFU, the manufacturer should scientifically justify the limits applied and where possible correlate them to CFU."

Therefore, the EU allows us to revise the numerical values for the CFU-based maximum permitted microbial contamination level to new numerical values based on a rapid method's alternative microbial detection signal. One example of a new rapid signal is an intrinsic fluorescent count which can be derived in real-time and does not require growth on conventional microbiological media.

Similar guidance on the use of alternative limits is provided in the footnotes for Table 6, which discusses the maximum action limits for viable particle contamination during routine manufacturing. Additionally, although the table provides CFU-based limits for active air samples, settle plates, contact plates and glove prints, one footnote allows for the use of methods other than those specified in the table.

Specifically, "[i]t should be noted that the types of monitoring methods listed in the table above are examples and other methods can be used provided they meet the intent of providing information across the whole of the critical process where product may be contaminated (e.g. aseptic line set-up, aseptic processing, filling and lyophilizer loading)."

Swiss Authority Publishes Q&A Document on Interpreting the Revision ^st Century

On October 31, 2023, Swissmedic (SMI) published a document on how to interpret the revisions to Annex 1. Specifically, the document states,

• "This technical interpretation focuses on some of the most important changes of the 2022 revision of Annex 1 and also covers aspects that were already included in the previous version of this guidance document and that have repeatedly raised questions. This technical interpretation is intended to reflect the general opinion of the Swiss Inspectorates on these issues and to assist in the inspection of manufacturers of sterile medicinal products."

Relevant to rapid methods, the following question was posed:

• Is it possible to fully replace microbiological monitoring using e.g. settle plates and volumetric air sampling systems, by other integrated sampling and testing systems (e.g. Rapid Microbiological Methods, RMM)?

SMI provided the following guidance in answering this question:

• Paragraph 9.22 requires a microbial monitoring using a combination of methods such as settle plates, volumetric air sampling, glove, gown and surface sampling.
• New technologies are available as continuous active air sampling and rapid microbial testing systems, e.g., based on digital imaging technology to detect and count growing microbes.
• Equivalence of methods should be demonstrated and the effectiveness of the chosen method should be proven, including for in-house germs.
• Validation data of these new methods should include recovery studies of the sampling method.
• The exposure time should not have any negative effect on the suitability of the media used.
• For the use of real-time viable particle counting and given the non-equivalency Auto-Fluorescent Unit (AFU) versus CFUs and current GMP / Pharmacopeial limits are in CFU, the company needs to collect data on their process for the real-time viable particle counting to compare it to the standard environmental monitoring data.
• A full understanding of what triggers signals and what is a normal AFU signal in the process and the development of appropriate alert and action limits based on this data, together with appropri-ate procedures that should define the actions to be taken in response to alarms including the consideration of additional microbial monitoring must be established. A scientific justification for the limits applied is required. Data must be available for at least 12 months.
• Required elements the company needs to have:
  Primary Validation Package of the vendor for the system
  User specific Validation Package / Data for Verification of Validation
  • Parallel phase grade A (RRM/traditional active air sampling method) in operation to gain experience with new technology under grade A
  • Test for interferences to be addressed, e.g., by disinfectants, materials or product
  Operational Approach: Implementation / Alarm Handling Concept
  Supportive data: Collection and evaluation of data in a production area grade C and D
• Identification of microorganisms must be per-formed as it is essential to determine the (possi-ble) root cause of a contamination and evaluate the risk of the contamination for the drug prod-uct. If an action limit exceedance occurs, the agar plate from the system must be incubated in order to isolate associated CFUs and to allow identification of species for further investigation and impact assessment of product quality.

Annex 1 Moves Microbiology into the 21^st Century

The finalization of this long-awaited revision is welcomed and demonstrates the EU's commitment to advancing the detection of microorganisms during sterile drug manufacturing by encouraging and implementing next generation rapid microbiological methods.