Question: If Chapter <86> Bacterial Endotoxins Test using Recombinant Reagents is a below 1000 chapter, why is it necessary to complete additional verification as specified in the chapter?
Answer: At the present time, the methods in Chapter <86> are considered to be alternative methods to Chapter <85>Bacterial Endotoxins Test (BET). The definition of an alternative method can be found in General Notices 6.30:
“An alternative method or procedure is defined as any method or procedure other than the compendial method or procedure for the article in question.”
Because Chapter <86> contains alternative methods, it is the responsibility of the user to confirm a method’s suitability for use in testing specific products or materials by ensuring that the primary method (non-product specific method) is validated (in accordance with <1225> Validation of Compendial Procedures and the method is verified as suitable for the product/material being tested (in accordance with <1226> Verification of Compendial Procedures. For Chapter <86>, the vendor's primary validation of the test kit should be evaluated to determine if it complies with the requirements of method validation required in USP <1225>. Compliance with the requirements for compendial method verification (Chapter <1226> is included in the Chapter <86> section Preparatory Testing.
As described in Chapter <86>, the user needs to review the primary validation package provided by the vendor (or developed internally) to ensure the validation status of the method is suitable for its intended use. Successful completion of these steps (primary validation review and successful completion of the Preparatory Testing in Chapter <86>) can be used to demonstrate that the method selected is appropriate for the specific material being tested. As experience with the use of these reagents has been limited to date, regulatory authorities may require additional specific verification data prior to acceptance.
Question: Is <86> harmonized with Ph.Eur. 2.6.32? If not, can it be?
Answer: For USP standards, cross-pharmacopoeia harmonization occurs through the Pharmaceutical Discussion Group (PDG) in alignment with ICH Q4B. Bacterial Endotoxins Tests in the United States Pharmacopeia (USP), European Pharmacopoeia (EP), Indian Pharmacopoeia Commission (IPC), and Japanese Pharmacopoeia (JP) using horseshoe crab-sourced test reagents are harmonized, bringing significant benefit to end users operating around the globe and across markets recognizing major pharmacopoeias. Harmonization via PDG is achievable and desired; efforts are underway to open the discussion for future harmonization with PDG.
Question: Why were recombinant reagents not added to <85>?
Answer: Because <85> is a harmonized chapter with corresponding chapters in Europe, India, and Japan. These chapters are part of ICH Q4B, which implies that they are considered interchangeable within the regulators in the ICH regions. Therefore, it is more difficult to make changes in a timely manner. Harmonizing current and future rBET chapters is desired; refer to the question above regarding harmonization.
Question: How would USP evaluate study data in multiple products and materials to justify establishing <86> as an applicable chapter?
Answer: The Endotoxins and Pyrogens Subcommittee of the USP General Chapters Microbiology Expert Committee developed Chapter <86> based on the collective expertise of the subcommittee, the available peer-reviewed literature, extensive review of public and submitted confidential end-user data and validations, and input from the government liaisons. Continued generation of rBET data and submission to the global compendia will enable the establishment of applicability across products.
Question: Why were recombinant Cascade Reagents (rCR) included in <86>?
Answer: The Endotoxin Subcommittee to the USP Microbiology Expert Committee (MEC) developed Chapter <86> based on an extensive review of public and submitted confidential end-user data and validations, and the available peer-reviewed literature. Extensive data exists in the peer-reviewed literature for the BET using rFC and rCRs, and the MEC was also able to review non-public/confidential data during the development of the chapter. This information was considered in combination with the recognition that recombinant reagents are the biotechnology equivalent of natural Factor C, the biosensor responsible for endotoxin detection in horseshoe crabs. Additionally, the rCR enzymatic cascade begins with rFC. Combining all of this information and data, the MEC agreed that the inclusion of rCR was supported by the science and data reviewed. Advancing an rBET chapter is aligned with USP’s commitment to expanding the use of animal-free methods and materials.
Question: Are extensive comparability/equivalency studies needed to justify transitioning from <85> to <86>?
Answer: Extensive comparability/equivalency studies are not warranted for most products tested for endotoxins. In most cases, a demonstration of product-specific method suitability will be sufficient, which in practice is similar to <85>. There may always be exceptions, and those should be based on end-user experience and material characteristics. In some cases, a proactive review of the approach may be done with the relevant regulatory authority. Chapter <86> employs the same endotoxin tolerance limit, measurement units, and primary reference standard as Chapter <85>. This is in contrast with the implementation of Chapter <85> when endotoxin testing transitioned from the Rabbit Pyrogen Test (RPT), which did not have these quality control features and only included animal husbandry best practices. Furthermore, the rBET is built on decades-long, well-established biotechnology science that begins with the same mechanism-of-action: rFC is the clone of horseshoe crab Factor C, and the detection of bacterial endotoxins occurs via biosensor horseshoe crab Factor C.
Question: Does the implementation of <86> impact the use of USP Chapter <151> Pyrogen Test?
Answer: The introduction of Chapter <86> is the first step in developing non-animal testing models by the USP MEC. While the introduction of Chapter <86> has no direct impact on Chapter <151>, it provides a framework for introducing new technologies that can be used instead of animal testing models. With the support of the MEC stakeholders, other technologies (e.g., the Monocyte Activation Test, MAT) are being explored for future introduction. The addition of new in vitro technologies and/or instrumental techniques is part of USP’s commitment to expanding the use of animal-free methods and materials.
Posted November 1, 2024