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Bacterial Endotoxins Test (BET): USP Requests Additional Data for the Comparability of Recombinant Reagents to Compendial Reagents

Type of Posting: General Announcement
Posting Date: 11–Jun–2021

USP is interested in understanding the equivalence of test results obtained using recombinant reagents and lysate reagents as described in <85> Bacterial Endotoxins Test.  For that purpose, we are requesting that anyone who has performed comparability experiments to consider sharing the data with USP.

Several studies have been conducted and published and after considerable review, the USP Expert Committee (EC) determined that these studies are not sufficient to demonstrate the equivalence in test results between recombinant reagents and lysate reagents described in <85>. The main reasons for the need for new data are:

  • Many published studies tested samples that do not contain detectable levels of endotoxins activity, meaning that quantitation and comparison of the test results of the different reagents is not possible.
  • Most of the published data demonstrate method suitability, not comparability to the existing compendial method(s). Both of these assay attributes are required by General Notices 6.30 Alternative and Harmonized Methods and Procedures, <1225> Validation of Compendial Procedures, and <1223> Validation of Alternative Microbiological Methods. For clarification:
    • Suitability is the ability of the method to recover a KNOWN level of a KNOWN calibration analyte from a KNOWN and well-pedigreed microorganism. This experiment is not representative of endotoxins from autochthonous microorganisms that may be present in the pharmaceutical manufacturing environment.
    • Comparability is demonstration of the statistical equivalence of actual test results of UNKNOWN levels of endotoxins activity from UNKNOWN sources, meaning endotoxins activity from any number of autochthonous microorganisms which may have adapted to the manufacturing environment.
  • In most of these published studies, the sample size is not statistically significant.
  • Most of the published studies used either one or two commercial recombinant reagents, generally recombinant Factor C reagents. A comprehensive study requires the use of all available recombinant methods and all available LAL methods to collect sufficient data for comparability.
  • Samples used in the comparability study may contain both autochthonous endotoxins and glucans, therefore, it is important to know if a glucan blocker was used for lysate reagents.

If your organization has any data that meets the requirements described above, please consider submitting them, in CONFIDENCE, to USP to be used solely for the purposes of method evaluation. USP has established policies and rules that provide the highest safeguards to maintain confidentiality for methods or data submitted by stakeholders.

Questions and submissions may be directed to Leslie Furr, Senior Scientist I (