Expert view: Low Endotoxin Recovery (LER)

What is PDA TR82?

In March 2019, the PDA published TR82 on LER. The report constitutes a much‑needed source of information and guidance, including scientific findings on the mechanism behind the analytical issue. It also includes recommended procedures for analysis and mitigation of endotoxin masking commonly leading to LER in biologics. This comprehensive document is a result of three years intensive work completed by the PDA LER Task Force, which consists of members from the US FDA, academia, pharmaceutical industry and all endotoxin testing suppliers. TR82 is available in full for members and can be purchased directly from the PDA Technical Reports Portal.

What are TR82’s biggest takeaways?

TR82 is an important scientific and guidance document that will give pharmaceutical companies leverage for the successful mitigation of the LER phenomenon, with the ultimate outcome of increased process and product knowledge. Important takeaways of the report are: 1) a description of the underlying mechanisms and contributing factors of LER, 2) a summary of the potential clinical impact, 3) clear guidelines for conducting LER hold-time studies and 4) a choice of strategies for the mitigation of LER are made available for the industry.

What are the outcomes of Case Study 7: evaluation of an endotoxin demasking protocol, in TR82?

An important part of TR82 is the comprehensive appendix of case studies considering LER occurrences, encompassing both analyses of root-causes and endotoxin preparations, as well as methodologies for overcoming LER. In one of the studies, Case Study 7: evaluation of an endotoxin demasking protocol, the application of the ENDO-RS method, developed by Hyglos – a bioMérieux company, was assessed. This study used a sample known to be affected by LER to evaluate a sample preparation protocol using ENDO-RS reagents prior to detection of endotoxin using the LAL method. The results showed that the ENDO-RS protocol was able to reliably detect the endotoxin under all conditions tested, ensuring robust recovery and diminishing the risk of false‑negative test results.

What is the ENDO-RS^® method?

The ENDO-RS method is a patented set of reagents for sample preparation addressing the masking of endotoxin in biopharmaceutical formulations typically containing surfactants, chelating agents or specific active pharmaceutical ingredients (APIs). ENDO-RS enables full quantitative recovery of endotoxin prior to detection, independent of storage time and endotoxin concentration. bioMérieux provides specialised protocol development services applying ENDO-RS. Our work for leading pharmaceutical companies has resulted in validated methods for LER, fulfilling regulatory requirements.