Demonstrating Results Equivalence of Bacterial Endotoxins Test Methods

Innovation is an important and necessary part of continuous improvement in the Pharmaceutical Industry. After the original early 20th century observations of ″injection fever″ caused by Gram negative bacterial endotoxins, we have seen the introduction of the Rabbit Pyrogen Test (RPT) into the United States Pharmacopeia (USP) in 1942, the introduction of the Limulus Lysate Test in 1973 and now the introduction of a number of new methods and platforms that do not rely on animals as either test subjects or reagent source. However innovative the alternate method, we must be cognizant of our obligation to patient safety and heed compendial and compliance requirements to demonstrate results equivalence between any candidate (alternate) method and a predicate (compendial) test method. Demonstrating that a candidate test method is equivalent to an existing predicate test method is never a trivial matter. However, given the inherent variability in test methods dependent on microbial growth, the task becomes even more complex. The following discussion explores the concepts of ″equivalent″ and ″not different″, proposes the use of a two one sided (TOST) test for the demonstration of equivalence and provides examples of calculations using commercially available software to assess data on alternative endotoxins detection methods that have been published in the public domain.