New approaches for biomarker stability determination in regulated bioanalysis: trending, bridging and incurred samples.

Aim: Determining the stability of biomarkers continues to present challenges. Disease states, complex matrices and differences between recombinant and endogenous analytes require new approaches to maintain stability and measure it. In this report, we determine stability for two assays using trending and statistical analysis. Methodology & results: Monitoring trends helps identify out of specification measurements and determine whether concerns are due to the stability of the analyte. We also describe challenges presented when measuring arginase activity in human sputum, a complex matrix, for respiratory diseases. We controlled preanalytical protease activity and collection heterogeneity and monitored incurred sample stability to improve stability of arginine. Conclusion: These new approaches to achieving and determining biomarker stability may provide solutions for increasingly complex biomarker measurements.

Adaptation of commercial biomarker kits and proposal for 'drug development kits' to support bioanalysis: call for action.

There has been an increased use of commercial kits for biomarker measurement, commensurate with the increased demand for biomarkers in drug development. However, in most cases these kits do not meet the quality attributes for use in regulated environment. The process for adaptation of these kits can be frustrating, time consuming and resource intensive. In addition, a lack of harmonized guidance for the validation of biomarker poses a significant challenge in the adaptation of kits in a regulated environment. The purpose of this perspective is to propose a tiered approach to commercial drug development kits with clearly defined quality attributes and to demonstrate how these kits can be adapted to perform analytical validation in a regulated environment.