Contributions
Abstract: P1174
Type: Poster Sessions
Abstract Category: Pathology and pathogenesis of MS - Biomarkers
Background: Neurofilament (Nf) is a biomarker of axonal damage and emerging data indicates that serum Nf is associated with multiple sclerosis (MS) disease activity. However, the clinical utility of serum Nf for decision-making in drug development and individual patient monitoring remains to be determined. Clinical qualification of a biomarker for decision-making requires both an understanding of the biomarker biology in the disease setting as well as characterization of the assay analytical performance.
Objective: Selection and characterization of serum Nf assays, based on industry best practices for biomarker assay validation, to inform MS drug development and patient management.
Methods: Analytical characterization of selected assay platforms (NfL on Quanterix's Simoa and NfH on Protein Simple's Ella) included evaluation of accuracy (bias), intra/inter-assay precision, analytical range, parallelism, selectivity, and stability. Accuracy and precision was assessed with spiked and endogenous quality controls (QCs) at multiple levels to reflect the range of expected values in MS patients. MS serum was used to assess NfL and NfH stability and evaluate parallelism, informing dilution requirements, selectivity, and endogenous analyte assay sensitivity.
Results: The analytical ranges for both NfL and NfH assays were appropriate for the expected values in MS patients. Serum NfH assay sensitivity was determined to be 7.5 pg/mL, accuracy and precision met the performance criteria, and serum NfH was stable under all conditions tested, including multiple freeze-thaw cycles. Serum NfL assay sensitivity was determined to be 0.7 pg/mL and serum NfL was stable under all conditions tested. While the Simoa NfL assay demonstrated reproducible calibrator performance, two key observations impacted the accuracy and precision of NfL measurements: (1) inter-assay bias in spiked QC preparation and (2) a position-effect bias for endogenous and spiked QCs. To mitigate these effects, QCs for batch acceptance were prepared in bulk and calibrators and samples were strategically placed to distribute the position-effect bias.
Conclusions: While the NfH assay met the necessary performance requirements, the NfL assay required mitigation strategies to manage analytical issues that could have profound impact on clinical data analyses.
Supported by: Biogen.
Disclosure: Ankur Sharma: employee of Biogen and holds stock/stock options in Biogen
Marco Petrillo: employee of Biogen and holds stock/stock options in Biogen
Guolin Zhao: employee of Biogen and holds stock/stock options in Biogen
Jake Gagnon: employee of Biogen and holds stock/stock options in Biogen
Tatiana Plavina: employee of Biogen and holds stock/stock options in Biogen
Carol Singh: employee of Biogen and holds stock/stock options in Biogen
Ray Su: employee of Biogen and holds stock/stock options in Biogen
Chris Stebbins: employee of Biogen and holds stock/stock options in Biogen
Lauren Stevenson: employee of Biogen and holds stock/stock options in Biogen
Devangi Mehta: employee of Biogen and holds stock/stock options in Biogen
Abstract: P1174
Type: Poster Sessions
Abstract Category: Pathology and pathogenesis of MS - Biomarkers
Background: Neurofilament (Nf) is a biomarker of axonal damage and emerging data indicates that serum Nf is associated with multiple sclerosis (MS) disease activity. However, the clinical utility of serum Nf for decision-making in drug development and individual patient monitoring remains to be determined. Clinical qualification of a biomarker for decision-making requires both an understanding of the biomarker biology in the disease setting as well as characterization of the assay analytical performance.
Objective: Selection and characterization of serum Nf assays, based on industry best practices for biomarker assay validation, to inform MS drug development and patient management.
Methods: Analytical characterization of selected assay platforms (NfL on Quanterix's Simoa and NfH on Protein Simple's Ella) included evaluation of accuracy (bias), intra/inter-assay precision, analytical range, parallelism, selectivity, and stability. Accuracy and precision was assessed with spiked and endogenous quality controls (QCs) at multiple levels to reflect the range of expected values in MS patients. MS serum was used to assess NfL and NfH stability and evaluate parallelism, informing dilution requirements, selectivity, and endogenous analyte assay sensitivity.
Results: The analytical ranges for both NfL and NfH assays were appropriate for the expected values in MS patients. Serum NfH assay sensitivity was determined to be 7.5 pg/mL, accuracy and precision met the performance criteria, and serum NfH was stable under all conditions tested, including multiple freeze-thaw cycles. Serum NfL assay sensitivity was determined to be 0.7 pg/mL and serum NfL was stable under all conditions tested. While the Simoa NfL assay demonstrated reproducible calibrator performance, two key observations impacted the accuracy and precision of NfL measurements: (1) inter-assay bias in spiked QC preparation and (2) a position-effect bias for endogenous and spiked QCs. To mitigate these effects, QCs for batch acceptance were prepared in bulk and calibrators and samples were strategically placed to distribute the position-effect bias.
Conclusions: While the NfH assay met the necessary performance requirements, the NfL assay required mitigation strategies to manage analytical issues that could have profound impact on clinical data analyses.
Supported by: Biogen.
Disclosure: Ankur Sharma: employee of Biogen and holds stock/stock options in Biogen
Marco Petrillo: employee of Biogen and holds stock/stock options in Biogen
Guolin Zhao: employee of Biogen and holds stock/stock options in Biogen
Jake Gagnon: employee of Biogen and holds stock/stock options in Biogen
Tatiana Plavina: employee of Biogen and holds stock/stock options in Biogen
Carol Singh: employee of Biogen and holds stock/stock options in Biogen
Ray Su: employee of Biogen and holds stock/stock options in Biogen
Chris Stebbins: employee of Biogen and holds stock/stock options in Biogen
Lauren Stevenson: employee of Biogen and holds stock/stock options in Biogen
Devangi Mehta: employee of Biogen and holds stock/stock options in Biogen