Institute for International Research

Tuesday, May 8, 2007: PRE-CONFERENCE FULL DAY SYMPOSIUM B1
Platforms and Technologies for Anti-Drug Antibody Assays

Compare ECLA and ELISA Technologies to Determine the Best Platform for your Applications: Electrochemiluminescence 3 Years Later: 6 Separate Head-to-Head Studies

8:30 Workshop Registration
9:00 Workshop Opens
10:30 30-Minute Networking Break
12:00 Luncheon for morning workshop presenters and delegates

Case study # 8-11

This workshop covers several techniques that are important for addressing a wide range of technical and scientific challenges associated with the qualitative and quantitative evaluation of neutralizing antibodies (Nab). One factor that affects Nab assay results is the small magnitude of the response associated with typically low positive specimens compared to the high variance (noise) of negative specimens. This low signal-to-noise ratio makes the assay cutpoint determination a difficult task. Another factor is the heterogeneity of the antibodies generated in positive patients in response to drug treatment. This heterogeneity makes quantitative assays difficult to interpret, due to non-parallel curves obtained with a positive patient specimen and positive nonhuman Nab. These and other factors, such as matrix variability from specimen to specimen, require appropriate statistical consideration to decrease the rate of false positives and false negatives.

Topics covered include:

• Incorporating the intra-assay variance into the cutpoint of qualitative and quantitative Nab assays.
  
• Determining a reliable limit of detection (LOD) as a consideration of cutpoint thresholds.
  
• Determining limits of quantitation (LOQ) of positive specimens and evaluating them as a positive threshold in conjunction with cutpoint thresholds determined from negative specimens.
  
• Compensating for matrix differences between specimens and other factors that affect the assay performance.

Workshop Leader:
John R. Dunn, PhD, Chief Technical Officer
BRENDAN TECHNOLOGIES

12:30 Workshop Registration
1:30 Workshop Opens
3:00 30-Minute Networking Break
5:00 Workshop Concludes
5:00-6:30 Please join us for reception hosted by Meso Scale Discovery

Matrix interference could be defined as substance(s) in serum/plasma that can through their interaction with assay component affect, either positively or negatively, the signal generated in an assay, such that results produced could be inaccurate. Reactivity of many of the substances that that cause matrix interference are specific, though irrelevant to the product being tested.

Examples of matrix interference may include:

• Reactivity of serum/plasma components (IgG/IgM) with carbohydrates of analyte
  
• Reactivity of serum/plasma component with the analyte (soluble receptor, binding protein, anti-cytokine Abs) as a result of normal physiological response
  
• Reactivity of serum/plasma component (IgG/IgM) with "impurities" in the product

Matrix interference can be reduced by simple solutions, e.g. increasing dilution factor or ionic strength. Such solutions, however, may reduce sensitivity of the assay and may not completely reduce interference in samples from some individuals. Identifying the source of the interference may allow its removal and the development of more sensitive assays that works with all individuals.

These and other issues as well as solutions or methods to solve these issues will be discussed.

Workshop leader:
Michel Awwad, PhD, Associate Director, DSM
WYETH