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Published on: November 18, 2014
The emergence of cell-based protein arrays to test for polyspecific off-target binding of antibody therapeutics
Diana M Norden1, Carmen T Navia1, Jonathan T Sullivan1
1Integral Molecular, Philadelphia, PA, USA.
Abstract:
Specificity profiling is a requirement for monoclonal antibodies (mAbs) and antibody-directed biotherapeutics such as CAR-T cells prior to initiating human trials. However, traditional approaches to assess the specificity of mAbs, primarily tissue cross-reactivity studies, have been unreliable, leading to off-target binding going undetected. Here, we review the emergence of cell-based protein arrays as an alternative and improved assessment of mAb specificity. Cell-based protein arrays assess binding across the full human membrane proteome, ~6,000 membrane proteins each individually expressed in their native structural configuration within live or unfixed cells. Our own profiling indicates a surprisingly high off-target rate across the industry, with 33% of lead candidates displaying off-target binding. Moreover, about 20% of therapeutic mAbs in clinical development and currently on the market display off-target binding. Case studies and off-target rates at different phases of biotherapeutic drug approval suggest that off-target binding is likely a major cause of adverse events and drug attrition.
Insights
Cell-based protein arrays offer a more reliable method for assessing monoclonal antibody (mAb) specificity compared to traditional tissue cross-reactivity studies. This improved specificity profiling can reduce off-target binding, potentially preventing adverse events in biotherapeutic development.
Area of Science:
- Biochemistry
- Immunology
- Drug Development
Background:
- Specificity profiling is crucial for monoclonal antibodies (mAbs) and CAR-T cells before human trials.
- Traditional tissue cross-reactivity studies for mAb specificity are unreliable, often missing off-target binding.
- Off-target binding can lead to undetected issues in biotherapeutic development.
Purpose of the Study:
- To review cell-based protein arrays as an improved method for assessing mAb specificity.
- To highlight the limitations of traditional specificity assessment methods.
- To present data on the prevalence of off-target binding in therapeutic antibodies.
Main Methods:
- Review of cell-based protein array technology for specificity assessment.
- Analysis of binding across the full human membrane proteome (~6,000 proteins).
- Expression of membrane proteins in native configuration within live or unfixed cells.
Main Results:
- Cell-based protein arrays provide a comprehensive assessment of mAb specificity.
- A high rate of off-target binding was observed: 33% in lead candidates and 20% in marketed therapeutic mAbs.
- Off-target binding is implicated as a significant cause of adverse events and drug attrition.
Conclusions:
- Cell-based protein arrays represent a superior alternative for mAb specificity profiling.
- Addressing off-target binding early in development is critical for biotherapeutic safety and success.
- Improved specificity assessment can mitigate risks associated with therapeutic antibodies.
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