New Approach for GMP-Compliant Testing of MOA of Therapeutic Antibodies Offers Considerable Advantages

Aug 03 2012

One important mode of action (MOA) of many receptor-binding therapeutic antibodies is antibody-dependent cellular cytotoxicity (ADCC). According to various authorities’ requirements, in vitro potency tests should reflect the MOA of the therapeutic antibody. Classical ADCC setups are tedious and time-consuming and pose a challenge for any GMP-compliant method validation, which is a prerequisite for lot release testing.

Charles River has introduced and validated an entirely new approach for potency testing of the therapeutic antibody rituximab. This new ADCC approach is based on a luminescence readout and the use of genetically engineered reporter cells provided by Promega. These engineered reporter cells substitute for the primary effector cells because the same signaling pathway is activated if FcgRIIIa binds to the target cell-bound antibody. This induces the NFAT-RE-luc reporter construct of the effector cell, resulting in a chemiluminescence signal. In general, luminescence-based readout and the use of genetically engineered reporter cells is a trend in the bioanalytics field.

This new approach has several advantages compared to the classical ADCC approach including:

  • Highly sensitive, dose-dependent activity in the ng/ml range

  • Works well over a range of 50% to 150% estimated potency of the test item

  • Validation according to ICH Q2(R1) possible

  • Excellent  reproducibility

  • Less expensive and time-consuming than ADCC assays with primary effector cells

  • Good signal-to-noise ratio

  • Extremely low background

  • Several samples can be tested in parallel

The new approach complements GMP-compliant applications such as release and stability testing and can be used as an indicator that reflects potency differences between biosimilars and biobetters. Additionally, this new approach can easily be transferred to other therapeutic antibody target cell combinations.

To learn more about this new ADCC approach, please contact us at askcharlesriver@crl.com.

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