(T1330-01-02) Screening and Epitope Binning of Anti-idiotypic Antibodies against Therapeutic Bispecific Antibodies Using the Gyros Immunoassay Platform

Tuesday, April 25, 2023

1:30 PM – 2:30 PM ET

Presenting Author(s)

YC

Yury Chaly, Ph.D.

Senior Principal Scientist
Bristol-Myers Squibb Company
Princeton, New Jersey, United States

Main Author(s)

YC

Yury Chaly, Ph.D.

Senior Principal Scientist
Bristol-Myers Squibb Company
Princeton, New Jersey, United States

Co-Author(s)

VJ

Vibha Jawa, Ph.D.

Executive Director
Bristol-Myers Squibb Company
Princeton, New Jersey, United States
AK

Alexander Kozhich, Ph.D.

Scientific Director
Bristol-Myers Squibb Company
Princeton, New Jersey, United States

Purpose: Anti-idiotypic (anti-ID) antibodies (Abs) are widely used in the development of biopharmaceuticals. Anti-ID Abs are the powerful tool reagents for pharmacokinetic (PK) and anti-drug antibody (ADA) assays. The aim of the current work was to characterize anti-ID Abs against a therapeutic bispecific antibody (BsAb) at the micropurification stage and select best reagents for ligand binding assays in human matrix.

Methods: To develop a suite of screening methods, we made use of of the Gyros microfluidic immunoassay platform. The methods are based on using species-specific capture antibodies for anti-IDs Abs. Antigens (full BsAb, arm A or arm B) labeled with AlexaFluor 647 were used for detection in Rexxip F buffer containing 10% human serum. The methods utilized 3-step-2-wash Wizard protocol with Gyrolab Bioaffy 200 CD.

Results: The developed assays were used to screen 39 samples of purified anti-ID Abs using either single or a panel of related antigens. Antigen/Ab binding was evaluated in the presence of human serum. The signal-to-noise (S/N) of the responses was calculated by dividing the raw mean fluorescence signal from the sample by the mean signal derived from the negative control. The range of S/N values observed in our experiments was from 1 to 500, sufficient to enable discrimination of binding of anti-ID Abs to corresponding antigens. 11 anti-ID Abs targeting either the arm A or the arm B of the BsAb were identified (table).

Conclusion: Using the Gyros platform, we successfully characterized 39 anti-ID Abs against the therapeutic BsAb. 11 anti-ID Abs were selected for scaling up, identifying blockers/non-blockers as well as potential pairs for ligand binding assays.