Development of a Humanized VHH Based Recombinant Antibody Targeting Claudin 18.2 Positive Cancers

Area of Science:

• Oncology
• Immunology
• Biotechnology

Background:

• Claudin 18.2 (CLDN18.2) is over-expressed in gastric and pancreatic cancers, making it a promising therapeutic target.
• Current therapeutic strategies targeting CLDN18.2 include monoclonal antibodies.
• Developing novel therapeutic agents with improved efficacy and targeting capabilities is crucial.

Purpose of the Study:

• To develop novel anti-CLDN18.2 therapeutic candidates using variable domain of heavy chain of heavy chain antibodies (VHHs).
• To evaluate the efficacy and tumor-targeting properties of these VHH-based candidates.
• To compare the performance of the developed VHH-Fc fusion protein against Zolbetuximab.

Main Methods:

• Isolation of CLDN18.2-specific VHHs from an alpaca-immunized phage display library.
• Humanization and Fc-fusion of VHHs to create therapeutic candidates (hu7v3-Fc).
• In vitro cytotoxicity assays (ADCC, CDC) and in vivo studies using mouse xenograft models and 89Zr-labeled antibodies for biodistribution.

Main Results:

• Humanized VHH-Fc fusion proteins demonstrated high specificity and affinity for CLDN18.2.
• hu7v3-Fc induced both antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) in CLDN18.2-positive tumor cells.
• In vivo, hu7v3-Fc showed superior anti-tumor efficacy, faster tumor uptake, and better tumor penetration than Zolbetuximab.

Conclusions:

• Anti-CLDN18.2 hu7v3-Fc is a potent therapeutic candidate for CLDN18.2-positive cancers.
• The VHH-based approach offers advantages in terms of size, affinity, and efficacy.
• hu7v3 represents a promising platform for developing novel CLDN18.2-targeted therapeutics.