Monoclonal antibodies (mAbs) are poised to revolutionize the treatment of cancer in companion animals, offering highly specific therapeutic options that minimize the severe side effects often associated with traditional chemotherapy and radiation therapy. The application of mAbs in veterinary oncology, which is currently an emerging but high-value segment, represents a significant shift towards personalized and targeted medicine, and the potential of this market to grow significantly over the next decade is underscored by recent approvals and pipeline developments, which are detailed further in specialized reports such as the one found here: Monoclonal Antibodies in Veterinary Oncology.

1. Mechanisms of Action in Veterinary Cancer

Veterinary mAbs for cancer largely mirror the strategies used in human oncology but are engineered to be species-specific (caninized/felinized) to ensure efficacy and reduce immunogenicity. The primary mechanisms include:

• Immune Checkpoint Inhibition: The most prominent strategy is the use of mAbs that block inhibitory signals (checkpoints) on T-cells, such as the anti-PD-1 mAb Gilvetmab (conditionally approved for mast cell tumors and melanomas in dogs). By blocking the PD-1 signal, the mAb "unleashes" the dog's immune system to recognize and destroy the cancer cells.

• Naked Monoclonal Antibodies: These bind directly to antigens (proteins) overexpressed on the surface of tumor cells, acting alone to flag the cancer cell for destruction by the animal's natural immune system (Antibody-Dependent Cell-mediated Cytotoxicity, or ADCC).

• Antibody-Drug Conjugates (ADCs): The future of this field involves conjugated mAbs, which bind to a tumor-specific antigen and carry a cytotoxic payload (a chemotherapy drug or radioactive particle) directly to the cancer cell, limiting systemic toxicity to healthy tissues.

2. Species and Target Focus

While cancer occurs in all animals, R&D is primarily focused on canine oncology due to the high incidence of certain tumor types and the high expenditure on canine health: