Clinical Trials of Cancer Immunogene Therapies in Companion Animals: An Update (2017-2024)

This review summarizes the findings of veterinary clinical trials on immunogene therapy published between 2017 and 2024. Various tumor types, including melanoma (canine and feline), mastocytoma (canine), mammary adenocarcinoma (canine), osteosarcoma (canine), and sarcoid (equine), were treated using diverse strategies. Non-viral vectors were predominantly used to deliver genes encoding tumor-associated antigens, cytokines, or suicide enzymes. Among these non-viral methods, electrotransfer was the most commonly employed technique for introducing therapeutic genes into cells. Generally, these procedures resulted in minimal or no adverse side effects, and treated animals often showed significant improvements, such as enhanced quality of life, delayed or suppressed tumor recurrence or metastasis, and increased survival times. Some of these innovative approaches hold great potential as adjunct therapies to standard treatments. The promising outcomes from immunogene therapy studies in companion animals strongly support their application in veterinary oncology and provide valuable preclinical data (including safety assessments and proof-of-concept studies) for analogous human clinical trials.