The promise of immunotherapeutic strategies to advance cancer treatment in pet dogs.

In this article, which is part of the Currents in One Health series, principles of immunotherapeutics are discussed and their clinical exploration in dogs reviewed with emphasis on their translatability for improving treatment of commonly diagnosed cancers. With increasing longevity and sustained quality of life in pet dogs through dietary, environmental awareness, and preventative medical practices, the geriatric pet population has continued to steadily grow and, consequently, so have age-related pathologies. Not surprisingly, cancer is the most common cause of mortality in elderly dogs, accounting for 1 in 4 deaths in dogs > 10 years of age. Importantly, some cancer types that arise spontaneously in pet dogs are similar to cancers afflicting people. The shared clinical and biological behaviors of certain cancers observed in pet dogs and people underscore the opportunity to leverage comparative oncology studies, which can accelerate the validation and clinical implementation of innovative therapies that can benefit pet dogs and ultimately guide these strategies toward clinical practice in people too. In the era of immunotherapy, the inclusion of pet dogs that develop cancers under an intact immune system affords a unique and high-value opportunity to study the evolving nature of cancers shaped by immunosurveillance pressures. Complementing these discovery efforts and through a comparative oncology approach, the exploration and clinical validation of novel immunotherapeutic strategies in pet dogs can be foundational for defining the safety and immune-activating potential of new anticancer immune approaches that hold promise to transform cancer treatment in both pets and people alike.