Intratumoral (Poly-ICLC) Therapy for Dogs with Advanced Cancers: First Report on Clinical Effectiveness, Quality of Life, and Adverse Events

SIMPLE SUMMARY: Although polyinosinic-polycytidylic acid-poly-l-lysine carboxymethylcellulose (poly-ICLC) is widely used as a standalone agent for treating human cancers, there are no reports on its use for treating canine cancers. We aimed to investigate the clinical efficacy, quality of life, and adverse events of poly-ICLC treatment in dogs with advanced cancers. Our results showed that intratumoral poly-ICLC therapy was well tolerated in dogs with advanced cancers, with clinical benefit and improved quality of life scores observed in some dogs. Our findings suggested that patients with lower tumor burden may benefit more from this treatment. ABSTRACT: Polyinosinic-polycytidylic acid-poly-l-lysine carboxymethylcellulose (poly-ICLC) is a synthetic double-stranded viral RNA analog widely tested as a component of human therapeutic cancer vaccines and as a standalone agent for treating human cancers. However, there are no reports on the use of poly-ICLC for treating canine cancers. This study aimed to investigate the clinical efficacy, quality of life (QL), and adverse events of poly-ICLC treatment in dogs with advanced cancers. The treatment protocol consisted of weekly intratumoral doses of poly-ICLC. The canine patients underwent clinical, laboratory, and imaging tests, and their owners answered weekly QL questionnaires. Fourteen canine patients with different types of spontaneous advanced tumors were enrolled. Most dogs had received prior conventional therapies. Five dogs received at least 12 doses of poly-ICLC: the injected tumor was stable in three dogs, there was a partial response in one, and the injected tumor significantly enlarged in the other. The QL scoring remained stable or increased in most cases. Mild adverse events related to poly-ICLC were observed in 10 of the 14 patients. The data showed that intratumoral poly-ICLC therapy was well tolerated in dogs with advanced cancers, with clinical benefit and improved QL scores observed in some dogs.