Combined Chemotherapy and Subcutaneous Administration of Macrophage-like Monocyte-Derived Exosomes Carrying Tumor Antigens in a Female Dog with CTVT

Background: Canine Transmissible Venereal Tumor (CTVT) is a contagious round-cell tumor primarily transmitted through mating or direct physical contact. It affects the genital mucosa and occasionally extragenital sites. Common treatments include surgery, chemotherapy, and immunotherapy. Surgery often results in recurrence, while vincristine-based chemotherapy has proven effective. This case study investigated whether combining vincristine chemotherapy with subcutaneous immunotherapy using macrophage-like monocyte–derived exosomes carrying CTVT tumor antigens could enhance therapeutic efficacy and clinical recovery. Methods: A six-year-old, ۲۰ kg female mixed-breed dog (Jessie, Iranian native × Shih Tzu) presented with severe cachexia and a ۱۳ × ۲۰ cm genital mass at the University of Tehran Veterinary Hospital (April ۱۶, ۲۰۲۴). CTVT was confirmed by cytology and histopathology. Baseline imaging and hematology showed no metastasis. The dog received six weekly doses of vincristine combined with ondansetron, along with three subcutaneous injections of macrophage-like monocyte–derived exosomes carrying CTVT tumor antigens. Exosomes were produced by incubating patient-derived monocytes with tumor lysate for ۲۴ hours, then isolated, characterized, and quantified using TEM, DLS/Zeta, and NanoDrop analyses. Nutritional support was provided during hospitalization, and full laboratory re-evaluation was performed after six weeks. Results: Combined therapy produced marked tumor necrosis and volume reduction from ۱۳ × ۲۰ cm to approximately ۴ × ۶ cm. The patient gained ۱۰ kg, showed improved condition, and had no signs of systemic or local toxicity based on hematological, biochemical, radiological, or ultrasonographic parameters. Conclusion: The concurrent use of vincristine chemotherapy and subcutaneous administration of macrophage-like monocyte–derived exosomes carrying tumor antigens led to significant tumor regression and clinical improvement without adverse effects. This therapeutic synergy highlights the potential of exosome-based immunotherapy as an effective adjunct to chemotherapy in treating CTVT.

کلیدواژه ها:

Canine Transmissible Venereal Tumor (CTVT) ، Immunotherapy ، Exosomes ، Chemotherapy ، Tumor antigen delivery