Response to oncolytic virus in canine patients with spontaneous gliomas

P Delgado-Bonet(1) B D Tomeo-Martín(1) F del Ry(3) I Mateo Pampliega(3) J García-Castro(2) A J Perisé-Barrios(1)

1:Universidad Alfonso X El Sabio; 2:Instituto de Salud Carlos III; 3:Hospital Clínico Veterinario - UAX

Gliomas are the most frequent malignant intracranial tumors in dogs, presenting a poor therapeutic response to the treatments. The use of oncolytic adenovirus to treat gliomas has shown promising results in murine models and human clinical trials. Due to the poor prognosis of canine patients with gliomas, we propose using oncolytic adenovirus ICOCAV15 to improve their well-being and survival.

The ICOCAV15 will produce a lysis of tumor cells, and will activate immune response, thereby reducing tumor burgeon in patients with gliomas.

Eight companion dogs with spontaneous gliomas diagnosed by the Neurology Department at the UAX Veterinary Hospital were included.

Surgery by craniotomy, a biopsy of the tumor was taken for diagnosis. ICOCAV15 was intratumorally administered in 6 dogs. Routine blood analysis was performed during follow-up. Tumor samples (pretreatment and post-mortem) were obtained to detect CD3, IBA1 and Calprotectin by immunohistochemistry. Follow-up by MRI to determine RAVNO criteria. This study was approved by the Ethics Evaluation Committee of the Official College of Veterinarians of Madrid (COLVEMA).

ICOCAV15 manage 2/6 CR (6 and 13 months) and 2/6 SD (6 and 27 months). Median survival time was 247 days in treated patients (n=6, two remain alive), and 76 days in the control group (n=2, one remains alive). An increase of CD3, IBA1 and Calprotectin was observed in ICOCAV15-treated tumors.

This proof of concept shows a longer survival time, higher immune infiltration, and absence of secondary effects in intracranial ICOCAV15-treated patients; therefore, ICOCAV15 should be further explored as a treatment in veterinary neuro-oncology.