Oncolytic Sendai Virus Therapy of Canine Mast Cell Tumors (A Pilot Study)

Abstract

Background: Canine mastocytomas (mast cell tumors) represent a common malignancy among many dog breeds. A typical treatment strategy for canine mastocytomas includes surgery, chemo- and radio-therapy, although in many cases the therapy fails and the disease progression resumes. New treatment approaches are needed.Aims: The goal of this pilot study was to examine safety and efficacy of oncolytic Sendai virus therapy administered to canine patients with cutaneous or subcutaneous mastocytomas.Materials and Methods: Six canine patients, with variable grades and stages of the disease, received virus therapy, either as a monotherapy, or in combination with surgery. The therapy included two or more virus applications administered weekly or biweekly. Each application of Sendai virus (107-108.6 EID50) consisted of multiple individual 0.01–0.1 ml injections delivered intratumorally, intradermally around a tumor, and under a tumor bed.Results: The treatment was well tolerated, with minor transitory side effects. Of the six dogs, two did not receive surgery or any other treatment besides the virus injections. The other four animals underwent radical or debulking surgeries, and in three of them the subsequent administration of Sendai virus completely cleared locally recurrent or/and remaining tumor masses. Five dogs demonstrated a complete response to the treatment, the animals remained disease free during the time of observation (2–3 years). One dog responded only partially to the virotherapy; its after-surgical recurrent tumor and some, but not all, metastases were cleared. This dog had the most advanced stage of the disease with multiple enlarged lymph nodes and cutaneous metastases.Conclusion: The results of the pilot study suggest that Sendai virus injections could be safe and efficient for the treatment of dogs affected by mastocytomas.They also suggest the need of further studies for finding optimal schemes and schedules for this kind of therapy.

Oncolytic Viruses for Canine Cancer Treatment

“…Four dogs with either primary or recurrent tumors achieved complete responses, three of them long-lasting. The remaining two achieved stable disease [ 79 ]. These results justify further clinical studies of SV for the treatment of canine cutaneous/subcutaneous mastocytoma.…”

“…These results justify further clinical studies of SV for the treatment of canine cutaneous/subcutaneous mastocytoma. Small lesions showed a better response to SV therapy [ 79 ]; yet, in routine practice, these lesions are usually resected. [ 80 ].…”

“…It would be interesting to test the use of this virus in an adjuvant or neo-adjuvant setting for mastocytoma, in order to determine whether the virus is able to control residual disease or reduce tumor burden facilitating surgery. It also will be important to evaluate drug interactions, especially when combined with steroids, which could decrease its therapeutic efficacy [ 79 ]. Following a pathological exam, SV was shown to induce infiltration by dendritic cells, CD4 and CD8 T-cells, and natural killer (NK) cells [ 77 , 81 ].…”

Safety studies and viral shedding of intramuscular administration of oncolytic vaccinia virus TG6002 in healthy beagle dogs

“…Oncolytic viruses are gaining ground as an alternative therapy in veterinary oncology. Several studies involving adenovirus, myxoma virus, Sendai virus, reovirus and vesicular stomatitis virus have been conducted in dogs and cats [28][29][30][31][32][33][34][35][36]. Promising results have been reported by intratumoral or intravenous routes on dogs and cats with cancer.…”

Safety studies and viral shedding of intramuscular administration of oncolytic vaccinia virus TG6002 in healthy Beagle dogs

“…Oncolytic viruses are gaining ground as an alternative therapy for treating cancer in veterinary oncology. Indeed, several studies involving adenovirus, myxoma virus, sendai virus, reovirus and vesicular stomatitis virus have been conducted in dogs and cats [28][29][30][31][32][33][34][35][36]. Promising results have been reported by intratumoral or intravenous routes on dogs and cats bearing cancers.…”