Cytokine-Enhanced Vaccine and Interferon-β plus Suicide Gene Therapy as Surgery Adjuvant Treatments for Spontaneous Canine Melanoma

Abstract

We present here a nonviral immunogene therapy trial for canine malignant melanoma, an aggressive disease displaying significant clinical and histopathological overlapping with human melanoma. As a surgery adjuvant approach, it comprised the co-injection of lipoplexes bearing herpes simplex virus thymidine kinase and canine interferon-b genes at the time of surgery, combined with the periodic administration of a subcutaneous genetic vaccine composed of tumor extracts and lipoplexes carrying the genes of human interleukin-2 and human granulocyte-macrophage colony-stimulating factor. Following complete surgery (CS), the combined treatment (CT) significantly raised the portion of local disease-free canine patients from 11% to 83% and distant metastases-free (M0) from 44% to 89%, as compared with surgery-only-treated controls (ST). Even after partial surgery (PS), CT better controlled the systemic disease (M0: 82%) than ST (M0: 48%). Moreover, compared with ST, CT caused a significant 7-fold (CS) and 4-fold (PS) rise of overall survival, and > 17-fold (CS) and > 13-fold (PS) rise of metastasis-free survival. The dramatic increase of PS metastasis-free survival ( > 1321 days) and CS recurrence-and metastasis-free survival (both > 2251 days) demonstrated that CT was shifting a rapidly lethal disease into a chronic one. In conclusion, this surgery adjuvant CT was able of significantly delaying or preventing postsurgical recurrence and distant metastasis, increasing disease-free and overall survival, and maintaining the quality of life. The high number of canine patients involved in CT (301) and the extensive follow-up ( > 6 years) with minimal or absent toxicity warrant the long-term safety and efficacy of this treatment. This successful clinical outcome justifies attempting a similar scheme for human melanoma.

Prolongation of survival of dogs with oral malignant melanoma treated byen blocsurgical resection and adjuvantCSPG4‐antigen electrovaccination

“…As the role of adjuvant chemotherapy in prolonging survival of dogs bearing an oral cMM and controlling/delaying of the distant metastatic spread is uncertain, many studies have been addressed to alternative adjuvant treatments, such as new drugs and immunotherapy, also in form of combined protocols…”

“…Local control of cMM relies mainly on surgery and/or radiotherapy; adjuvant chemotherapy has been used in an attempt to control the systemic spread . Due to the often disappointing results obtained with standard chemotherapy and also to the high immunogenicity of MM, immunotherapy is progressively becoming one of the most attractive adjunctive therapeutic tools, also in the form of combined protocols . Other treatments reported in the literature include the use of lupeol …”

Intratumoural interleukin 12 gene therapy stimulates the immune system and decreases angiogenesis in dogs with spontaneous cancer

“…As an alternative, the efficacy of IL‐12 therapy could be enhanced by combining it with metronomic cyclophosphamide to selectively decrease the amount of Tregs, as IL‐12 effects are transient and induce a rebound in Tregs . Furthermore, immunotherapy generally has a more powerful effect in a minimal residual disease setting, thus, IL‐12 therapy could benefit from a combinatorial strategy with surgery or electrochemotherapy …”

Clinical Trials of Immunogene Therapy for Spontaneous Tumors in Companion Animals

“…To overcome the limitations imposed by the costly production and delivery of cytokine producing transgenic xenogeneic cells as well as the appearance of canine melanoma resistant to suicide gene therapy, we designed a new trial where these cells were replaced by lipoplexes carrying the corresponding cytokines genes in the subcutaneous vaccine and canine interferon- β (cIFN- β ) strengthened the local antitumor effects [ 31 ]. After 6 years of follow-up, 301 canine patients were subjected to the combined treatment as surgery adjuvant and 162 remained as surgery controls.…”