A pRb-responsive, RGD-modified, and hyaluronidase-armed canine oncolytic adenovirus for application in veterinary oncology

Human and canine cancer share similarities such as genetic and molecular aspects, biological complexity, tumor epidemiology, and targeted therapeutic treatment. Lack of good animal models for human adenovirotherapy has spurred the use of canine adenovirus 2-based oncolytic viruses. We have constructed a canine oncolytic virus that mimics the characteristics of our previously published human adenovirus ICOVIR17: expression of E1a controlled by E2F sites, deletion of the pRb-binding site of E1a, insertion of an RGD integrin-binding motif at the fiber Knob, and expression of hyaluronidase under the major late promoter/IIIa protein splicing acceptor control. Preclinical studies showed selectivity, increased cytotoxicity, and strong hyaluronidase activity. Intratumoral treatment of canine osteosarcoma and melanoma xenografts in mice resulted in inhibition of tumor growth and prolonged survival. Moreover, we treated six dogs with different tumor types, including one adenoma, two osteosarcomas, one mastocitoma, one fibrosarcoma, and one neuroendocrine hepatic carcinoma. No virusassociated adverse effects were observed, but toxicity associated to tumor lysis, including disseminated intravascular coagulation and systemic failure, was found in one case. Two partial responses and two stable diseases warrant additional clinical testing

Osteosarcoma cells as carriers to allow antitumor activity of canine oncolytic adenovirus in the presence of neutralizing antibodies

Osteosarcoma (OSA) is the most common bone tumor affecting the dog. The veterinary options for therapeutic management of OSA are limited and prognosis for such patients is poor. Oncolytic adenoviruses are attractive tools for experimental therapeutics as they can replicate and spread within tumors to directly induce tumor destruction. However, a major impediment to systemic oncolytic adenoviruses injection is the presence of pre-existing neutralizing antibodies (Nabs). In this study, we investigated the effect of a replication-selective canine adenovirus (OCCAV) to treat OSA in the presence of Nabs and the use of canine OSA cells as carrier vehicles for evading Nabs. Our systemic biodistribution data indicated that canine tumor cells could successfully reach the tumor site and deliver OCCAV to tumor cells in an immunized mice model. Furthermore, the use of carrier cells also reduced adenovirus uptake by the liver. Importantly, OCCAV alone was not effective to control tumor growth in a pre-immunized xenograft mouse model. On the contrary, systemic antitumoral activity of carrier-cell OCCAV was evident even in the presence of circulating antibodies, which is a relevant result from a clinical point of view. These findings are of direct translational relevance for the future design of canine clinical trials

Hyaluronidase expression by an oncolytic adenovirus enhances its intratumoral spread and supresses tumor growth

Successful virotherapy requires efficient virus spread within tumors. We tested whether the expression of hyaluronidase, an enzyme which dissociates the extra-cellular matrix (ECM), could enhance the intratumoral distribution of an oncolytic adenovirus and improve its therapeutic activity. As a proof of concept, we demon-strated that intratumoral coadministration of hyaluroni-dase in mice-bearing tumor xenografts improves the antitumor activity of an oncolytic adenovirus. Next, we constructed a replication-competent adenovirus express-ing a soluble form of the human sperm hyaluronidase (PH20) under the control of the major late promoter (MLP) (AdwtRGD-PH20). Intratumoral treatment of human melanoma xenografts with AdwtRGD-PH20 resulted in degradation of hyaluronan (HA), enhanced viral distribution, and induced tumor regression in all treated tumors. Finally, the PH20 cDNA was inserted in an oncolytic adenovirus that selectively kills pRb pathway-defective tumor cells. The antitumoral activ-ity of the novel oncolytic adenovirus expressing PH20 (ICOVIR17) was compared to that of the parental virus ICOVIR15. ICOVIR17 showed more antitumor efficacy following intratumoral and systemic administration in mice with prestablished tumors, along with an improved spread of the virus within the tumor. Importantly, a single intravenous dose of ICOVIR17 induced tumor regression in 60% of treated tumors. These results indicate that ICOVIR17 is a promising candidate for clinical testing

A pRb-responsive, RGD-modified, and hyaluronidase-armed canine oncolytic adenovirus for application in veterinary oncology

Human and canine cancer share similarities such as genetic and molecular aspects, biological complexity, tumor epidemiology, and targeted therapeutic treatment. Lack of good animal models for human adenovirotherapy has spurred the use of canine adenovirus 2-based oncolytic viruses. We have constructed a canine oncolytic virus that mimics the characteristics of our previously published human adenovirus ICOVIR17: expression of E1a controlled by E2F sites, deletion of the pRb-binding site of E1a, insertion of an RGD integrin-binding motif at the fiber Knob, and expression of hyaluronidase under the major late promoter/IIIa protein splicing acceptor control. Preclinical studies showed selectivity, increased cytotoxicity, and strong hyaluronidase activity. Intratumoral treatment of canine osteosarcoma and melanoma xenografts in mice resulted in inhibition of tumor growth and prolonged survival. Moreover, we treated six dogs with different tumor types, including one adenoma, two osteosarcomas, one mastocitoma, one fibrosarcoma, and one neuroendocrine hepatic carcinoma. No virusassociated adverse effects were observed, but toxicity associated to tumor lysis, including disseminated intravascular coagulation and systemic failure, was found in one case. Two partial responses and two stable diseases warrant additional clinical testing

A pRb-responsive, RGD-modified, and Hyaluronidase-armed Canine Oncolytic Adenovirus for Application in Veterinary Oncology

Human and canine cancer share similarities such as genetic and molecular aspects, biological complexity, tumor epidemiology, and targeted therapeutic treatment. Lack of good animal models for human adenovirotherapy has spurred the use of canine adenovirus 2-based oncolytic viruses. We have constructed a canine oncolytic virus that mimics the characteristics of our previously published human adenovirus ICOVIR17: expression of E1a controlled by E2F sites, deletion of the pRb-binding site of E1a, insertion of an RGD integrin-binding motif at the fiber Knob, and expression of hyaluronidase under the major late promoter/IIIa protein splicing acceptor control. Preclinical studies showed selectivity, increased cytotoxicity, and strong hyaluronidase activity. Intratumoral treatment of canine osteosarcoma and melanoma xenografts in mice resulted in inhibition of tumor growth and prolonged survival. Moreover, we treated six dogs with different tumor types, including one adenoma, two osteosarcomas, one mastocitoma, one fibrosarcoma, and one neuroendocrine hepatic carcinoma. No virus-associated adverse effects were observed, but toxicity associated to tumor lysis, including disseminated intravascular coagulation and systemic failure, was found in one case. Two partial responses and two stable diseases warrant additional clinical testing

Therapeutic targeting of the RB1 pathway in retinoblastoma with the oncolytic adenovirus VCN-01

Retinoblastoma is a pediatric solid tumor of the retina activated upon homozygous inactivation of the tumor suppressor RB1. VCN-01 is an oncolytic adenovirus designed to replicate selectively in tumor cells with high abundance of free E2F-1, a consequence of a dysfunctional RB1 pathway. Thus, we reasoned that VCN-01 could provide targeted therapeutic activity against even chemoresistant retinoblastoma. In vitro, VCN-01 effectively killed patient-derived retinoblastoma models. In mice, intravitreous administration of VCN-01 in retinoblastoma xenografts induced tumor necrosis, improved ocular survival compared with standard-of-care chemotherapy, and prevented micrometastatic dissemination into the brain. In juvenile immunocompetent rabbits, VCN-01 did not replicate in retinas, induced minor local side effects, and only leaked slightly and for a short time into the blood. Initial phase 1 data in patients showed the feasibility of the administration of intravitreous VCN-01 and resulted in antitumor activity in retinoblastoma vitreous seeds and evidence of viral replication markers in tumor cells. The treatment caused local vitreous inflammation but no systemic complications. Thus, oncolytic adenoviruses targeting RB1 might provide a tumor-selective and chemotherapy-independent treatment option for retinoblastoma.Fil: Pascual-Pasto, Guillem. Hospital Sant Joan de Déu; EspañaFil: Bazan-Peregrino, Miriam. No especifíca;Fil: Olaciregui, Nagore G.. Hospital Sant Joan de Déu; EspañaFil: Restrepo Perdomo, Camilo A.. Hospital Sant Joan de Déu; EspañaFil: Mato Berciano, Ana. No especifíca;Fil: Ottaviani, Daniela. Centre National de la Recherche Scientifique; FranciaFil: Weber, Klaus. No especifíca;Fil: Correa, Genoveva. Hospital Sant Joan de Déu; EspañaFil: Paco, Sonia. Hospital Sant Joan de Déu; EspañaFil: Vila Ubach, Monica. Hospital Sant Joan de Déu; EspañaFil: Cuadrado Vilanova, Maria. Hospital Sant Joan de Déu; EspañaFil: Castillo Ecija, Helena. Hospital Sant Joan de Déu; EspañaFil: Botteri, Gaia. Hospital Sant Joan de Déu; EspañaFil: Garcia Gerique, Laura. Hospital Sant Joan de Déu; EspañaFil: Moreno Gilabert, Helena. Hospital Sant Joan de Déu; EspañaFil: Gimenez Alejandre, Marta. No especifíca;Fil: Alonso Lopez, Patricia. No especifíca;Fil: Farrera Sal, Marti. No especifíca;Fil: Torres Manjon, Silvia. Instituto de Investigación Biomédica de Bellvitge; EspañaFil: Ramos Lozano, Dolores. Instituto de Investigación Biomédica de Bellvitge; EspañaFil: Moreno, Rafael. Instituto de Investigación Biomédica de Bellvitge; EspañaFil: Aerts, Isabelle. Centre National de la Recherche Scientifique; FranciaFil: Doz, François. Universite Paris Descartes; Francia. Centre National de la Recherche Scientifique; FranciaFil: Cassoux, Nathalie. Centre National de la Recherche Scientifique; Francia. Universite Paris Descartes; FranciaFil: Chapeaublanc, Elodie. Centre National de la Recherche Scientifique; FranciaFil: Torrebadell, Montserrat. Hospital Sant Joan de Déu; EspañaFil: Roldan, Monica. Hospital Sant Joan de Déu; EspañaFil: König, Andrés. No especifíca;Fil: Suñol, Mariona. Hospital Sant Joan de Déu; EspañaFil: Claverol, Joana. Hospital Sant Joan de Déu; EspañaFil: Lavarino, Cinzia. Hospital Sant Joan de Déu; EspañaFil: De Torres, Carmen. Hospital Sant Joan de Déu; EspañaFil: Fu, Ligia. Hospital Escuela Universitario; HondurasFil: Radvanyi, François. Centre National de la Recherche Scientifique; FranciaFil: Munier, Francis L.. Hopital Ophtalmique Jules Gonin; SuizaFil: Catalá-Mora, Jaume. Hospital Sant Joan de Déu; EspañaFil: Mora, Jaume. Hospital Sant Joan de Déu; EspañaFil: Alemany, Ramón. Instituto de Investigación Biomédica de Bellvitge; EspañaFil: Cascalló, Manel. No especifíca;Fil: Chantada, Guillermo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Montero Carcaboso, Angel. Hospital Sant Joan de Déu; Españ