Cervera-Carrascon et al. make use of an adenovirus equipped with the ability to express tumor necrosis factor alpha (TNFα) and interleukin-2 (IL-2), two key inflammatory cytokines, in combination with anti-PD-1 therapy in murine models to eliminate B16.OVA melanoma tumors. ‘Priming’ with virotherapy and ‘boosting’ with anti-PD-1 treatment increased the frequency of intratumoral cytotoxic CD8+ T cells, IL-4, IL-6, IL-10, and IL-17A compared to simultaneous treatments. The prime and boost approach demonstrated 100% tumor regression and survival.

Releasing the patient's immune system against their own malignancy by the use of checkpoint inhibitors is delivering promising results. However, only a subset of patients currently benefit from them. One major limitation of these therapies relates to the inability of T cells to detect or penetrate into the tumor resulting in unresponsiveness to checkpoint inhibition. Virotherapy is an attractive tool for enabling checkpoint inhibitors as viruses are naturally recognized by innate defense elements which draws the attention of the immune system. Besides their intrinsic immune stimulating properties, the adenoviruses used here are armed to express tumor necrosis factor alpha (TNFa) and interleukin-2 (IL-2). These cytokines result in immunological danger signaling and multiple appealing T-cell effects, including trafficking, activation and propagation. When these viruses were injected into B16.OVA melanoma tumors in animals concomitantly receiving programmed cell-death protein 1 (PD-1) blocking antibodies both tumor growth control (p < 0.0001) and overall survival (p < 0.01) were improved. In this set-up, the addition of adoptive cell therapy with OT-I lymphocytes did not increase efficacy further. When virus injections were initiated before antibody treatment in a prime-boost approach, 100% of tumors regressed completely and all mice survived. Viral expression of IL2 and TNFa altered the cytokine balance in the tumor microenvironment towards Th1 and increased the intratumoral proportion of CD8+ and conventional CD4+ T cells. These preclinical studies provide the rationale and schedule for a clinical trial where oncolytic adenovirus coding for TNFa and IL-2 (TILT-123) is used in melanoma patients receiving an anti-PD-1 antibody.

Author Info: (1) (2) (3) (4) (7) TILT Biotherapeutics Ltd, Helsinki, Uusima, Finland; and Department of Oncology, Cancer Gene Therapy Group, Faculty of Medicine, University of Helsinki

Author Info: (1) (2) (3) (4) (7) TILT Biotherapeutics Ltd, Helsinki, Uusima, Finland; and Department of Oncology, Cancer Gene Therapy Group, Faculty of Medicine, University of Helsinki, Helsinki, Uusima, Finland. (5) Department of Oncology, Cancer Gene Therapy Group, Faculty of Medicine, University of Helsinki, Helsinki, Uusima, Finland. (6) Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Uusima, Finland. (8) Department of Oncology, Cancer Gene Therapy Group, Faculty of Medicine, University of Helsinki, Helsinki, Uusima, Finland; and Department of Obstetrics and Gynecology, Helsinki University Central Hospital, Helsinki, Uusima, Finland. (9) TILT Biotherapeutics Ltd, Helsinki, Uusima, Finland; and Department of Oncology, Cancer Gene Therapy Group, Faculty of Medicine, University of Helsinki, Helsinki, Uusima, Finland; and Helsinki University Hospital Comprehensive Cancer Center, Helsinki, Uusima, Finland.

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