Characterization of a recombinant gorilla-adenovirus HPV therapeutic vaccine (PRGN-2009).

There are approximately 44,000 cases of human papilloma virus (HPV)‒associated cancer each year in the United States, most commonly caused by HPV16/18. Prophylactic vaccines successfully prevent healthy people from acquiring HPV infections via HPV-specific antibodies. To treat established HPV-associated malignancies, however, new therapies are necessary. Multiple recombinant gorilla adenovirus HPV vaccine constructs were evaluated in NSG β2m-/- peripheral blood mononuclear cell-humanized mice bearing SiHa, a human HPV16+ cervical tumor, and/or in the syngeneic HPV16+ TC-1 model. PRGN-2009 is a new therapeutic gorilla adenovirus HPV vaccine containing multiple cytotoxic T-cell epitopes of the viral oncoproteins HPV 16/18 E6 and E7, including T-cell enhancer agonist epitopes. PRGN-2009 treatment reduced tumor volume and increased CD8 and CD4 T cells in the tumor microenvironment of humanized mice bearing the human cervical tumor SiHa. PRGN-2009 monotherapy in the syngeneic TC-1 model also reduced tumor volumes and weights, generated high levels of HPV16 E6-specific T cells, and increased multifunctional CD8 and CD4 T cells in the tumor microenvironment. These studies provide the first evaluation of a therapeutic gorilla adenovirus HPV vaccine, PRGN-2009, showing promising preclinical anti-tumor efficacy and induction of HPV-specific T cells, and the rationale for its evaluation in clinical trials.