A replication incompetent adenovirus encoding the human pro-inflammatory cytokine interleukin-12 (IL-12) (INXN-2001) in combination with the proprietary activator ligand INXN-1001, with potential immunomodulating and antineoplastic activities. Production of IL-12 is controlled by an inducible DNA element that allows transcription initiation only in the presence of the ligand inducer. Upon intratumoral administration of INXN-2001 and oral administration of INXN-1001, INXN-1001 is able to induce expression of IL-12 from INXN-2001. IL-12 expressed by the adenovirus may activate the immune system by promoting the activation of natural killer cells (NKs), inducing secretion of interferon-gamma and inducing cytotoxic T cell responses against tumor cells, which may result in immune-mediated tumor cell death and inhibition of tumor cell proliferation.