Gene therapy for prostate cancer - Research and development of a new immuno-gene therapy

We have performed three clinical studies for prostate cancer at Okayama University Hospital. In the first study (Suicide gene therapy using adenovirus vector (ADV) expressing herpes simplex virus-thymidine kinase gene and Ganciclovir), 9 castration-resistant prostate cancer (CRPC) patients without metastasis were treated from 2001 to 2005, demonstrating the safety profile and some clinical responses. In the second study (Immunogene therapy using ADV expressing the Interleukin-12 gene), 10 CRPC patients with or without metastasis were treated from 2008, demonstrating the safety profile and some immuno-clinical responses. The latest study (Gene therapy creating cancer vaccine using ADV expressing reduced expression in immortalized cells; REIC/Dkk-3 gene, which mediates simultaneous induction of cancer-selective apoptosis and augmentation of anti-tumor immunity), was initiated in Jan., 2011. The study category includes 2 groups: A, CRPC; and B, newly diagnosed high-risk localized cancer with indication for surgical resection (Neo-adjuvant). Four CRPC patients and 9 neo-adjuvant patients have been entered into the study with an excellent safety profile. Patients treated with the intermediate vector dose demonstrated modest clinical and/or immunological effects, and an increased vector dose showed remarkable immuno-pathological effects. Ad/REIODkk-3, a revolutionary gene-based medicine creating a cancer vaccine, could be a promising treatment option for prostate cancer.