Our invention relates to a novel anti-cancer therapy involving the silencing of tumour-derived immunosuppressive genes using siRNA.

Our invention relates to a novel anti-cancer therapy involving the silencing of tumour-derived immunosuppressive genes using siRNA. Indoleamine 2,3-doxygenase (IDO) is an immune suppressive molecule expressed across many different carcinomas and is believed to be a critical factor in protection of tumours from immune attack. In vitro and in vivo data obtained in mouse melanoma models have shown that tumour growth and formation can be successfully inhibited and delayed following gene silencing of IDO with siRNA. In vivo tumour formation in mice was delayed following inoculation ofin vitro IDO-siRNA silenced melanoma cells into sygeneic and allogeneic recipients. In addition, the in vivo treatment of melanoma-bearing mice with subcutaneous IDO-siRNA resulted in postpone-ment of tumour onset time and a significant decrease in tumour size. In vivo silencing of IDO with siRNA prevents tumour-induced T cell apoptosis and increased T cell directed tumour lysis. Additional in vivo studies are focused on optimizing the delivery of IDO-siRNA for tumour specific silencing. 

Our discovery has the potential to be developed as a new therapeutic for use in the treatment for cancer or as an adjunct for use in combination with conventional cancer treatments. The uniqueness of our novel strategy for the siRNA-based treatment of cancer is that only partial gene silencing is required to achieve the desired effect. Our strategy is considered both technically achievable and commercially viable and holds significant promise as a safer and less toxic therapeutic approach to the treatment of various cancers. Further information is available following the signing of a confidential disclosure agreement. 

Market Opportunity:  

Cancer is reported to affect more than 10 million people each year with the incidence continuing to rise. It is estimated that there are approximately 22 million people living with cancer worldwide of which about 6 million people are expected to die. The most common cancers include lung, breast, colon/rectum, stomach, liver, prostate, cervical, head/neck, esophageal, and bladder. Despite considerable efforts towards the development, there is currently no cure for cancer. Traditional or conventional treatment options (e.g., surgical intervention, chemo-therapy, radiation, biologics) help patients overcome the deteriorating affects of cancer. Although considerable progress has been made with the introduction of drugs with higher specificity for certain types of cancer but these treatment options have proven costly and are not yet widely available. Worldwide spending on cancer drugs totaled $22.3 billion last year and is expected to exceed $31.7 billion by the end of 2005.