Overcoming immune tolerance against tumor self-antigens is a goal of intense research in the design of cancer therapies. One approach to enhance immune system activation against tumor antigens is to bl;ock the inhibitory co-stimulatory signals mediated by cytotoxic T lymphocyte antigen 4, (CTLA-4) expressed on activated T cells. The CP-675 is one of several fully human monoclonal antibodies that are directed against human CTLA-4, ipilimumab (Medarex/Bristol-Myers Squibb) and CP-675,206 (Pfizer/Abgenix, now Amgen), that have demonstrated activity against metastatic melanoma, hormone refractory prostate cancer and other malignancies. A recent review concluded: “CTLA4 blockade with tremelimumab at 15 mg/kg every 3 months has demonstrated substantial antitumor activity and an overall safe profile in patients with advanced melanoma. Phase III studies in melanoma and earlier stages of clinical development in colorectal, pancreatic, breast, and non-small cell lung carcinomas are ongoing.”
Camacho L LH Novel therapies targeting the immune system: CTLA4 blockade with tremelimumab (CP-675,206), a fully human monoclonal antibody. Expert opinion on investigational drugs 2008 Mar 1; 17(3):371-85
Keilholz, Ulrich CTLA-4: Negative Regulator of the Immune Response and a Target for Cancer Therapy. Journal of Immunotherapy. 31(5):431-439, June 2008.