The inhibitory receptor CTLA4 has a key role in peripheral tolerance of T cells for both
normal and tumor-associated antigens. Murine experiments suggested that blockade of
CTLA4 might have antitumor activity and a clinical experience with the blocking antibody
ipilimumab in patients with metastatic melanoma did show durable tumor regressions in
some patients. Therefore, a phase II study of ipilimumab was conducted in patients with
metastatic renal cell cancer with a primary end point of response by Response Evaluation …