The immune checkpoint
therapy is a relatively recent strategy that aims to tweak the immune system to effectively attack
cancer cells. The understanding of the immune responses and their regulation at the intracellular level and the development of fully
humanized monoclonal antibodies are the pillars of an approach that could elicit durable clinical responses and even remission in some patients with
cancer. Most of the immune checkpoints that regulate the T-cell responses (activation and inhibition) operate through
proteins present on the cytoplasmic membrane of the immune cells. Therefore, specific
antibodies capable of blocking the inhibitory signals should lead to unrestrained immune responses that supersede the inhibitory mechanisms, which are naturally present in the
tumor microenviroment. The best-known and most successful targets for immune checkpoint
therapy are the cytotoxic T-lymphocyte antigen-4 and programmed cell death-1 coreceptors.
Tremelimumab (CP-675,206) is a fully humanized
monoclonal antibody specific for cytotoxic T-lymphocyte antigen-4, which has been successfully used to treat patients with metastatic
melanoma and some other
cancers. Although still a work in progress, the use of
tremelimumab as an immune checkpoint therapeutic agent is a promising approach alone or in combination with other anticancer drugs. Here, we review the use of this antibody in a number of clinical trials against solid
tumors.