Inducible T-Cell Costimulator (ICOS)

T-cell activity is controlled by the interaction of a diverse network of ligands and receptors.1,2 The inducible T-cell costimulator (ICOS), a CD28 family member and important regulator of the adaptive immune response, is found on the surface of certain T cells, and its expression is upregulated upon stimulation by binding to the T-cell receptor (TCR).1,2,3 ICOS stimulation results in a costimulatory signal that may ultimately enhance T-cell function, including activity against tumor cells.4 ICOS is also present on a set of T regulatory cells.5 Targeting ICOS in cancer may potentially have a dual effect of modifying Tcell activity and depleting intratumoral T regulatory cells with high ICOS expression.5

The safety and efficacy of the agents and/or uses under investigation have not been established. There is no guarantee that the agents will receive health authority approval or become commercially available in any country for the uses being investigated.


  1. Simpson TR, et al. Curr Opin Immunol. 2010;22:326-332.
  2. Sharpe AH. Immunol Rev. 2009;229:5-11.
  3. McAdams AJ, et al. J Immunol. 2000;165:5035-5040.
  4. Fan X, et al. J Exp Med. 2014;211:715-725.
  5. Michaelson JS, et al. Cancer Res. 2016;76(suppl)[abstract 573].