Targeting secondary immune responses to cetuximab: CD137 and the outside story.

Cetuximab is a murine-human chimeric IgG1 mAb directed against the EGFR that is approved for use in patients with colorectal and head and neck carcinomas. While some patients benefit greatly from cetuximab, many do not; therefore, strategies to increase the efficacy of this drug are of great clinical interest. In this issue of the JCI, Kohrt and colleagues report a strategy for enhancing the secondary immune response to cetuximab that involves sequential targeting with an agonist mAb against CD137 expressed on NK and T cells.