The limited efficacy of cancer immunotherapy is usually attributed to suboptimal antitumor T-cell generation, as well as impaired immunological memory development. MDX-2004 is a trispecific antibody-fusion protein developed by Modex Therapeutics Inc. that targets CD3, CD28 and CD137 on human T cells, which was designed to overcome these limitations by rejuvenating the immune system and enhancing antitumor immunity.