Treatment of cancer cells with anti-CD3 × anti-tumour antigen and anti-CD28 × anti-tumour antigen cross-interacting bispecific antibodies led to enhanced tumour cell-dependent T-cell activation in vitro.53 Moreover, anti-CD28 × anti-PSMA and anti-CD28 × anti-mucin 16 (MUC16) bispecific antibodies were shown to potentiate in vivo anti-tumour activity of CD3+ bispecific T-cell redirectors in humanised immunocompetent mouse models of prostate and ovarian cancer, respectively.54 Importantly, combination therapy did not elicit toxicity in cynomolgus monkeys in vivo. This evidence concerns the gene CD28 and male reproductive organ cancer.