TNF and inflammatory bowel disease: 2009; Kaymakcalan et al. 2009). Certolizumab and etanercept also demonstrated a reduced clinical efficacy as compared to infliximab and adalimumab in the treatment of inflammatory bowel diseases (IBD), thereby suggesting that the CDC and ADCC activity of the mAbs may play a role in the IBD. Given that the efficacy in IBD diseases beyond Fab–TNFα interactions may also depend on the ADCC‐related Fc and FcγRIIIA interactions, we would expect that our Chimera 2 should be more efficient than Chimera 1A in treating inflammatory TNFα‐related diseases including IBD.