Next generation of anti-PD-L1 Atezolizumab with better anti-tumor efficacy in vivo

Li, Maohua; Zhao, Rongqing; Chen, Jianxin; Tian, Wenzhi; Xia, Chenxi; Liu, Xudong; Li, Yingzi; Yan, Yuyuan; Li, Song; Sun, Hunter; Shen, Tong; Ren, Wenlin; Sun, Le

Some cancer patients treated with Atezolizumab, PD-L1 antibody drug launched by Genentech, quickly developed anti-drug antibody (ADA), led to loss of efficacy. This was likely due to the heavy aggregation of Atezolizumab, caused by mutation of N297A for removing unwanted antibody-dependent cytotoxicity (ADCC) of IgG1 antibody drug. Here, we developed a new version of Atezolizumab (Maxatezo), which was demonstrated better anti-tumor efficacy in vivo. In Atezolizumab, we mutated 297A to 297N back to bring back the glycosylation, and inserted a short sequence GGGS between G237 and G238 in the hinge region of the IgG1 heavy chain. Our data shown that insertion of GGGS, without altering the anti-PD-L1 antibody affinity and inhibitory activity, completely abolished the ADCC activity, as same as Atezolizumab. Moreover, the insertion of GGGS, without altering the glycosylation profile of IgG1, increased the yields of anti-PD-L1 antibody considerately. Additionally, glycosylation improved the stability yet reduced the amounts of aggregations in the antibody solutions. In turn, the level of ADA in animals treated with Maxatezo was 70% lower than the ones treated with Atezolizumab. Most importantly, at the same 10mg/kg dose, the anti-tumor activity of Maxatezo had attained 98% compared to that of Atezolizumab at 68%.