||||||||||STA551 / Roche Preclinical, Journal, IO biomarker: In vivo imaging with two-photon microscopy to assess the tumor-selective binding of an anti-CD137 switch antibody. (Pubmed Central) - May 6, 2022 In conclusion, we were able to assess switch antibody biodistribution in vivo through intravital imaging with two-photon microscopy. These results suggest that the tumor-selective binding of STA551 leads to a wide therapeutic window and potent antitumor efficacy without systemic immune activation.