Syngeneic mouse melanoma and colorectal tumour models with murine/human chimeric atezolizumab; tumour growth reduced by at least 80%
“For in vivo pharmacology studies, the Applicant generated murine/human chimeric antibodies of atezolizumab to minimize immunogenicity in mice and evaluated PD-L1 blockade in syngeneic mouse models of melanoma and colorectal cancer. Anti-PD-L1 antibody reduced tumor growth by ≥ 80%.”
✓ VerifiedFDA pharmacology/toxicology review, p. 12Source ↗
Why that model
Chimeric mouse IgG2a versions used to reduce immunogenicity seen in earlier mouse studies
“The Applicant generated mouse IgG2a/human chimeric antibodies for murine in vivo studies in order to reduce immunogenicity, which was observed in prior mouse studies.”
✓ VerifiedFDA pharmacology/toxicology review, p. 4Source ↗
Reviewer's view of the efficacy data
EMA: syngeneic tumour models with chimeric mAbs adequately evaluated PD-L1 blockade and provide sufficient proof-of-concept
“The in vivo effect of blocking PD-L1 was adequately evaluated in murine syngeneic tumour models using chimeric anti-PD-L1 mAbs. These studies demonstrate that treatment with anti-PD-L1 mediates an effective anti-tumour response and provide sufficient proof-of-concept.”