Communications
作者: Christie, R James ; Yuan, Jiaqi ; Vijayakrishnan, Balakumar ; Davies, Michael ; Wortmann, Philipp ; Anderton, Judith ; Tosto, Frances Anne ; Chesebrough, Jon ; Wallez, Yann ; Novick, Steven ; Dimasi, Nazzareno ; Luheshi, Nadia ; McFarlane, Mary ; Howard, Philip W ; Sabol, Darrin ; Tice, David A ; Masterson, Luke ; Leo, Elisabetta ; Dickinson, Niall J ; Cailleau, Thais ; Cooper, Zachary A ; Kinneer, Krista ; Huang, Yue ; Ball, Kathryn ; Monks, Noel ; Wang, Jixin ; Albertella, Mark R ; Lewis, Arthur ; Staniszewska, Anna D ; Sapra, Puja ; Hutchinson, Ian ; Rosenbaum, Anton I
PURPOSE:We evaluated the activity of AZD8205, a B7-H4-directed antibody-drug conjugate (ADC) bearing a novel topoisomerase I inhibitor (TOP1i) payload, alone and in combination with the PARP1-selective inhibitor AZD5305, in preclinical models.
EXPERIMENTAL DESIGN:IHC and deep-learning-based image analysis algorithms were used to assess prevalence and intratumoral heterogeneity of B7-H4 expression in human tumors. Several TOP1i-ADCs, prepared with Val-Ala or Gly-Gly-Phe-Gly peptide linkers, with or without a PEG8 spacer, were compared in biophysical, in vivo efficacy, and rat toxicology studies. AZD8205 mechanism of action and efficacy studies were conducted in human cancer cell line and patient-derived xenograft (PDX) models.
RESULTS:Evaluation of IHC-staining density on a per-cell basis revealed a range of heterogeneous B7-H4 expression across patient tumors. This informed selection of bystander-capable Val-Ala-PEG8-TOP1i payload AZ14170133 and development of AZD8205, which demonstrated improved stability, efficacy, and safety compared with other linker-payload ADCs. In a study of 26 PDX tumors, single administration of 3.5 mg/kg AZD8205 provided a 69% overall response rate, according to modified RECIST criteria, which correlated with homologous recombination repair (HRR) deficiency (HRD) and elevated levels of B7-H4 in HRR-proficient models. Addition of AZD5305 sensitized very low B7-H4-expressing tumors to AZD8205 treatment, independent of HRD status and in models representing clinically relevant mechanisms of PARPi resistance.
CONCLUSIONS:These data provide evidence for the potential utility of AZD8205 for treatment of B7-H4-expressing tumors and support the rationale for an ongoing phase 1 clinical study (NCT05123482). See related commentary by Pommier and Thomas, p. 991.