Datopotamab Deruxtecan, a Novel TROP2-directed Antibody-drug Conjugate, Demonstrates Potent Antitumor Activity by Efficient Drug Delivery to Tumor Cells

Abstract

Trophoblast cell surface antigen 2 (TROP2) is highly expressed on various epithelial tumors and correlates with poor prognosis. We developed the novel TROP2-directed antibody-drug conjugate (ADC), datopotamab deruxtecan (Dato-DXd, DS-1062a), with a potent DNA topoisomerase I inhibitor (DXd), and evaluated its antitumor activity and safety profiles in preclinical models.The pharmacologic activity and mechanism of action of Dato-DXd were investigated in several human cancer cell lines and xenograft mouse models including patient-derived xenograft (PDX) models. Safety profiles were also assessed in rats and cynomolgus monkeys.Dato-DXd bound specifically to TROP2 and was internalized into tumor cells followed by intracellular trafficking to lysosome and DXd release, which induced DNA damage and apoptosis in TROP2-expressing tumor cells in vitro. Dato-DXd exhibited in vivo antitumor activity with DNA damage induced by the accumulated DXd in TROP2-expressing xenograft tumors, but neither isotype control IgG-ADC nor anti-TROP2 antibody had this effect. Dato-DXd also showed potent antitumor activity with tumor regression in several TROP2-expressing xenograft tumors including NSCLC PDX models. Safety profiles of Dato-DXd in rats and cynomolgus monkeys were acceptable.Dato-DXd demonstrated potent antitumor activity against TROP2-expressing tumors by efficient payload delivery into tumors and acceptable safety profiles in preclinical models. These results suggest Dato-DXd could be a valuable treatment option for patients with TROP2-expressing tumors in the clinical setting.

Graphical abstract

Figure 1.

Structures and characteristics of Dato-DXd. A, Schematic structure of Dato-DXd. B, DAR distribution of Dato-DXd. C, Binding specificity of Dato-DXd against human TROP family proteins. Recombinant proteins were incubated with Dato-DXd or isotype control ADC (control ADC) and binding activities were measured by ELISA. Each value represents the mean and SD of triplicates. D, Species cross-reactivity of Dato-DXd. CHO-K1 cells expressing human, cynomolgus monkey, rat and mouse TROP2 were incubated with Dato-DXd and binding activities were measured by cell-based ELISA. Each value represents the mean and SD of triplicates. E,In vitro stability of Dato-DXd in plasma. The release rate at each timepoint was calculated using the mean concentration of the released DXd (N = 3). F, Pharmacokinetics of Dato-DXd in cynomolgus monkeys. Dato-DXd was intravenously administered to cynomolgus monkeys at the dose of 6 mg/kg and the concentrations of Dato-DXd, total antibody and DXd in plasma were determined. Each value represents the mean and SD (N = 3).

Figure 2.

Dato-DXd dynamics and effects on cancer cells. A, Internalization rate of Dato-DXd. Each cancer cell line was treated with Alexa 488-labeled Dato-DXd and the internalization rates were measured as described in Materials and Methods. Each data represent the mean and SD of three or four independent experiments. B, Correlation between TROP2 expression and DXd release. TROP2 expression level on each cancer cell line was determined by flow cytometry. The DXd concentration in the culture media at 24 hours after the treatment with 100 nmol/L Dato-DXd was determined by LC/MS-MS and the average of two independent experiments of triplicates were used for correlation analysis (Spearman rank correlation coefficient: ρ = 0.60). C, Intracellular trafficking of Dato-DXd to lysosome. BxPC-3 cells treated with Alexa 488-labeled Dato-DXd (green) were costained with anti-LAMP2 antibody (red) and DAPI (blue), and analyzed by confocal microscopy. Bars represent 10 μm for confocal images (top) and STED images (bottom). D, DNA damage and apoptosis induced by Dato-DXd. NCI-N87 cells treated with Dato-DXd or controls for up to 72 hours were analyzed by Western blot analysis for DNA damage markers (γH2AX, pKAP1, and pChk1) and apoptosis markers (cleaved PARP and caspase 3).

Figure 3.

Pharmacokinetic and pharmacodynamic analysis of Dato-DXd in NCI-N87 xenograft mouse model. Mice inoculated with NCI-N87 cells were intravenously administered with Dato-DXd, control ADC, datopotamab (10 mg/kg) or vehicle on day 0. A, Antitumor activity of Dato-DXd and controls. Each value represents the mean and SE (N = 6), and statistically significant difference compared with the vehicle control analyzed by Dunnett multiple comparison test (*, P < 0.01). Plasma concentration of Dato-DXd, total Ab, and DXd (B), and tumor concentration of DXd (C) in NCI-N87 xenograft mice treated with Dato-DXd. Each value represents the mean and SD (N = 3). Plasma concentration of ADC, total Ab or DXd on day 1 in NCI-N87 xenograft mice treated with Dato-DXd, control ADC or Datopotamab (D), and tumor concentration of DXd on day 1 in NCI-N87 xenograft mice treated with Dato-DXd or control ADC (E). Each value represents the mean and SD (N = 3). F, IHC analysis for γH2AX on NCI-N87 xenograft tumors treated with Dato-DXd, control ADC, or datopotamab. Each value represents the mean (red bar) and individual data (light blue; N = 3). Representative images for pretreatment tumor, tumors treated with Dato-DXd on days 1, 3, and 7, and tumors treated with control ADC or datopotamab on day 1 were also shown.

Figure 4.

Antitumor activity of Dato-DXd in NSCLC xenograft models. A, NSCLC CDX mice were intravenously administered with Dato-DXd, control ADC (10 mg/kg) or vehicle on day 0. Each value represents the mean and SE (N = 6), and statistically significant difference compared with the vehicle control analyzed by Dunnett multiple comparison test (*, P < 0.01). Representative TROP2 IHC images and H-scores for each model were also shown. B, NSCLC PDX mice were intravenously administered with Dato-DXd (10 mg/kg) or vehicle on day 0. Each value of tumor volume represents the mean and SE (N = 5), and statistically significant difference compared with the vehicle control analyzed by unpaired t test (*, P < 0.01). Representative TROP2 IHC images and H-scores for each model were also shown.