Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan.
Gilead Sciences, Inc., Morris Plains, New Jersey.
Mol Cancer Ther. 2023 Jan 3;22(1):102-111. doi: 10.1158/1535-7163.MCT-22-0375.
Antibody-drug conjugates (ADC) are a rapidly growing class of targeted cancer treatments, but the field has experienced significant challenges from their complex design. This study examined the multiscale distribution of sacituzumab govitecan (SG; Trodelvy), a recently clinically approved ADC, to clarify the mechanism(s) of efficacy given its unique design strategy. We employed a multiscale quantitative pharmacokinetic approach, including near-infrared fluorescence imaging, single-cell flow cytometry measurements, payload distribution via γH2AX pharmacodynamic staining, and a novel dual-labeled fluorescent technique to track the ADC and payload in a high trophoblast cell-surface antigen 2 expression xenograft model of gastric cancer (NCI-N87). We found that rapid release of the SN-38 payload from the hydrolysable linker inside cells imparts more DNA damage in vitro and in vivo than an ADC with a more stable enzyme cleavable linker. With SG, little to no extracellular payload release in the tumor was observed using a dual-labeled fluorescence technique, although bystander effects were detected. The high dosing regimen allowed the clinical dose to reach the majority of cancer cells, which has been linked to improved efficacy. In addition, the impact of multiple doses (day 1 and day 8) of a 21-day cycle was found to further improve tissue penetration despite not changing tumor uptake [percent injected dose per gram (%ID/g)] of the ADC. These results show increased ADC efficacy with SG can be attributed to efficient tumor penetration and intracellular linker cleavage after ADC internalization. This quantitative approach to study multiscale delivery can be used to inform the design of next-generation ADCs and prodrugs for other targets.
抗体药物偶联物（ADC）是一类快速发展的靶向癌症治疗药物，但由于其复杂的设计，该领域面临着重大挑战。本研究通过多尺度定量药代动力学方法，包括近红外荧光成像、单细胞流式细胞术测量、通过 γH2AX 药效学染色进行有效载荷分布以及一种新型双标记荧光技术，研究了最近临床批准的 ADC——注射用Sacituzumab govitecan（SG；Trodelvy）的多尺度分布，以阐明其独特设计策略下的疗效机制。我们研究了一种多尺度定量药代动力学方法，包括近红外荧光成像、单细胞流式细胞术测量、通过 γH2AX 药效学染色进行有效载荷分布以及一种新型双标记荧光技术，用于跟踪 ADC 和有效载荷在高滋养层细胞表面抗原 2 表达胃癌异种移植模型（NCI-N87）中的分布。我们发现，与具有更稳定酶可裂解接头的 ADC 相比，细胞内可水解接头快速释放 SN-38 有效载荷会导致更多的体外和体内 DNA 损伤。使用双标记荧光技术，在肿瘤中观察到 SG 几乎没有细胞外有效载荷释放，尽管检测到旁观者效应。高剂量方案使临床剂量能够到达大多数癌细胞，这与疗效的提高有关。此外，尽管未改变 ADC 的肿瘤摄取量（每克注射剂量的百分比[ID/g]），但发现 21 天周期中第 1 天和第 8 天的多次剂量（2 个剂量）会进一步改善组织穿透性。这些结果表明，SG 的 ADC 疗效增加可归因于 ADC 内化后有效的肿瘤穿透和细胞内接头断裂。这种多尺度递药的定量方法可用于为其他靶点的下一代 ADC 和前药设计提供信息。
