Glutamic acid\u2013valine\u2013citrulline linkers ensure stability and efficacy of antibody\u2013drug conjugates in mice

Yasuaki Anami,Ningyan Zhang,Chisato M Yamazaki,Xun Gui,Wei Xiong,Kyoji Tsuchikama,Zhiqiang An

doi:10.1038/s41467-018-04982-3

Abstract

Valine–citrulline linkers are commonly used as enzymatically cleavable linkers for antibody–drug conjugates. While stable in human plasma, these linkers are unstable in mouse plasma due to susceptibility to an extracellular carboxylesterase. This instability often triggers premature release of drugs in mouse circulation, presenting a molecular design challenge. Here, we report that an antibody–drug conjugate with glutamic acid–valine–citrulline linkers is responsive to enzymatic drug release but undergoes almost no premature cleavage in mice. We demonstrate that this construct exhibits greater treatment efficacy in mouse tumor models than does a valine–citrulline-based variant. Notably, our antibody–drug conjugate contains long spacers facilitating the protease access to the linker moiety, indicating that our linker assures high in vivo stability despite a high degree of exposure. This technology could add flexibility to antibody–drug conjugate design and help minimize failure rates in pre-clinical studies caused by linker instability.

Highlights

Valine–citrulline linkers are commonly used as enzymatically cleavable linkers for antibody–drug conjugates
Our findings indicate that the use of the EVCit linker system could minimize failure rates in preclinical studies using mouse models caused by linker instability, significantly expanding flexibility in designing Antibody–drug conjugates (ADCs)
Based on a report by Dorywalska and co-workers[23], we expected that probes 1b, f would serve as mimics of the hydroxy-functionalized tripeptide ADC linker with increased mouse plasma stability

Summary

Introduction

Valine–citrulline linkers are commonly used as enzymatically cleavable linkers for antibody–drug conjugates. We report that an antibody–drug conjugate with glutamic acid–valine–citrulline linkers is responsive to enzymatic drug release but undergoes almost no premature cleavage in mice. We demonstrate that this construct exhibits greater treatment efficacy in mouse tumor models than does a valine–citrulline-based variant. ADCs consist of potent drugs (payloads) linked to therapeutic monoclonal antibodies (mAbs) through chemical linkers This molecular format enables pinpoint delivery of highly cytotoxic payloads to target tumor cells, resulting in greater potency, a broader therapeutic window, and more durable treatment effect than are possible with traditional chemotherapy agents alone[15, 16]. We demonstrate that an ADC constructed a Conventional VCit linker mAb

Methods

Results

Conclusion