Authors
Xiaojie Heng, Chaoyang Feng, Chenglong Wu, Tingting Yang, Dechun Ni, Jianglei Ma, Yiwen Bao, Jinkun Huang, Nan Zeng
Published in
European journal of medicinal chemistry. Volume 316. Pages 119054. Jun 10, 2026. Epub Jun 10, 2026.
Abstract
Antibody-drug conjugates (ADCs) combine the targeting specificity of monoclonal antibodies with the potent cytotoxicity of small-molecule drugs. However, ADC development using Exatecan, a potent topoisomerase I inhibitor, has been challenged by its hydrophobicity, leading to aggregation, rapid clearance, and off-target toxicity. Herein, we report the design of an intrinsically hydrophilic drug-linker platform (SMP-70067-L) that enables the construction of a homogeneous Exatecan-based HER2-targeted ADC (SMP-70067-X) with a high drug-to-antibody ratio (DAR of 7.92). Similar to Trastuzumab deruxtecan (DS-8201a), which achieves high DAR without PEG or polysarcosine chains through a hydrophilic self-immolative spacer, SMP-70067-L integrates minimal hydrophilic elements, including a glutamic acid residue and a modified aromatic self-immolative spacer, to balance hydrophilicity, stability, and efficient payload release. The resulting ADC exhibits low aggregation (<1%), favorable plasma and thermal stability, and sustained exatecan release. SMP-70067-X demonstrates potent cytotoxicity in HER2-positive tumor cells (sub-nanomolar IC50 values) and significantly enhanced antitumor efficacy compared to DS-8201a in HER2-moderate and HER2-low xenograft models. These results highlight the critical role of rational linker engineering in expanding the therapeutic window of hydrophobic topoisomerase I inhibitor-based ADCs.
PMID:
42296596
Bibliographic data and abstract were imported from PubMed on 16 Jun 2026.
Read full publication at:
Please sign in
to see all details.
Advertisement
Stats
- Recommendations n/a n/a positive of 0 vote(s)
- Views 9
- Comments 0