Next-Generation Covalent Drugs Developed With Improved Target Precision Through Strain Release

A new covalent warhead platform based on strain release, which could become central to the development of next-generation covalent drugs, has been developed and is drawing academic attention.

According to Chinese life sciences media outlet BioOn, a research team led by Zachary P. Shultz reported these findings in a paper published on Jan. 3 local time in the international journal Science.

Covalent drugs are changing the paradigm of targeted therapy by forming permanent chemical bonds with disease-associated proteins. However, most current drugs rely on a small number of highly reactive groups, such as acrylamides, which may cause off-target interactions.

The research team established a versatile platform that can replace the acrylamide covalent-reactive group in existing drug molecular structures. The key strategy was to introduce bicyclobutane and combine it with sulfur-containing functional groups commonly used in medicinal chemistry.

In particular, the team developed a reagent-based late-stage functionalization method that enables installation of the strain-release unit during the final stage of synthesis. This allows the structure of existing drugs to be maintained while systematically controlling covalent reactivity and target-binding ability.

The strain-release group showed high chemical selectivity for thiols, and its intrinsic reactivity could be precisely controlled through structural modifications. In cell experiments, the modified inhibitors maintained potent activity and effectively suppressed the target signaling pathway.

In addition, kinase profiling and whole-proteome analyses showed that the strain-release analogs had greater selectivity and markedly fewer off-target interactions than conventional acrylamide drugs.

Most importantly, experiments in preclinical mouse models demonstrated favorable pharmacokinetic properties and in vivo efficacy, increasing the potential for clinical application.

The research team explained, "Effective covalent inhibition depends not only on the intrinsic reactivity of the electrophile but also on its integration with molecular recognition," adding, "This study provides a new framework for designing more selective and clinically effective covalent therapies."