ADC proteases for peptide linker——Screening and validation of linker

In the development of antibody-drug conjugates (ADCs), the linker plays a crucial role by connecting the antibody and cytotoxic payload, influencing key properties such as stability, potency, safety, and pharmacokinetics (PK). Selecting the appropriate linker is paramount for maximizing the therapeutic efficacy and safety of ADCs. An ideal linker should remain stable in the circulatory system and release the cytotoxic payload specifically within the tumor. However, linkers often lead to nonspecific release of payloads, resulting in off-target toxicity and narrowing the therapeutic window.

Linkers are typically classified as cleavable or non-cleavable based on their cleavage mechanism. Cleavable linkers can be efficiently triggered to release the cytotoxic payload in the tumor, with over 80% of clinically approved ADCs incorporating them. Current research in the ADC field primarily focuses on cleavable linkers, especially those cleaved by proteases like Cathepsin B. Ongoing investigations are also exploring the roles of other enzymes, including Cathepsin M, Cathepsin L, β-glucuronidase, and β-galactosidase, to further refine linker cleavage mechanisms and enhance the specificity and effectiveness of ADC therapies.

For the screening and validation of linkers for ADCs, we have developed a series of proteases specialized in linker cleavage, encompassing Cathepsin B, Cathepsin L, Cathepsin S, MMP-2, MMP-7, MMP-9, β-glucuronidase, and β-galactosidase.