Creative Biolabs can provide several noncleavable alkyl and polymeric linkers, such as the notablely successful MCC amine-to-sulfhydryl bifunctional cross-linker featured in T-DM1. This linker is especially useful as the cyclohexane ring provides steric hindrance that decreases the rate of hydrolysis of the resulting thioether. Non-cleavable thioether linkers, succinimide-thioether bonds that formed by the reaction of maleimids with thiols, have also been commonly used to link auristatin derivatives to monoclonal antibodies.