Breaking through poor selectivity in previous generation of protein kinase C (PKC) inhibitors, MS-533 has high selectivity and is significantly superior to previous generation ones in terms of safety, pharmacokinetic characteristics, and therapeutic efficacy, which is the only inhibitor of B cells receptor signaling pathway (BCR) that can target multiple drug-resistant variants on BTK and PLCG2.
The target of MS-553 is PKCβ, located in downstream of BTK and PLCG2, which is a key kinase of regulatory of this pathway.
Congeneric products like BTK inhibitors may lead to resistance mutations in BTK (C481) and PLCG2, even LOXO-305, a third-generation BTK inhibitor, led to novel resistance variants in BTK+PLCγ2.