RMC-5552

RMC-5552 is a selective bi-steric inhibitor of the raptor-mammalian target of rapamycin complex 1 (mTORC1). It functions by selectively binding to and inhibiting the serine/threonine kinase activity of mTORC1, which leads to suppression of phosphorylation and inactivation of 4EBP1, a key translational regulator involved in oncogene expression. This inhibition decreases expression of mRNAs necessary for cell cycle progression, inducing cell cycle arrest and tumor cell apoptosis. RMC-5552 shows potent inhibition with high selectivity for mTORC1 over mTORC2 (approximately 40-fold), improving tolerability compared to non-selective inhibitors. It has demonstrated antitumor activity in preclinical models and is currently under clinical evaluation primarily for cancers with activated mTORC1 signaling such as solid tumors including head and neck cancer, KRAS-mutated non-small cell lung cancer, recurrent glioblastoma, and lymphangioleiomyomatosis (LAM). The drug is administered intravenously on a weekly schedule.