CID-165

CID-165 is a first-in-class, orally bioavailable macrocyclic inhibitor of cyclin D1, developed by Circle Pharma using its proprietary MXMO™ platform. It specifically targets the RxL motif to disrupt the protein-protein interaction between cyclin D1 and the retinoblastoma (Rb) protein. This mechanism leads to the suppression of phospho-Rb and subsequent G1 cell cycle arrest in cyclin D1-dependent tumor cells. CID-165 demonstrates high selectivity (>2,000-fold) for cyclin D1 over cyclin D3, potentially offering a wider therapeutic window and avoiding the adverse events associated with broader CDK4/6 inhibition. It is being developed for the treatment of various cyclin D1-driven malignancies, including ER-positive breast cancer, lymphomas, and other solid and hematological tumors.

Other names

Cyclin D1 RxL inhibitorCircle Pharma Cyclin D1 inhibitor