OPN-6602

OPN-6602 is an oral, potent, and selective small molecule inhibitor of the EP300 (E1A binding protein p300) and CBP (CREB-binding protein) bromodomains. These proteins are key transcriptional co-activators with histone acetyltransferase activity that regulate gene expression via chromatin remodeling. In multiple myeloma, EP300/CBP drive the expression of critical oncogenic factors such as IRF4 and MYC. By inhibiting these targets, OPN-6602 induces cell cycle arrest and apoptosis in multiple myeloma cells through suppression of IRF4 and MYC. Preclinical studies have shown significant antitumor activity both as monotherapy (71% tumor suppression in models) and in combination with standard-of-care agents like dexamethasone, pomalidomide, or mezigdomide (100% tumor regression). The drug is currently being evaluated in a phase 1 clinical trial for relapsed/refractory multiple myeloma. Developed by Opna Bio, OPN-6602 has received orphan drug designation from the FDA for this indication[1][2][3][5][6][7][8].