MPK409

**MPK409** is an investigational **small-molecule histone deacetylase inhibitor** developed in an academic research setting as a novel epigenetic anticancer agent. Published preclinical work identifies it as one of a series of new HDAC inhibitors with **selectivity toward class I HDACs and HDAC6**, showing antiproliferative and pro-apoptotic activity in models of **germ cell tumors, urothelial carcinoma, renal cell carcinoma, and prostate cancer**, including cisplatin-resistant disease. It appears to remain a **preclinical research compound** rather than a clinically developed pharmaceutical product, with no clear evidence of commercial branding, regulatory approval, or advanced human clinical development.