CUDC-101 is a multi-targeted small molecule inhibitor primarily investigated for its potential in cancer therapy. It simultaneously inhibits histone deacetylase (HDAC), epidermal growth factor receptor (EGFR), and human epidermal growth factor receptor 2 (HER2). This unique triple inhibition mechanism enhances its anti-tumor activity by targeting multiple signaling pathways involved in cancer cell proliferation, survival, and metastasis. It has shown promising results in preclinical studies against various solid tumors and hematological malignancies, including lung, breast, and head and neck cancers. By blocking HDAC, CUDC-101 promotes the re-expression of tumor suppressor genes, while EGFR and HER2 inhibition disrupts downstream oncogenic signaling such as the PI3K/AKT and MAPK pathways. Due to its ability to overcome resistance mechanisms associated with single-target agents, CUDC-101 has been explored as a therapeutic option in resistant or relapsed cancers. It also demonstrates favorable pharmacokinetic properties and has entered early-phase clinical trials to evaluate safety and efficacy in humans. Its multi-target profile makes it a candidate for reducing the need for combination therapies, potentially minimizing drug interactions and side effects.