HDAC9 and hematologic disorder: Moreover, more than 10 other HDAC inhibitors have undergone or are undergoing clinical trials as monotherapy or in combination therapy in patients with hematologic malignancies or solid tumors.452,453 For example, the benzamide inhibitor entinostat is currently assessed in phase III trials (NCT02115282 and NCT03538171) for the clinical benefit in patients with HR-positive, HER2-negative, locally advanced, or metastatic breast cancer.