HDAC9 and neoplasm: HDAC inhibition also reduced tumour size in a genetic mouse model of CCOC.36 The combination of carboplatin with the HDAC inhibitor belinostat in platinum-resistant EOC saw a response rate of 7.4% (2/27) in a phase II study and did not proceed to a larger study.37 Another HDAC inhibitor, entinostat, in combination with olaparib was being evaluated in a phase I/II study38 which included patients with clear-cell gynaecological malignancies; however, this was terminated early in 2022 having enrolled 3 patients of a planned 73.