An updated patent review of histone deacetylase (HDAC) inhibitors in cancer (2020–present)

Introduction: Histone deacetylase (HDAC) inhibitors have been considered as an attractive strategy to reverse aberrant epigenetic changes associated with cancer treatments. The use of HDAC inhibitors in various cancer types has continued to develop for decades, bringing several novel HDAC inhibitors successfully into clinical trials. The combination use of HDAC inhibitors with other agents have also been developed and have demonstrated superior efficacy compared to that of monotherapy in recent studies. Hence, development of new anticancer treatment and therapeutic regimen is necessary. Areas covered: This review summarizes a comprehensive review of the patent literature from 2020 to 2022 including HDAC inhibitors and their use as anticancer agents (searched from European Patent Office, 2020–2022). The approved and developing HDAC inhibitors are described. It also provides perspectives on the challenges and future opportunities. Expert opinion: Although hundreds of clinical trials of HDAC inhibitors are still going on, the application for HDAC inhibitors has been limited at present. Not only in the anticancer treatment, but also non-oncology disease therapies are being investigated eagerly. Recently, applications of HDAC inhibitors in non-oncology diseases have also been revealed and proceeded to clinical trials. New indications for HDAC inhibitors are needed urgently in the future.