Evaluation of antitumor response to HDAC inhibitors in advanced head and neck cancer: A proportional meta-analysis of clinical trials

Objective To study the cumulative proportion of favorable response to Histone Deacetylase Inhibitor (HDACi) among head and neck cancer (HNC) patients. Data Sources A systematic search (till 17 th -May-2025) was carried out in PubMed, Scopus, and Web of Science databases using “Head and Neck cancer” and “HDAC inhibitors” as key concept where all the single-arm clinical trials which have clear data on response to HDACi therapy-based RECIST criteria among HNC patients were included in this study. The meta-analysis was performed using R software. Data Summary The search resulted in a total of 178 articles, of which 7 studies were found to be relevant based on the inclusion criteria. Out of a total of 101 advanced HNC patients treated with HDACi in single-arm clinical trials, 74 patients showed favorable antitumor response. The pooled cumulative proportion of favorable response with the random effect model was found to be 0.65. Out of these 7 studies, the average proportion of antitumor response was calculated to be 0.758 among HNC patients who received HDACi concurrently with chemotherapy, chemoradiotherapy, and targeted therapy, whereas the average proportion of antitumor response rate to HDACi was 0.485 among priorly treated HNC patients. Vorinostat was the most used HDACi, where the proportion of favorable response was 0.49 compared to the non-vorinostat HDACi (0.77), like valproic acid, panobinostat, and romidepsin. Conclusion The overall antitumor response to HDACi was found to be 0.65 (65%), which supports the use of HDACi among advanced HNC patients, particularly along with the concurrent chemo/chemoradiotherapy or targeted therapy.