Phase I trials of single-agent new drugs in head and neck cancer: a scoping review

Background: The conventional method of drug development in oncology typically progresses through phase I, phase II and randomized phase III trials. Nevertheless, some recent drug approvals for head and neck cancer (HNC) relied on findings from single-arm phase II trials. This underscores the significance of disease-specific phase I trials as a crucial step in exploring new drugs for HNC patients. The purpose of this review is to present the currently available data of phase I clinical trials conducted in HNC and to provide an overview of ongoing therapeutic trends in HNC.

Methods: We performed a scoping review of phase I trials evaluating single-agent treatments specifically designed for HNC patients. The PubMed database was searched using "(phase I) AND (head and neck)". To ensure exhaustiveness, we also performed a search from the American Society of Clinical Oncology, European Society for Medical Oncology and American Association for Cancer Research websites.

Results: We screened 1,134 articles and selected 29 trials that met eligibility criteria, published between 1994 and 2023, for a total of 741 patients. Twenty-one trials comprised patients with different sites of HNSCC and only 8 trials (27%) focused on a specified subsite of head and neck. Most of trials investigated treatments in recurrent/metastatic (R/M) settings (86%). Immunotherapeutic agents were the most examined followed by targeted agents, cytotoxic drugs and "others" including a nanoparticle, a therapeutic gene, a fusion protein and a modulator of gene expression. Among trials reporting activity for R/M head and neck patients (n=23), the global median overall response rate (ORR) was 12% and four trials (17%) did not report any response. The incidence of grade 3/4 treatment-related adverse events (TRAEs) was low (7%). However, in seven trials safety results are not clearly assessable from the published data.

Conclusions: Phase I trials of single agents designed for head and neck patients were generally safe but with a low ORR. Future development of new drugs dedicated for HNC patients that can more accurately reflect the heterogeneity of HNC and provide more detailed subgroup analyses is warranted.