Randomized placebo-controlled phase II trial of high-dose melatonin mucoadhesive oral gel for the prevention and treatment of oral mucositis in patients with head and neck cancer undergoing radiation therapy concurrent with systemic treatment

Purpose: The objective of this trial was to evaluate the safety and efficacy of melatonin oral gel mouthwashes in the prevention and treatment of oral mucositis (OM) in patients treated with concurrent radiation and systemic treatment for head and neck cancer. Methods: Randomized, phase II, double-blind, placebo-controlled trial (1:1 ratio) of 3% melatonin oral gel mouthwashes vs. placebo, during IMRT (total dose ≥ 66 Gy) plus concurrent Q3W cisplatin or cetuximab. Primary endpoint: grade 3–4 OM or Severe Oral Mucositis (SOM) incidence by RTOG, NCI, and a composite RTOG-NCI scales. Secondary endpoints: SOM duration and grade 2–4 OM or Ulcerative Oral Mucositis (UOM) incidence and duration. Results: Eighty-four patients were included in the study. Concurrent systemic treatments were cisplatin (n = 54; 64%) or cetuximab (n = 30; 36%). Compared with the placebo arm, RTOG-defined SOM incidence was numerically lower in the 3% melatonin oral gel arm (53 vs. 64%, P = 0.36). In patients treated with cisplatin, assessed by the RTOG-NCI composite scale, both SOM incidence (44 vs. 78%; P = 0.02) and median SOM duration (0 vs. 22 days; P = 0.022) were significantly reduced in the melatonin arm. Median UOM duration assessed by the RTOG-NCI scale was also significantly shorter in the melatonin arm (49 vs. 73 days; P = 0.014). Rate of adverse events and overall response rate were similar between the two arms. Conclusions: Treatment with melatonin oral gel showed a consistent trend to lower incidence and shorter SOM duration and shorter duration of UOM. These results warrant further investigation in phase III clinical trial.