A clinical trial of a novel emulsion for potential use as a saliva substitute in patients with radiation-induced xerostomia

Researchers have recently developed a novel oily formulation for potential use as a saliva substitute for the treatment of dry mouth. The aim of this randomised, crossover study was to compare this new formulation to a currently available saliva substitute and a control of water on measures of mastication, subjective feeling of oral dryness and product acceptability. Forty participants treated with radiotherapy to the head and neck and experiencing xerostomia were invited to participate in the trial. Each participant trialled all three products in a randomised order. The effect of each product was measured using the Test of Masticating and Swallowing Solids (TOMASS), the Shortened Xerostomia Inventory (SXI) and a questionnaire designed to test patient acceptability of each product. Outcome data were gathered in a single session after the first administration of each product to evaluate immediate effects and after 7days of use to evaluate longer-term effects. Statistical analyses consisted of repeated-measures analysis of variance and mixed models. There was no evidence that application of the three formulations had an effect on any of the TOMASS measures, either immediately or after one week of use (P>0.05). There was a significant main effect of formulation on the SXI score (P=0.02). Application of the novel emulsion resulted in a clinically small but significant improvement in SXI score (P<0.01); however, application of methylcellulose (P=0.21) and water (P=0.81) resulted in no significant difference. There was no difference in participant acceptability between the three products (P=0.32). The novel oily emulsion showed no clinically significant benefit over two existing products for relief of xerostomia. Indeed, none of the three products demonstrated significant change in patient outcomes.