A multi-center trial is currently underway in Korea to assess the efficacy of combining Baekhogainsam-Tang (BIT), a traditional herbal formula, with low-dose pilocarpine for the treatment of intractable xerostomia, a persistent and bothersome dry mouth condition. The study, a randomized, open-label, parallel-group trial, aims to determine if this combination therapy can provide similar relief to high-dose pilocarpine while reducing the incidence of side effects.
Study Design and Patient Population
The trial is enrolling 120 patients diagnosed with Sjögren's syndrome or who have undergone radiotherapy to the head and neck, all of whom suffer from significantly reduced salivary flow. Participants are being randomly assigned to either the experimental group, receiving BIT herbal granules three times daily and 2.5mg of pilocarpine four times daily, or the control group, receiving 5mg of pilocarpine four times daily. The treatment duration is 12 weeks.
Key inclusion criteria include an unstimulated salivary flow rate (SFR) ≤0.25 mL/min and a visual analog scale (VAS) score for dry mouth ≥4. Exclusion criteria encompass various medical conditions such as heart failure, uncontrolled hypertension, and certain ophthalmic diseases, as well as the use of specific medications that could interfere with the trial or exacerbate xerostomia.
Endpoints and Assessments
The primary outcome measure is the unstimulated SFR after 12 weeks of treatment. Secondary outcomes include stimulated SFR, changes in VAS scores, assessments of oral health impact using the OHIP-14 questionnaire, and evaluations of quality of life using the EQ-5D-5L questionnaire. Salivary scintigraphy will also be performed to objectively evaluate salivary gland function.
Rationale for Combination Therapy
Pilocarpine, a muscarinic M3 receptor agonist, is a commonly prescribed sialagogue for xerostomia. However, high doses can lead to side effects such as sweating, nausea, and increased urinary frequency. BIT, on the other hand, has been used traditionally for symptoms like sore throat and thirst. Preclinical studies suggest that BIT may enhance the salivary secretion stimulated by pilocarpine, potentially allowing for a lower dose of pilocarpine to be used, thus minimizing side effects.
Potential Clinical Significance
Intractable xerostomia significantly impacts patients' quality of life. If the combination therapy proves to be both effective and well-tolerated, it could offer a valuable alternative for managing this challenging condition. The results of this trial are expected to be available by December 2024.
