Phase 2 results from Radiation Therapy Oncology Group Study 0537: a phase 2/3 study comparing acupuncture-like transcutaneous electrical nerve stimulation versus pilocarpine in treating early radiation-induced xerostomia

Background: In this phase 2 component of a multi-institutional, phase 2/3, randomized trial, the authors assessed the feasibility and preliminary efficacy of acupuncture-like transcutaneous electrical nerve stimulation (ALTENS) in reducing radiation-induced xerostomia.

Methods: Patients with cancer of the head and neck who were 3 to 24 months from completing radiotherapy with or without chemotherapy (RT ± C) and who were experiencing xerostomia symptoms with basal whole saliva production ≥0.1 mL per minute and were without recurrence were eligible. Patients received twice weekly ALTENS sessions (24 sessions over 12 weeks) using a proprietary electrical stimulation unit. The primary study objective was to assess the feasibility of ALTENS treatment. Patients were considered compliant if 19 of 24 ALTENS sessions were delivered, and the targeted compliance rate was 85%. Secondary objectives measured treatment-related toxicities and the effect of ALTENS on overall radiation-induced xerostomia burden using the University of Michigan Xerostomia-Related Quality of Life Scale (XeQOLS).

Results: Of 48 accrued patients, 47 were evaluable. The median age was 60 years, 84% of patients were men, 70% completed RT ± C for >12 months, and 21% had previously received pilocarpine. Thirty-four patients completed all 24 ALTENS sessions, 9 patients completed 20 to 23 sessions, and 1 patient completed 19 sessions, representing a 94% total compliance rate. Six-month XeQOLS scores were available for 35 patients and indicated that 30 patients (86%) achieved a positive treatment response with a mean ± standard deviation reduction of 35.9% ± 36.1%. Five patients developed grade 1 or 2 gastrointestinal toxicity, and 1 had a grade 1 pain event.

Conclusions: The current results indicated that ALTENS treatment for radiation-induced xerostomia can be delivered uniformly in a cooperative, multicenter setting and produces possible beneficial treatment response. Given these results, the phase 3 component of this study was initiated.