12135 Background: Prophylactic gabapentin decreases pain, opioid use, and weight loss in head and neck (HNC) patients treated with chemoradiotherapy. Nonetheless, significant symptom burden remains. Ketamine is an NMDA receptor antagonist which has neuromodulator and anti-inflammatory properties. We undertook a phase I/II study to explore safety, feasibility, and obtain preliminary efficacy data pertaining to the combination of ketamine and gabapentin in HNC patients undergoing radiation +/- chemotherapy. Results of the phase I study were previously reported. Herein we report preliminary results of the phase II portion of the study. Primary outcomes were toxicity and feasibility; secondary outcomes were symptom burden. Methods: Eligibility: locally advanced HNC patients planned for primary or adjuvant radiotherapy +/- chemotherapy. Treatment: Day 1: gabapentin 100 mg PO TID; Day 8: increase gabapentin to 300 mg PO TID; Day 15: continue gabapentin and start intranasal ketamine 30 mg TID. Dose modifications were allowed for both agents. Toxicity: assessed using CTCAE 5.0. Feasibility: data capture by pill counts and patient medication logs. Efficacy: patient reported outcomes measures completed at baseline, weekly during radiation and 1-, 2-, and 3-months post-radiation. Results: Patient characteristics: median age 60 yrs, 85% males, 67% p16-positive, 21 post-operative. Toxicity: Of 45 patients who completed treatment, 7 patients (16%) experienced a grade 2+ toxicity (5 were probably related to ketamine). Four patients required ketamine dose de-escalation due to dizziness. Six patients (13%) eventually discontinued ketamine due to toxicity. Feasibility: 41 (91%) patients missed 90 days. Conclusions: The combination of gabapentin and ketamine was safe and feasible. Preliminary data indicates the majority of patients experienced low to moderate levels of pain with minimal use of opioids. Larger, randomized studies are warranted to confirm the benefit of the combination of gabapentin and ketamine. Clinical trial information: NCT05156060 .
Lockney et al. (Wed,) studied this question.