Efficacy of lamotrigine in the management of chemotherapy-induced peripheral neuropathy: a phase 3 randomized, double-blind, placebo-controlled trial, N01C3

BACKGROUND: Lamotrigine, an antiepileptic agent, has been reported as being effective in reducing symptoms of neuropathy associated with various etiologies. Based on such data, a multicenter double-blind, placebo-controlled, randomized trial was conducted to evaluate the effect of lamotrigine on pain and other neuropathic symptoms due to chemotherapy-induced peripheral neuropathy (CIPN). METHODS: Patients with symptomatic CIPN with symptom scores of either 1) >3 on a 0-10 Numerical Rating Scale (NRS) or 2) >1 on the 0-3 the Eastern Cooperative Oncology Group (ECOG) neuropathy scale (ENS) were eligible (higher numbers corresponding to greater severity of symptoms in both scales). Patients were randomly assigned to receive lamotrigine (target dose of 300 mg/day) or placebo for 10 weeks. Endpoints were measured biweekly. RESULTS: In all, 131 patients were enrolled. Both groups were well matched at baseline. Over the 10-week period of the trial, the average pain scores (NRS) for the lamotrigine and placebo arms declined in both arms, with no statistically significant difference noted between the changes in the 2 groups (0.3 and 0.5 unit reduction from baseline, respectively; P=.56). Similarly, decreases in the ENS with therapy were not statistically different (0.4 and 0.3, respectively; P=.3). Changes in other subjective symptom scales were also not found to be statistically different between the 2 groups. Toxicities were mild and similar in each group. CONCLUSIONS: The results suggest that lamotrigine is not effective for relieving neuropathic symptoms in patients because of CIPN.