Gatapentin Enacarbil Effective for Severe Restless Legs Syndrome

Once-daily gabapentin enacarbil (Horizant) is effective in patients with the most severe cases of restless legs syndrome (RLS) and is associated with an adverse effect profile consistent with use in milder disease, according to research presented at the American Academy of Neurology 66th Annual Meeting in Philadelphia.

Lead researcher Daniel O. Lee, MD, of Baptist Health Neurology in Richmond, KY, said there is a strong association between severe RLS and cardiovascular risks.

Gabapentin enacarbil (GEn) is an actively transported prodrug of gabapentin that is approved for moderate to severe RLS. It differs from gabapentin in its chemical structure, pharmacokinetics, bioavailability, and rate of absorption.

Lee presented pooled data from 3 previous 12-week, double-blind, randomized trials that investigated a subset of patients with severe RLS who were taking GEn (600 mg [n = 80]), GEn [1200 mg (n = 119); or placebo (n =110]. The medication or placebo were taken once daily with food at 5 pm.

Severe RLS was defined as presence of symptoms for at least 15 days a month (not during treatment), RLS symptoms of 4 or more of the 7 consecutive evenings or days during the baseline period, and an international RLS (IRLS) total score of at least 15.

The study found statistically significant mean differences in IRLS score for both GEn 600 mg, versus placebo (-4; P = 0.03), and GEn, 1200 mg versus placebo (-5.7;P < 0.001). Compared with placebo, both doses of GEn significantly improved IRLS total score from baseline at each time point during the 12-week trial.

“We’re excited to say that this study demonstrated that even those individuals who suffer from severe RLS can benefit from gabapentin enacarbil,” said Lee.