LAS VEGAS—Overall, gabapentin enacarbil was associated with lower incidences of peripheral edema and weight gain than pregabalin, according to authors of a multicenter, randomized, placebo-controlled Phase 2 study of adult patients with painful diabetic peripheral neuropathy (DPN), reported lead author Anne M. Calkins, MD, of New York Spine and Wellness Center, North Syracuse, NY, and colleagues at PAINWeek 2014. “The weight gain in GEn-treated patients appeared to be dose-dependent.”

The differences are clinically significant because they may improve patient tolerance and treatment adherence, the coauthors said.A total of 420 adult patients with type 1 or 2 diabetes mellitus with DPN-attributed painful distal symmetric sensorimotor polyneuropathy were randomly assigned to receive GEn 1200 mg/day, GEn 2400 mg/day, GEn 3600 mg/day, pregabalin 300 mg/day, or placebo, for 20 weeks.

Compared with pregabalin, patients administered gabapentin enacarbil experienced less peripheral edema and weight gain. Peripheral edema occurred in 11% of patients in the GEn 3600 mg and the pregabalin groups, 0% of the GEn 2400 mg-group patients, and 2% of GEn 1200 mg-group patients, and 5% of placebo-group patients, the authors reported.

Worsening grade in pedal edema relative to baseline occurred in 8% of patients in the placebo group, 11% of GEn 1200 mg, 16% of GEn 2400 mg, and 10% of GEn 3600 mg, compared to 28% of patients in the pregabalin.

Mean change from baseline for weight gain at week 13 or at last observation in early termination was -0.55 kg for placebo; +1.22 kg for GE 1200 mg; +1.71 kg GEn 2400 mg; +1.85 kg GEn 3600 mg; and +2.65 kg GEn pregabalin.

“Across treatment groups, the majority of patients reported at least one TEAE [treatment-emergent adverse event],” the coauthors noted. “The most common TEAEs that occurred in ≥5% of patients in either the GEn or pregabalin treatment groups included dizziness, somnolence, nausea, and peripheral edema. All of the most common TEAEs occurred more frequently in at least one active treatment arm than in the placebo arm.”

Gabapentin enacarbil has been approved by the FDA for postherpetic neuralgia in adults and moderate-to-severe primary restless legs syndrome; it is not approved for the treatment of DPN.