An Evaluation of the Efficacy and Safety of E2007 in Patients With Painful Diabetic Neuropathy

Placebo tablets, once daily, for 15 weeks (taken orally).

Perampanel, 2 mg once daily, for 15 weeks (taken orally).

Perampanel, 2 mg once daily for three weeks, followed by 4 mg, once daily, for 12 weeks (taken orally).

Perampanel, 2 mg once daily for three weeks, followed by 4 mg once daily, for three weeks and 6 mg, once daily, for nine weeks (taken orally).

Perampanel, 2 mg once daily, for three weeks, followed by 4 mg, once daily for three weeks, 6 mg once daily for three weeks and 8 mg, once daily, for six weeks (taken orally).