Study of the Safety and Efficacy of RGH-896 in Patients With Diabetic Peripheral Neuropathic Pain

Inclusion Criteria: * Male or female outpatients 18 to 75 years of age * A diagnosis of painful diabetic neuropathy * Controlled blood glucose * Willingness to wash out all analgesic medications used for DPNP * Female patients either postmenopausal, surgically sterile, or practicing a medically acceptable method of contraception * Female patients who are not pregnant Exclusion Criteria: * Acute infections or cardiac problems * Past use of pregabalin * History of severe psychiatric disorder * History of any amputation due to diabetes * History of seizure disorder * Active diabetic foot ulcers