The purpose of this study is to determine the effectiveness and safety of the investigational drug, tanezumab, in adult patients with painful diabetic peripheral neuropathy.
Inclusion Criteria: * Diagnosis of diabetes mellitus (high blood sugar) with HbA1c levels of ≤11% at Screening, and on a stable anti-diabetic medication regimen for the 30 days prior to randomization. * Diagnosis of diabetic peripheral neuropathy pain in the legs or feet with decreased sensation in the feet or decreased/absent ankle jerk/ reflexes. * Presence of ongoing pain due to diabetic peripheral neuropathy for at least 3 months. * A pain score of greater than or equal to (≥) 4 for from diabetic peripheral neuropathy on the Numerical Rating Scale (NRS), a 11-point scale with 0 meaning no pain and 10 meaning worst pain at Screening. * Be willing to stop all pain medications for diabetic peripheral neuropathy except for the limited use of acetaminophen (Tylenol) or ibuprofen-like (Motrin) medications between Screening and Baseline and not use prohibited pain medications throughout the duration of the study except as permitted by the study guidelines. Exclusion Criteria: * Painful neuropathies other than diabetic peripheral neuropathy. * Other types of diabetic neuropathies. * Patients with a past history of carpal tunnel syndrome (CTS) with signs or symptoms of CTS in the one year prior to Screening are not eligible for participation. * Patients with fibromyalgia, regional pain caused by lumbar or cervical compression with radiculopathy or other moderate to severe pain. * Patients with a present (current) history of sciatica are not eligible for participation. * The presence of pain conditions that cannot be distinguished from diabetic peripheral neuropathy such as peripheral vascular disease. * Amputations dues to diabetes. * Patient with any clinically significant medical condition or laboratory abnormalities. * History, diagnosis, or signs and symptoms of clinically significant neurological diseases (such as Alzheimer's disease, head trauma, epilepsy or stroke). * History, diagnosis, or signs and symptoms of clinically significant psychiatric diseases (such as bipoar disorder or schizophrenia). * History of known alcohol, analgesic or drug abuse within 2 years of Screening. * Pregnant women, lactating mothers, women suspected of being pregnant, and women who wish to be pregnant during the course of clinical study.