The purpose of this study is to evaluate the safety and effectiveness of an investigational medication for chronic low back pain that may radiate into one or both legs. The study begins with a screening period to determine eligibility, followed by three treatment phases. During the first phase, eligible participants will be randomly assigned to receive one of two doses of the investigational medication or a placebo (an inactive treatment). All study-related treatments, evaluations, and diagnostic procedures are provided at no cost to you or your insurance. By participating, you may contribute to research aimed at developing new treatment options for individuals living with chronic low back pain.