Expert opinion on emerging drugs: chronic low back pain

Introduction: It is difficult to overestimate the personal and socioeconomic impact of chronic low back pain (CLBP). It is the leading cause of years lost to disability and poses the highest economic toll among chronic illnesses. Despite the strong need for extensive research efforts, few drugs have consistently demonstrated effectiveness for this condition. Areas covered: In this review, the epidemiology, rationale for mechanismbased treatment, competitive environment and market trends, and the preclinical and clinical evidence supporting over 15 different classes of analgesic medications studied for CLBP or related pain conditions are discussed. Treatments are divided by drug category, type of CLBP they are likely to treat (e.g., neuropathic or mechanical), and whether they are new formulations of existing treatments, new indications for existing treatments or represent novel mechanisms of action. Databases searched included MEDLINE, Embase, Pharmaprojects and various clinical trial registries. Expert opinion: Many barriers exist for the development of medications for CLBP including difficulties in identifying pathophysiological mechanisms, biologic resiliency secondary to multiple concurrent pain pathways and offtarget and sometimes serious side effects. Nevertheless, the volume and diversity of novel molecular entities has continued to surge and includes possible disease-modifying therapies such as gene and stem cell therapy.