A double-blind, placebo-controlled, dose-response pilot study evaluating intradiscal etanercept in patients with chronic discogenic low back pain or lumbosacral radiculopathy.

BACKGROUND: In recent years, convincing evidence has emerged implicating tumor necrosis factor alpha as a causative factor in radiculopathy and discogenic back pain. But although preliminary open-label studies demonstrated promising results for the treatment of low back pain with tumor necrosis factor-alpha inhibitors, early optimism has been tainted by a controlled study showing no significant benefit in sciatica. To determine whether outcomes might be improved by a more direct route of administration, the authors evaluated escalating doses of intradiscal etanercept in 36 patients with chronic lumbosacral radiculopathy or discogenic low back pain.

METHODS: A double-blind, placebo-controlled pilot study was conducted whereby six patients received 0.1, 0.25, 0.5, 0.75, 1.0, or 1.5 mg etanercept intradiscally in each pain-generating disc. In each escalating dose group of six patients, one received placebo. A neurologic examination and postprocedure leukocyte counts were performed in all patients at 1-month follow-up visits. In patients who experienced significant improvement in pain scores and function, follow-up visits were conducted 3 and 6 months after the procedure.

RESULTS: At 1-month follow-up, no differences were found for pain scores or disability scores between or within groups for any dose range or subgroup of patients. Only eight patients remained in the study after 1 month and elected to forego further treatment. No complications were reported, and no differences were noted between preprocedure and postprocedure leukocyte counts.

CONCLUSIONS: Although no serious side effects were observed in this small study, a single low dose of intradiscal etanercept does not seem to be an effective treatment for chronic radicular or discogenic low back pain.