Background Based on several experimental results and on a preliminary study, a trial was undertaken to assess the efficacy of adalimumab, a TNF-α inhibitor, in patients with radicular pain due to lumbar disc herniation.
Methods A multicentre, double-blind, randomised controlled trial was conducted between May 2005 and December 2007 in Switzerland. Patients with acute (< 12 weeks) and severe (Oswestry Disability index > 50) radicular leg pain and imaging-confirmed lumbar disc herniation were randomised to receive as adjuvant therapy either two subcutaneous injections of adalimumab (40 mg) at 7 days interval or matching placebo. The primary outcome was leg pain, which was recorded every day for 10 days and at 6-weeks and 6- months based on a visual analogue scale (0 to 100).
Results Of the 265 patients screened, 61 were enrolled (adalimumab= 31) and 4 were lost to follow-up. Over time, the evolution of leg pain was more favourable in the adalimumab group than in the placebo group (p<0.001). However, the effect size was relatively small and at last follow-up the difference was 13.8 (CI95% -11.5 - 39.0). In the adalimumab group twice as many patients fulfilled the criteria for "responders" and for "low residual disease impact" ( p<0.05) and fewer surgical discectomies were performed (6 versus 13, p=0.04).
Conclusion The addition of a short course of adalimumab to the treatment regimen of patients suffering from acute and severe sciatica resulted in a small decrease in leg pain and in significantly fewer surgical procedures.