NEW YORK (Reuters Health) – The TNF alpha inhibitor adalimumab provides minor analgesia in patients with radicular pain due to lumbar disc herniation, but prompts a major reduction in the need for surgery, Swiss researchers report in an April 6th online paper in Arthritis and Rheumatism.

“Our study showed that a short course of adalimumab had a modest effect on pain, but had an important impact by reducing the number of surgeries,” lead author Dr. Stephane Genevay told Reuters Health by email.

Dr. Genevay and colleagues at University Hospitals of Geneva analyzed data on 57 patients with acute and severe radicular leg pain and imaging-confirmed lumbar disc herniation.

The patients participated in a randomized trial comparing adalimumab (2 injections of 40 mg, 7 days apart) to placebo. Leg pain and lower back pain were assessed daily for 10 days and then at 6 weeks and at 6 months, using a visual 100-point analogue scale.

The evolution of leg pain was significantly different between the groups, in favor of adalimumab (p < 0.0001), but the absolute differences in leg pain at any point were small and were significant only for two days after treatment initiation, according to the report.

The overall mean pain score at day 10 was 38.3 in the adalimumab patients and 44.3 in the placebo group. At 6 months, overall mean pain scores were 16.1 with adalimumab and 29.2 with placebo.

In the absence of surgery, 70% of treated patients and 43% of the placebo group had at least a 30% reduction in the pain score.

The evolution of back pain was also significantly different between the two groups, in favor of adalimumab, with significant differences at most time points. At 6 months, 65% of the patients in the adalimumab group met the criteria for back pain response versus 27% in the placebo group.

No patients required surgery in the first 10 days. One patient in the adalimumab group and 5 in the placebo group had surgery by week 6. By 6 months, 6 adalimumab patients and 13 placebo patients had undergone surgery.

The authors say that “for every 4.17 patients treated with adalimumab, one surgery will be prevented.”

The results “confirm the role of TNF alpha in the pathophysiology of sciatica,” Dr. Genevay said, although “the exact dose and route of administration of TNF inhibitors (must) be determined before clinical use.”

Arthritis Rheum 2010.