Arthritis drug unlikely to slow spinal arthritis

In people with a type of arthritis affecting the spine called ankylosing spondylitis, treatment with infliximab (Remicade) and other so-called “TNF-blockers” yields significant benefits in terms of symptoms, physical functioning and quality of life, although these drugs are unlikely to inhibit structural damage, according to a new study by European and US doctors.

“Although disappointing, it is not unexpected,” Dr. Désirée van der Heijde told Reuters Health, that infliximab did not inhibit the formation of new abnormal bone growth on the spine in this study as another TNF-blocker, etanercept (Enbrel), also did not inhibit this.

van der Heijde of Leiden University Medical Center, The Netherlands, and colleagues examined x-ray data on 201 patients with ankylosing spondylitis who were treated with infliximab treatment over a period of 96 weeks.

Comparison of findings at the start of the study and at 2 years showed no changes in patients’ spinal condition, the researchers report in the journal Arthritis and Rheumatism. This was also true of a group of “historical” controls with ankylosing spondylitis who had not been treated with TNF-blockers.

The proportion of patients with at least a 1-point worsening in their condition, based on a standard index, was virtually the same in both treated and untreated cohorts - 34 percent and 35 percent, respectively.

Ankylosing spondylitis resembles arthritis, but the chronic inflammation is confined mainly to the spine and can lead to actual fusion of the joints.

A possible explanation for the lack of an effect on progression, the researchers suggest, is that bone formation is the hallmark of ankylosing spondylitis, rather the proinflammatory action of TNF in predominantly destructive diseases like rheumatoid arthritis.

“On the other hand,” concluded van der Heijde, “it is still very useful to prescribe TNF-blockers to patients with ankylosing spondylitis as these drugs have a major positive effect on signs and symptoms, physical function, and quality of life.”

SOURCE: Arthritis and Rheumatism, October 2008.