Anti-TNF therapy fails to relieve pain caused by hand osteoarthritis, study suggests

Osteoarthritis, or OA as it is commonly called, is the most common joint disease affecting middle-age and older people. It is characterized by progressive damage to the joint cartilage -- the cushioning material at the end of long bones. It can causes changes in the structures around the joint including fluid accumulation, bony overgrowth, and weakness of muscles and tendons, all of which may limit movement and cause pain and swelling.

People with hand osteoarthritis often experience pain in multiple joints and previous studies have documented that the disease does not respond to several of the traditional therapies used in its treatment. However, anti-TNF medications may represent a real hope, because TNF is a molecule found to contribute to the destruction of cartilage and inflammation of joints. Researchers on behalf of the French National Section on OA (led by the Hopital Henri Mondor ) in France recently compared the effectiveness of TNF blockers (commonly called anti-TNFs) and nonsteroidal anti-inflammatory drugs (also called NSAIDs) in controlling pain in people with hand OA.

The digital osteoarthritis in refractory hand OA study (called DORA) included hand OA patients who did not respond to painkillers and NSAIDs. Patients also had to meet the American College of Rheumatology criteria for hand OA with significant pain, at least three painful inter phalangeal hand joints and a minimum of three involved joints identified by X-ray. The study was conducted at 16 different clinical sites. Eighty-five patients were randomly divided into two groups. One group received adalimumab (Humira®), and the other group received placebo. Neither the patients nor the researchers were told who was in which group. Patients were monitored for 26 weeks. Those in the adalimumab group received two injections of the therapy at the beginning and second week of the trial.

Researchers established that a change of more than 50 percent in improvement in pain score after six weeks would be considered therapeutic success. Additional signs of success after six weeks included fewer painful and swollen joints, decreased morning stiffness and improved patient and practitioner assessments. Researchers monitored use of painkillers (acetaminophen up to three grams daily was the only medication allowed until week six) and the progression of the disease using blood and urine tests.

Of the 85 patients (42 in the placebo group, 41 in the adalimumab group), 35 in the placebo group and 38 in the adalimumab group received the two injections. Seventy-eight patients with at least one injection were analyzed (37 placebo and 41 adalimumab). The mean age of the patients was 62.5 years; 85 percent were women. Mean pain level at study beginning was 65.4 millimeters on a zero to 100 mm scale; and patients had a mean of 11 painful joints, and 5.9 clinically inflamed digital joints.

After six weeks of receiving adalimumab and placebo, researchers measured only a 2.5 millimeter difference in the average change in pain score between the groups. At week six, there was no difference between groups on the main outcome -- where they measured 50 percent improvement (35.1 percent in the adalimumab group versus 27.3 percent in the placebo group). The only difference recorded was a decrease in the number of swollen joints between week zero and week 26 in the adalimumab group. No other significant changes or concerns were reported.

"Our research found that two injections of anti-TNF failed to improve severe painful hand OA," says Xavier Chevalier, MD, PhD, head of the department of rheumatology at Hopital Henri Mondor in France and lead investigator of the study. "New trials are needed to find the right target in painful hand OA because this is a disease where we have no real therapy and the patients develop the feeling of a neglected disease."

Patients should talk to their rheumatologists to determine their best course of treatment.

This study was promoted by the APHP clinical research and osteoarthritis group of the French Society, and funding from Inserm pro A and a grant from ABBOTT laboratory.