Additional rituximab dose can improve response to treatment in rheumatoid arthritis

People with rheumatoid arthritis who are treated with rituximab could sometimes benefit from an extra dose of the drug if they seem to be responding poorly, says research published in the Annals of the Rheumatic Diseases.

Rituximab usually works by lowering the number of circulating B cells in the blood. But if the drug doesn’t manage to lower the B cells enough, its benefits are undermined.

So a group of scientists looked at people who had active rheumatoid arthritis even though they took methotrexate. They were given a standard does of 1,000mg infusion of rituximab and then tested for B cells on day 15. Everyone received a second 1,000mg infusion as normal. But some still had persistently high B cell counts, so half of this group were given a third dose two weeks later, while others received a placebo.

Those given the extra dose experienced significantly greater B cell depletion, which made the treatment more effective.

“An extra 1,000 mg infusion of rituximab at four weeks produced both better depletion and clinical responses than placebo with no worsening of safety,” the scientists say. “Degree of depletion is an important, but modifiable, determinant of response.”

To read the original research visit: http://ard.bmj.com/content/early/2014/01/17/annrheumdis-2013-204544.abstract?sid=67ca6535-6a03-44fd-86ca-ff936e2edbf8