RESEARCH - Rituximab retreatment unsuccessful in RA after first course fails

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Rituximab Retreatment Unsuccessful in RA After First Course Fails

NEW YORK (Reuters Health) Dec 25 - Rituximab treatment will likely

fail again if the initial course is unsuccessful in patients with

rheumatoid arthritis, Dutch researchers report in the December issue

of Arthritis & Rheumatism.

In a study led by Dr. Rogier M. Thurlings of the University of

Amsterdam, 30 patients with Disease Activity Scores in 28 joints

(DAS28) of 3.2 or greater received up to three courses of rituximab

treatment administered at intervals of at least 6 months, regardless

of the initial treatment response.

Of the 26 patients available for evaluation after 6 months, 18

qualified for retreatment because of continued disease activity. Six

patients were retreated later after disease relapse. Two patients had

low disease activity and were not retreated.

Seven of 24 patients who qualified for retreatment failed to respond

to the initial course of rituximab.

" These patients typically did not respond to subsequent courses of

rituximab, " Dr. Thurlings and colleagues report.

Seventeen patients responded to the first course of rituximab,

according to European League Against Rheumatism (EULAR) criteria.

These patients had similar responses on their second and third

treatment courses, without major disease relapse before the next round

of treatment was scheduled.

Patients who do not respond to rituximab may " represent a different

pathogenetic subset of RA, " the researchers suggest. " Perhaps RA is

not a single pathogenetic entity, but comprises different subsets

leading to similar common final pathways. "

Dr. Thurlings' team proposes several possible explanations to account

for variations in treatment response. " Disease mechanisms independent

of B cells might be driving synovial inflammation in patients not

responding to rituximab treatment, " they continue. " It is also

conceivable that B cell proliferation and plasma cell formation may

continue to occur despite treatment with anti-CD20 antibodies. "

The bottom line is the same, Dr. Thurlings and colleagues conclude:

" Rituximab retreatment is not effective in patients who do not exhibit

clinical improvement after the first treatment course. "

Arthritis Rheum 2008;58:3657-3664.

http://www.medscape.com/viewarticle/585927

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