Statins can inhibit the beneficial effects of rituximab on disease activity in rheumatoid arthritis patients, according to the findings of a study of 187 patients from the Dutch Rheumatoid Arthritis Monitoring registry.
After 6 months of treatment, the mean reduction in disease activity score using 28 joint counts (DAS28) was lower in 23 of 187 RA patients who were treated with both statins and rituximab (RTX) than in 164 patients treated with RTX alone (mean reduction of 0.5 vs. 1.0 point). The difference was of borderline statistical significance after adjustment for age, sex, baseline DAS28 score, and rheumatoid factor positivity, Dr. E.E.A. Arts of Radboud University Nijmegen (the Netherlands) Medical Center and colleagues reported online in the Oct. 18 issue of Annals of the Rheumatic Diseases.
Compared with the RTX-only patients, those exposed to statins also had a shorter effective period following RTX treatment (median of 7 months vs. 9 months), and were more likely to experience a failure event (hazard ratio, 2.3), after adjustment for the same confounders, the investigators said (Ann. Rheum. Dis. 2010 Oct. 18 [doi:10.1136/ard.2010.136093]).
All patients in the DREAM registry were included in the prospective cohort study, and all received 50 mg of prednisone with the first RTX infusion. Patients in both the RTX plus statin and the RTX-only groups had similar DAS28 scores at baseline. The statin group was older (mean age, 66 vs. 58 years) and included a greater proportion of men than the RTX-only group (48% vs. 20%), but the groups were otherwise similar.
Although the study had a small sample size, it was sufficiently powered and showed a clinically relevant difference in DAS28 score changes over the 6-month study period, the investigators noted, adding that lack of randomization was another limitation of little concern, because "confounding by indication is unlikely."
More studies to replicate these findings and measure the magnitude of the effect are needed, they said.
"Significant interactions of statins with RTX in RA have not previously been shown. A critical review of common practice regarding concomitant use of statins in RTX-treated patients with RA is needed," they concluded.
The DREAM registry is funded by the Dutch affiliations of Wyeth Pharmaceuticals, Abbott Laboratories, Schering-Plough Corp., Roche Pharmaceuticals, UCB Pharma Inc., and Bristol-Myers Squibb Co.