麻豆传媒

WASHINGTON -- Most rheumatoid arthritis patients with established disease who achieve a state of low disease activity while taking etanercept (Enbrel) fare better if they remain on therapy, even if only at a lower dose, a researcher reported here.

Among patients whose disease activity scores were below 3.2 while on 50 mg etanercept a week, 52% who continued on that dosage maintained low disease activity at 2 years compared with only 13% of those who switched to placebo (OR 7.2, 95% CI 1.7 to 29.8, P=0.007), according to Ronald van Vollenhoven, MD, PhD, of the Karolinska Institute in Stockholm, and colleagues.

In addition, among those who switched to 25 mg of etanercept weekly, 44% continued to have low disease activity for 2 years (OR 4.2, 95% CI 1 to 17, P=0.044), van Vollenhoven reported at the annual meeting of the American College of Rheumatology.

The difference between the two active treatment groups was not statistically significant, but the study was not powered to assess this, he noted.

"The tradition we've had in treating rheumatoid arthritis is that if a medication works, you continue with that treatment. However, some people have rightly asked if this is necessary, and some small studies have suggested that it might be possible, at least in early disease, to stop treatment or lower the dosage," van Vollenhoven said.

"But the usual scenario with biologic treatment is for patients with longstanding, more severe disease, so we asked the question if this would be possible for patients with established disease," he said.

To address this, van Vollenhoven and his colleagues conducted a randomized trial that included 73 patients whose disease duration was 11 to 16 years and who had been on etanercept for 3 to 4 years with stable background doses of methotrexate.

Three-quarters were women, and mean age was 55. All had maintained disease activity scores in 28 joints (DAS28) below 3.2 for at least 11 months and, in fact, 80% were in clinical remission, with DAS28 scores below 2.6.

After 2 months of observation, to ensure that disease remained stable, patients were randomized to remain on 50 mg etanercept a week, to the reduced 25-mg dose, or placebo.

Failure was defined as a rise in the DAS28 to 3.2 or above or by an increase of 0.6 points. A subjective patient report of disease worsening also was considered failure.

Flares among the placebo group occurred quickly, usually within 4 to 6 weeks. In contrast, patients who worsened while remaining on treatment tended to flare a various times throughout the study.

"An important question is, are we putting the patient at risk if they are doing well on a treatment and we stop it or reduce the dose? Are we taking the chance that they will flare and we won't be able to recapture the favorable disease state? Thankfully, all the patients who were then retreated returned to low disease activity very quickly," he said.

A limitation of the study was the finding that more patients on the active treatment flared than was expected.

"We may have set the threshold too low for failure," van Vollenhoven said.

They also have not yet analyzed radiographic data for these patients.

"In conclusion, I believe that the aggregate of these data suggest that an induction-maintenance approach may be possible for patients with longstanding rheumatoid arthritis who have low disease activity and stable doses of methotrexate," he stated.

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