medwireNews: A retrospective cohort study suggests significantly higher retention with methotrexate monotherapy than sulfasalazine in DMARD-naïve patients with psoriatic arthritis (PsA).
“While there is a lack of high-level evidence to support the use of cs [conventional synthetic] DMARD efficacy in PsA, csDMARD drug retention rates can provide indirect evidence,” say Emmerik Leijten (University Medical Center Utrecht, the Netherlands) and fellow researchers.
They therefore analyzed data pertaining to 184 individuals with PsA who received first-line methotrexate (n=163) or sulfasalazine (n=21) as a monotherapy.
The primary outcome of median time to csDMARD failure, defined as discontinuing the first-line csDMARD or adding another DMARD, was significantly longer for methotrexate than sulfasalazine, at 34.5 versus 12.0 months.
And at 12 months, 72% of patients who initiated methotrexate as their first-line treatment were still taking it as a monotherapy compared with 52% of those who initiated sulfasalazine.
Overall, the median duration of csDMARD drug retention was approximately 2.5 years, but Leijten et al highlight that “monotherapy drug retention shows a large drop in the first year of treatment” for all csDMARDs.
The main reasons for discontinuing methotrexate and sulfasalazine were inefficacy (49.5 vs 66.7%) and side effects (27.9 vs 22.2%). And the major side effects associated with treatment discontinuation were gastrointestinal complaints (35.5 vs 25.0%), malaise (25.8 vs 25.0%), and hepatotoxicity (22.6 vs 0.0%).
Of the patients receiving methotrexate, 9.9% discontinued treatment due to remission, as did 11.1% of those taking sulfasalazine. Some patients also discontinued due to (planned) pregnancy – all 6.3% of those who had been taking methotrexate.
The most common courses of action upon first-line methotrexate or sulfasalazine failure were switching to a different csDMARD (22.5 vs 55.6%), continuing treatment with the addition of a biologic DMARD (29.7 vs 0.0%), stopping treatment and not starting a new biologic or csDMARD (24.3 vs 16.7%), and continuing treatment with the addition of another csDMARD (9.0 vs 22.2%).
Writing in Rheumatology, the researchers draw attention to the study's limitations, emphasizing the small number of patients taking sulfasalazine and the use of an indirect measure of treatment efficacy.
Nevertheless, Leijten and colleagues believe that their findings “support the use of [methotrexate] as first-line therapy in treating peripheral arthritis in PsA, as recommended by current EULAR and GRAPPA guidelines.”
And they add: “Future prospective studies should further elucidate the efficacy of csDMARDs as first-line treatment for PsA.”
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