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07-02-2019 | Psoriatic arthritis | News

Ixekizumab treatment linked to enthesitis, dactylitis improvements in PsA

medwireNews: A post-hoc analysis of the SPIRIT-P1 and SPIRIT-P2 trials suggests that treatment with ixekizumab is associated with improvements in enthesitis and dactylitis among patients with psoriatic arthritis (PsA).

The analysis included 679 trial participants who were treated with the interleukin (IL)-17A inhibitor, at a dose of 80 mg every 2 or 4 weeks after a starting dose of 160 mg, or placebo. In all, 403 patients had enthesitis (Leeds Enthesitis Index [LEI] score >0 points) at baseline, while 155 had dactylitis (Leeds Dactylitis Index-Basic [LDI-B] score >0 points).

As reported in Arthritis Research & Therapy, a significantly higher proportion of patients treated with ixekizumab every 2 or 4 weeks experienced resolution of enthesitis – defined as a LEI score of 0 points – by week 24 than those given placebo, with rates of 35% and 39% versus 21%, respectively.

Similarly, rates of dactylitis resolution, indicated by an LDI-B score of 0 points, were significantly higher among patients in the ixekizumab versus placebo groups, at a corresponding 65% and 78% versus 24%.

Dafna Gladman (University of Toronto, Ontario, Canada) and co-investigators say that resolution of enthesitis was associated with improvement in health-related quality of life and functioning, irrespective of treatment group, but dactylitis resolution was associated with more modest improvements.

“The ability to see an association of improvement in physical functioning and quality of life with dactylitis resolution may be limited due to the smaller numbers of patients with dactylitis than enthesitis,” remark the researchers.

The least squares (LS) mean decrease in HAQ-DI score from baseline to week 24 was 0.44 points for patients with enthesitis resolution compared with 0.25 points for those without, and the LS mean improvement in the EuroQol-5 Dimensions Visual Analogue Scale (EQ-5D) score was 12.3 versus 5.8 points.

Participants with enthesitis resolution were also more likely than those without to achieve the minimal clinically important difference (MCID) in HAQ-DI score of 0.35 points over 24 weeks, with 62% and 28%, respectively, meeting this endpoint.

Patients with and without dactylitis resolution had an LS mean decrease in HAQ-DI score of 0.41 and 0.31, respectively, and the improvements in EQ-5D score were 10.8 and 9.8 points, respectively. In all, 68% of patients with dactylitis resolution and 21% of those without achieved the MCID in HAQ-DI score.

Together, “these results indicate that ixekizumab is effective for the treatment of enthesitis and dactylitis,” write the researchers.

They note, however, that “the SPIRIT studies were not designed to evaluate enthesitis and dactylitis as primary endpoints.”

By Claire Barnard

medwireNews is an independent medical news service provided by Springer Healthcare. © 2019 Springer Healthcare part of the Springer Nature group

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