Ixekizumab Is Effective in Patients With Psoriatic Arthritis Regardless of Psoriasis Severity

Treatment with ixekizumab led to rapid improvements in joint, skin, and nail symptoms for patients with psoriatic arthritis, according to a post hoc analysis of the SPIRIT-P1 and SPIRIT-P2 trials. Benefits of treatment were seen regardless of psoriasis severity. These findings were published in Dermatology and Therapy.

The SPIRIT-P1 and SPIRIT-P2 trials evaluated ixekizumab, a selective interleukin-17A antagonist, versus placebo in patients with psoriatic arthritis and plaque psoriasis. For this post hoc analysis, the researchers evaluated musculoskeletal, skin, and nail outcomes through week 24. The study pooled 655 patients across both trials who were randomized to either ixekizumab (80 mg) or placebo every 4 weeks or every 2 weeks. The primary outcomes were the proportion of patients who achieved American College of Rheumatology (ACR)20, ACR50, and ACR70 responses. At baseline, 38.6% of patients had mild psoriasis, 31.8% had moderate psoriasis, and 29.6% had severe psoriasis.

Across all severity subgroups, a similar number of patients achieved ACR20/50/70 responses. More than one-third of patients treated with ixekizumab achieved ACR20 by week 4 and ACR50 at week 24, regardless of baseline psoriasis severity. Improvements in disease activity were similar in patients who received ixekizumab every 2 or 4 weeks. At 24 weeks, there was no difference in the proportion of patients who achieved minimal disease activity after ixekizumab therapy between psoriasis severity subgroups.

One-third of patients treated with ixekizumab achieved total skin clearance at week 24. “There was overall consistency observed between nail and skin outcomes in patients regardless of baseline psoriasis severity,” the authors wrote.

Both dosing regimens for ixekizumab “showed rapid and consistent efficacy across multiple disease activity measures, regardless of psoriasis severity at baseline,” the authors summarized.