Comparison of Efficacy of Ixekizumab and Adalimumab in Patients with Psoriatic Arthritis and Moderate to Severe Psoriasis

Study Methodology and Course

The open-label randomized SPIRIT-H2H study with a blinded assessor included a total of 565 patients with active psoriatic arthritis (defined as ≥ 3 tender and swollen joints) and plaque psoriasis affecting ≥ 3% of the body surface area, who had not previously been treated with biological disease-modifying antirheumatic drugs (bDMARDs). Participants were randomized into two groups: the first (n = 283) was treated with ixekizumab, the second (n = 282) with adalimumab, a human monoclonal antibody inhibiting tumor necrosis factor alpha (TNF-α).

The primary endpoint of the study was the improvement of ≥ 50% according to American College of Rheumatology criteria (ACR50) concurrently with a 100% improvement in PASI score (PASI 100) after 24 weeks of treatment with ixekizumab or adalimumab. We summarized the study results (Mease et al.) shortly after their first publication here.

Analyzed Subpopulation

A total of 49 patients treated with ixekizumab (mean age 45.3 years; 61.2% male) and 51 patients treated with adalimumab (mean age 46.3 years; 64.7% male) had active psoriatic arthritis and concurrent moderate to severe psoriasis (defined as Psoriasis Area and Severity Index [PASI] score ≥ 12; static Physician Global Assessment [sPGA] score ≥ 3 and ≥ 10% body surface area involvement). The mean PASI score was 22, and approximately 50% of patients in both groups additionally used methotrexate.

Both drugs were dosed in-label for this subpopulation: the initial dose of ixekizumab was 160 mg, followed by 80 mg every 2 weeks until week 12, and then the same dose every 4 weeks until week 24. The initial dose of adalimumab was 80 mg, followed by 40 mg a week later, then 40 mg every 2 weeks until week 24.

Study Goals and Results

Among patients with active PsA and moderate to severe psoriasis treated with ixekizumab, 20 out of 49 (40.8%) achieved both ACR50 and PASI 100 after 24 weeks. In the group treated with adalimumab, this improvement was observed in 9 out of 51 patients (17.6%; p < 0.05). This trend was significant from week 8 of treatment. Significantly more patients treated with ixekizumab achieved PASI improvement of 75/90/100% at week 24 compared to adalimumab. This trend was significant from week 4 of treatment.

Conclusion

A significantly higher proportion of patients with active psoriatic arthritis and moderate to severe psoriasis showed superior joint and skin improvements (ACR50 and PASI 100) as well as skin improvements (PASI 75/90/100) after 24 weeks of treatment with ixekizumab compared to adalimumab.

(mafi)

Sources:
1. Reich K., Gooderham M., Kristensen L. E. et al. P1765: Efficacy of ixekizumab versus adalimumab in psoriatic arthritis patients with moderate-to-severe psoriasis: 24-week results from a multicenter, randomized study. European Academy of Dermatology and Venereology (EADV), Madrid, 2019 Oct 12.
2. Mease P. J., Smolen J. S., Behrens F. et al. A head-to-head comparison of the efficacy and safety of ixekizumab and adalimumab in biological-naïve patients with active psoriatic arthritis: 24-week results of a randomized, open-label, blinded-assessor trial. Ann Rheum Dis 2020; 79: 123–131, doi: 10.1136/annrheumdis-2019-215386.