Lilly Announces Long-Term Results from Head-to-Head SPIRIT-H2H Trial of Taltz (ixekizumab) Versus Humira in Biologic-Naïve Patients with Active Psoriatic Arthritis

Compiled by S.Li

On June 3 local time, Eli Lilly announced the results of the SPIRIT-H2H subgroup analysis from the Phase 3b/4 SPIRIT clinical trial evaluating the IL-17A antagonist Taltz (ixekizumab). This 52-week, head-to-head study compared Taltz with Humira (adalimumab) in patients with active psoriatic arthritis (PsA) who were naïve to biologic therapy. The results demonstrated that Taltz, either as monotherapy or in combination with methotrexate (MTX) or other csDMARDs (conventional synthetic disease-modifying antirheumatic drugs), achieved significant efficacy and overall showed superiority over Humira. The latest data from this study will be presented at the European Congress of Rheumatology on June 5.

SPIRIT-H2H is the first superiority study versus Humira in patients with psoriatic arthritis (PsA), with the primary endpoint being the simultaneous achievement of ACR50 (as defined by the American College of Rheumatology, indicating at least a 50% reduction in disease activity) and PASI 100 (a 100% improvement in the Psoriasis Area and Severity Index) at Week 24.

In this prespecified analysis, the efficacy at Week 52 was compared across three subgroups: monotherapy with Taltz or Humira, Taltz or Humira in combination with methotrexate (MTX), and Taltz or Humira in combination with MTX and conventional synthetic disease-modifying antirheumatic drugs (csDMARDs). The results at Week 52 demonstrated that improvements were observed in multiple study endpoints in the Taltz treatment groups, regardless of the concomitant use of MTX or other csDMARDs.

In the monotherapy subgroup, a higher proportion of patients treated with Taltz achieved minimal disease activity (MDA) compared with Humira (49% vs. 33%); in the subgroup concomitantly using methotrexate (MTX), response rates were similar between the Taltz and Humira groups (47% vs. 47%); when used in combination with conventional synthetic disease-modifying antirheumatic drugs (csDMARDs), the proportions of patients achieving MDA were also similar (47% vs. 44%).

At Week 52, a higher proportion of patients treated with Taltz achieved the primary endpoint (i.e., simultaneous achievement of ACR50 and PASI 100) across all three subgroups. The proportions of patients achieving the primary endpoint in each subgroup were as follows:

Monotherapy: Taltz 38%, Humira 19%;

Concomitant use with MTX: Taltz 39%, Humira 30%;

Concomitant use of csDMARDs: Taltz 40%, Humira 29%.

In addition to the SPIRIT-H2H subgroup study, Eli Lilly also disclosed significant findings from two other studies of Taltz. In the SPIRIT-P2 study, patients who had an inadequate response or intolerance to one or two tumor necrosis factor inhibitors (TNFi) experienced sustained improvements for up to three years with Taltz treatment in terms of ACR response measures, signs and symptoms of psoriatic arthritis (PsA), and PsA manifestations (including enthesitis, dactylitis, and skin outcomes). In the Phase 3 COAST-X clinical trial conducted in patients with active non-radiographic axial spondyloarthritis (nr-axSpA), those receiving Taltz showed improvements in fatigue, spinal pain, and stiffness by Week 16.

Reference Source: EULAR 2020: Lilly's Taltz® (ixekizumab) Continues to Show Robust and Consistent Efficacy in Psoriatic Arthritis