One-year results from a head-to-head trial comparing ixekizumab (Taltz) and adalimumab (Humira) in patients with active PsA will help clinicians make evidence based treatment decisions, researchers say.
The phase IIIb/IV multicentre SPIRIT-H2H trial included 566 patients who were randomised to receive the interleukin 17A targeted antibody ixekizumab (n=246) or TNF inhibitor adalimumab (n=237). Patients received approved label dosing based on the presence or absence of moderate-to-severe psoriasis and were also permitted to continue taking csDMARDs.
As previously reported, at week 24 ixekizumab was shown to be superior to adalimumab for simultaneous achievement of American College of Rheumatology (ACR)50 and Psoriasis Area and Severity Index (PASI) 100 responses along with non-inferiority for ACR50 and superiority for PASI 100 achievement.
The current results published in the Annals of the Rheumatic Diseases found that benefit was maintained at one year, with significantly higher simultaneous ACR50 and PASI100 (64.3% vs 41.3%; p≤0.001) responses as well as PASI75 (78.4% vs 68.6%; p=0.008), PASI90 (72.8% vs 54.1%; p≤0.001) with ixekizumab than adalimumab.
Treatment with ixekizumab and adalimumab resulted in similar response rates for ACR50 (49.8% vs 49.8%), ACR20 (69.6% vs 68.9%) and ACR70 (35.3% vs 34.3%).
No new safety findings were reported for either ixekizumab or adalimumab.
Response rates for ixekizumab were consistent irrespective of concomitant csDMARD use, while numerically higher response rates for ADA were seen when used in combination with csDMARDs than in monotherapy.
The researchers, led by Josef Smolen from the Medical University of Vienna, Austria, noted that they did not measure antidrug antibodies to ixekizumab or adalimumab, which they said would have given insight into possible explanations for the differing impact of concomitant csDMARDs.
Limitations of the current study included its open label design, which the research team said may have contributed to outcome assessment bias, despite efforts to minimise this by using blinded assessors for key outcomes.
“On the other hand, open-label design better represents a real-world clinical setting where patients are aware of the treatment assignment,” they added.
“SPIRIT-H2H study comparing ixekizumab versus adalimumab is the first fully disclosed direct head-to-head study in PsA; its findings over 52 weeks will inform future treatment recommendations and may impact selection of therapy in bionaïve patients with active PsA,” the authors concluded.
The study was funded by Eli Lilly, manufacturer of ixekizumab (Taltz).