Ixekizumab for the treatment of patients with active psoriatic arthritis and an inadequate response to tumour necrosis factor inhibitors: results from the 24-week randomised, double-blind, placebo-controlled period of the SPIRIT-P2 phase 3 trial.

BACKGROUND: Patients who have had inadequate response to tumour necrosis factor inhibitors have fewer treatment options and are generally more treatment refractory to subsequent therapeutic interventions than previously untreated patients. We report the efficacy and safety of ixekizumab, a monoclonal antibody that selectively targets interleukin-17A, in patients with active psoriatic arthritis and previous inadequate response to tumour necrosis factor inhibitors. METHODS: In this double-blind, multicentre, randomised, placebo-controlled, phase 3 study (SPIRIT-P2), patients were recruited from 109 centres across ten countries in Asia, Australia, Europe, and North America. Patients were aged 18 years or older, had a confirmed diagnosis of psoriatic arthritis for at least 6 months, and had a previous inadequate response, distinguished by being refractory to therapy or had loss of efficacy, or were intolerant to tumour necrosis factor inhibitors. Patients were randomly assigned (1:1:1) by a computer-generated random sequence to receive a subcutaneous injection of 80 mg ixekizumab every 4 weeks or every 2 weeks after a 160 mg starting dose or placebo. The primary endpoint was the proportion of patients who attained at least 20% improvement in the American College of Rheumatology response criteria (ACR-20) at week 24. This study is registered with ClinicalTrials.gov, number NCT02349295. FINDINGS: Between March 3, 2015, to March 22, 2016, 363 patients were randomly assigned to placebo (n=118), ixekizumab every 4 weeks (n=122), or ixekizumab every 2 weeks (n=123). At week 24, a higher proportion of patients attained ACR-20 with ixekizumab every 4 weeks (65 [53%] patients; effect size vs placebo 33·8% [95% CI 22·4-45·2]; p<0·0001) and ixekizumab every 2 weeks (59 [48%] patients; 28.5% [17·1-39.8]; p<0·0001) than did patients with placebo (23 [20%] patients). Up to week 24, serious adverse events were reported in three (3%) patients with ixekizumab every 4 weeks, eight (7%) with ixekizumab every 2 weeks, and four (3%) with placebo; no deaths were reported. Infections were reported in 47 (39%) patients with ixekizumab every 4 weeks, 47 (38%) with ixekizumab every 2 weeks, and 35 (30%) with placebo. Three (2%) serious infections, all in patients in the ixekizumab every 2 weeks group, were reported. INTERPRETATION: Both the 2-week and 4-week ixekizumab dosing regimens improved the signs and symptoms of patients with active psoriatic arthritis and who had previously inadequate response to tumour necrosis factor inhibitors, with a safety profile consistent with previous studies investigating ixekizumab. FUNDING: Eli Lilly and Company.

Safety and efficacy of ixekizumab in patients with PsA and previous inadequate response to TNF inhibitors: week 52 results from SPIRIT-P2.

Objectives: To assess the long-term safety and efficacy of ixekizumab, an IL-17A antagonist, in patients with active PsA. Methods: In SPIRIT-P2 (NCT02349295), patients (n = 363) with previous inadequate response to TNF inhibitors entered the double-blind period (weeks 0-24) and received placebo or ixekizumab 80 mg every 4 weeks (IXEQ4W) or every 2 weeks (IXEQ2W) following a 160-mg starting dose at week 0. During the extension period (weeks 24-156), patients maintained their original ixekizumab dose, and placebo patients received IXEQ4W or IXEQ2W (1:1). We present the accumulated safety findings (week 24 up to 156) at the time of this analysis for patients who entered the extension period (n = 310). Exposure-adjusted incidence rates (IRs) per 100 patient years are presented. ACR responses are presented on an intent-to-treat basis using non-responder imputation up to week 52. Results: From week 24 up to 156 (with 228 patient years of ixekizumab exposure), 140 [61.3 IR] and 15 (6.6 IR) patients reported infections and serious adverse events, respectively. Serious adverse events included one death and four serious infections. In all patients initially treated with IXEQ4W and IXEQ2W at week 0 (non-responder imputation), ACR20 (61 and 51%), ACR50 (42 and 33%) and ACR70 (26 and 18%) responses persisted out to week 52. Placebo patients re-randomized to ixekizumab demonstrated efficacy as measured by ACR responses at week 52. Conclusion: During the extension period, the overall safety profile of ixekizumab remained consistent with that observed with the double-blind period, and clinical improvements persisted up to 1 year.