FUTURE 4 is a multicenter, randomized, double-blind, parallel-group, placebo-controlled 2-year study (104 weeks), conducted at 58 centers in 13 countries (Australia, Belgium, Bulgaria, Canada, Czech Republic, France, Germany, Italy, Poland, Russian Federation, Sweden, UK, USA). The study was done in accordance with the principles delineated in Declaration of Helsinki as revised in Brazil in 2013 [16]. All centers received approval from an independent ethics committee or institutional review board (Supplementary Table S1), and all enrolled patients provided written informed consent before starting the study-related procedures.
Following a screening period of up to 10 weeks, interactive response technology was used to randomly assign 341 eligible patients in a 1:1:1 ratio to one of the three treatment groups:
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(1)
Secukinumab 150 mg load at weeks 0, 1, 2 and 3 followed by dosing every 4 weeks starting at week 4;
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(2)
Secukinumab 150 mg no-load received secukinumab treatment at baseline and placebo at weeks 1, 2 and 3 followed by secukinumab dosing every 4 weeks from week 4;
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(3)
Placebo patients followed the same regime (placebo at weeks 0, 1, 2, 3, 4, 8, 12) and received secukinumab 150 mg s.c. without loading regimen from either week 16 (for placebo non-responders) or week 24 (for placebo responders), with patients being classified as responders when they had ≥ 20% improvement from baseline in tender and swollen joint counts (Supplementary Figure S1).
Randomization was stratified by anti-TNF status [anti-TNF-naïve and anti-TNF-inadequate response or intolerance to these agents (IR)] as pre-specified with no less than 65% of randomized patients planned to be anti-TNF naïve.
Following a protocol amendment patients were allowed to have their 150 mg dose escalated to the 300 mg dose based on physician’s judgment, starting at week 36. Post escalation, a dose of secukinumab 300 mg was administered as two single s.c. injections of secukinumab 150 mg; patients were not allowed to switch to lower doses once the dose had been escalated.
Patients
The key inclusion criteria were patients of either sex aged ≥ 18 years who met the ClASsification criteria for Psoriatic ARthritis (CASPAR) and had active disease (defined as ≥ 3 tender joints out of 78 and ≥ 3 swollen joints out of 76 at baseline), despite previous treatment with NSAIDs plus/minus conventional/biologic DMARDs were included. Patients who had previously used up to three anti-TNF agents at an approved dose for at least 3 months could enroll if they had an inadequate response or had stopped treatment because of safety or tolerability reasons (anti-TNF-IR) after an appropriate washout period prior to randomization. Patients on prescribed NSAIDs were required to be on a stable dose for at least 2 weeks before randomization and were required to remain on a stable dose up to week 24. Patients could continue to receive the following medications at a stable dose for at least 2 weeks: prednisone or equivalent (≤ 10 mg/day); methotrexate (≤ 25 mg/week).
Key exclusion criteria included patients with previous exposure to secukinumab or any other biologic drug directly targeting the IL-17 or IL-17 receptor. Also excluded were patients with active infection in the 2 weeks before randomization or those with a history of ongoing, chronic or recurrent infections, or evidence of tuberculosis infection or with active inflammatory diseases other than psoriatic arthritis. Patients with a history of malignant disease within the past 5 years (excluding basal cell carcinoma or actinic keratoses, in situ cervical cancer or non-invasive malignant colon polyps) and those having chest X-ray/magnetic resonance imaging (MRI) with evidence of an ongoing infectious or malignant process, obtained within 3 months prior to screening, were also excluded.
Outcomes
The primary efficacy end point was the proportion of patients achieving ACR20 response at week 16 with secukinumab versus placebo. Secondary end points were assessed as part of a predefined hierarchical hypothesis-testing strategy at week 16 with secukinumab versus placebo and included change from baseline in the 28-joint Disease Activity Score including levels of C-reactive protein (DAS28-CRP), Psoriasis Area Severity Index 75 (PASI 75) response in patients with psoriasis affecting ≥ 3% body surface area, change from baseline in the physical component summary score of the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36 PCS score), ACR50 response and ACR20 response at week 4. Overall safety and tolerability was also assessed.
Pre-specified exploratory end points included assessment of ACR70 responses, PASI 90 responses, change from baseline in Health Assessment Questionnaire-Disability Index (HAQ-DI) score and Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F), minimal disease activity (MDA) responses and resolution of dactylitis and enthesitis at week 16, 52 and 104, subgroup analyses of ACR20/50 responses by previous anti-TNF therapy status and comparison between the secukinumab regimens up to week 16 for all the primary and secondary end points. In addition, the primary and secondary end points were also assessed at week 52 and 104.
ACR and PASI responses were also evaluated pre- and post-escalation (12–16, 20–24 weeks after the escalation happened): patients were grouped into four ranges based on their response: no (< 20); low (≥ 20 to < 50); moderate (≥ 50 to < 70); high (≥ 70) ACR responses. Similarly, ranges for PASI responses were: no (< 50); low (≥ 50 and < 75); moderate (≥ 75 and < 90); high (≥ 90).
The overall safety and tolerability were assessed by monitoring frequency of adverse events (AEs), laboratory abnormalities, electrocardiogram findings and vital signs. Biochemical investigations were classified according to the Common Terminology Criteria for Adverse Events (version 4).
Statistical Analysis
A sequential hierarchical testing method was used to maintain the family-wise type 1 error rate at 5% across the primary and ranked secondary end points. If the primary efficacy analysis was significant, secondary analyses were completed in the following sequence: DAS-28-CRP, PASI 75, SF36-PCS and ACR50 at week 16.
The primary end point, ACR20 at week 16, was analyzed by logistic regression with treatment and anti-TNF status as a factor and weight as a covariate. Missing values were imputed as non-responders. Efficacy data for secukinumab 150 mg load and no-load regimens are reported for originally randomized patients after application of non-responder imputation to missing binary variables and a mixed-effect model repeated measures for continuous variables until week 52, and as observed through week 104.
After protocol amendment, starting as early as week 36, the secukinumab 150 mg load and no-load groups included all the patients who had their dose escalated from 150 to 300 mg. Post-escalation data are presented as Sankey plots.
Safety analysis included all patients who received ≥ 1 dose of secukinumab, and data are presented as exposure-adjusted incidence rates (EAIR) per 100 patient-years over the entire treatment period. Safety results are presented for any secukinumab 150 mg and 300 mg group. Any secukinumab 150 mg included all patients who were originally randomized to secukinumab 150 mg and placebo-switchers at week 16 or 24. Any secukinumab 300 mg group included patients who had their dose escalated from secukinumab 150 to 300 mg during the study. For those patients who had their dose escalated, safety data were summarized separately based on the actual treatment received before and after dose escalation.