Study to Demonstrate the Efficacy (Including Inhibition of Structural Damage), Safety and Tolerability up to 2 Years of Secukinumab in Active Psoriatic Arthritis

This multicenter study uses a randomized, double-blind, placebo-controlled, parallel-group design. A screening period (SCR) running up to 10 weeks before randomization will be used to assess subject eligibility followed by 104 weeks of treatment.

At BSL approximately 990 subjects whose eligibility is confirmed will be randomized to one of four treatment groups in 2:2:2:3 ratio:

• Group 1 - secukinumab 150 mg s.c. without loading regimen
• Group 2 - secukinumab 150 mg s.c. with loading dose regimen
• Group 3 - secukinumab 300 mg s.c. with loading dose regimen
• Group 4 - Placebo s.c. NOTE: Group 4 is split into 2 treatment arms, detailed description below. At randomization, subjects will be stratified on the basis of previous anti-TNF therapy as TNFα inhibitor naïve (TNF-naïve) or TNFα inhibitor inadequate responders (TNF-IR).

At each study treatment visit, one (for secukinumab 150 mg) or two (for secukinumab 300 mg) s.c. injections in the form of PFS will be administered, since secukinumab is available in 1.0 mL (150 mg) PFSs. Placebo to secukinumab is also available in 1.0 mL to match the active drug.

At Week 16, subjects who have been randomized to secukinumab groups at BSL (Groups 1-3) will be classified as either responders (≥20% improvement from BSL in both tender joint count (TJC) and swollen joint counts (SJC)) or non-responders (<20% improvement from BSL TJC or SJC), however they will continue on the same treatment irrespective of their response status.

At Week 16, subjects who have been randomized to placebo at BSL (Group 4) will be classified as either responders (≥20% improvement from BSL in both TJC and SJC) or non-responders (<20% improvement from BSL TJC or SJC):

• Subjects who are non-responders will receive either secukinumab 150 mg or 300 mg s.c. every 4 weeks starting at Week 16 (as dictated by treatment sequence assigned to these subjects at BSL).
• Subjects who are responders will continue to receive placebo every 4 weeks. Starting Week 24, these subjects will receive either secukinumab 150 mg s.c. or 300 mg s.c. every 4 weeks starting at Week 24 (as dictated by treatment sequence assigned to these subjects at BSL).

At Week 24, the assessments to address the primary objective will be performed. As described above, subjects who are still receiving placebo s.c. injection will receive either secukinumab 150 mg s.c. or 300 mg s.c. every 4 weeks starting at Week 24 (as dictated by treatment sequence assigned to these subjects at BSL).

At week 52, based on Investigator's decision, the subjects on a 150 mg dose whose signs and symptoms do not show satisfactory response have the possibility to be allocated to secukinumab 300 mg s.c.

After the Week 52 database lock and analyses have been completed, site personnel and subjects will be unblinded to the original randomized treatment (sequence) assignment at randomization. In addition, treatment will be given open-label in order to eliminate the placebo injection. The subject will continue to receive the same active dose of secukinumab as open-label treatment administered until Week 100.

Inclusion criteria

Diagnosis of PsA classified by CASPAR criteria and with symptoms for at least 6 months with moderate to severe PsA who must have at BSL ≥3 tender joints out of 78 and ≥3 swollen joints out of 76 (dactylitis of a digit counts as one joint each).

• Rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP) antibodies negative at screening.
• Diagnosis of active plaque psoriasis or nail changes consistent with psoriasis or a documented history of plaque psoriasis.
• Subjects with PsA should have taken NSAIDs for at least 4 weeks prior to randomization with inadequate control of symptoms or at least one dose if stopped due to intolerance to NSAIDs.-Subjects who are regularly taking NSAIDs as part of their PsA therapy are required to be on a stable dose for at least 2 weeks before study randomization and should remain on a stable dose up to Week 24.
• Subjects taking corticosteroids must be on a stable dose of ≤10 mg/day prednisone or equivalent for at least 2 weeks before randomization and should remain on a stable dose up to Week 24.
• Subjects taking MTX (≤ 25 mg/week) are allowed to continue their medication if the dose is stable for at least 4 weeks before randomization and should remain on a stable dose up to Week 52.
• Subjects on MTX must be on folic acid supplementation at randomization.
• Subjects who are on a DMARD other than MTX must discontinue the DMARD 4 weeks prior to randomization visit except for leflunomide, which has to be discontinued for 8 weeks prior to randomization unless a cholestyramine wash-out has been performed.
• Subjects who have been on a TNFα inhibitor must have experienced an inadequate response to previous or current treatment with a TNFα inhibitor given at an approved dose for at least 3 months or have stopped treatment due to safety/tolerability problems after at least one administration of a TNFα inhibitor.
• Subjects who have previously been treated with TNFα inhibitors (investigational or approved) will be allowed entry into study after appropriate wash-out period prior to randomization

Exclusion criteria

Chest X-ray or chest MRI with evidence of ongoing infectious or malignant process. - Subjects taking high potency opioid analgesics.

• Previous exposure to secukinumab or other biologic drug directly targeting IL-17 or IL-17 receptor. - Ongoing use of prohibited psoriasis treatments / medications (e.g., topical corticosteroids, UV therapy) at randomization.
• Any intramuscular or intravenous or intra-articular corticosteroid treatment within 4 weeks before randomization.
• Subjects who have ever received biologic immunomodulating agents except for those targeting TNFα (investigational or approved).
• Previous treatment with any cell-depleting therapies including but not limited to anti- CD20, investigational agents
• Other protocol-defined exclusion criteria do apply