Efficacy and Safety of Ixekizumab in Patients with Active Psoriatic Arthritis: 52-week Results from a Phase III Study (SPIRIT-P1)

J Rheumatol. 2018 Mar;45(3):367-377. doi: 10.3899/jrheum.170429. Epub 2017 Dec 15.


Objective: To evaluate the efficacy and safety of ixekizumab (IXE), an interleukin 17A antagonist, in patients with psoriatic arthritis (PsA) after 52 weeks in a phase III study.

Methods: Patients were initially randomly assigned to IXE 80 mg every 2 weeks (IXEQ2W) or every 4 weeks (IXEQ4W) after a 160-mg starting dose, placebo (PBO), or adalimumab (ADA) 40 mg Q2W. At Week 24 (Week 16 for inadequate responders), ADA (8-week washout before starting IXE) and PBO patients were rerandomized to IXEQ2W or IXEQ4W. Six treatment groups were evaluated in the extension period (weeks 24-52): IXEQ2W/IXEQ2W, IXEQ4W/IXEQ4W, ADA/IXEQ2W, ADA/IXEQ4W, PBO/IXEQ2W, and PBO/IXEQ4W. The extension period population (EPP) included patients who received ≥ 1 dose of study medication during the extension period.

Results: There were 381/417 (91.4%) patients who entered the extension period. In the IXEQ4W/IXEQ4W and IXEQ2W/IXEQ2W groups (EPP), respectively, American College of Rheumatology (ACR)20 (69.1% and 68.8%), ACR50 (54.6% and 53.1%), and ACR70 (39.2% and 39.6%) response rates were sustained at Week 52. Patients rerandomized to IXE also demonstrated efficacy measured by ACR response rates at Week 52. A similar pattern was observed for Psoriasis Area and Severity Index outcomes. Radiographic progression in all 6 groups was minimal. The most frequently reported treatment-emergent adverse events (≥ 4%) were nasopharyngitis, injection site reaction, injection site erythema, upper respiratory tract infection, and back pain. No deaths were reported, and serious adverse event frequency was 0-4% with IXE.

Conclusion: During the extension period, IXEQ4W or IXEQ2W treatment demonstrated sustained efficacy in key PsA domains with a safety profile consistent with other studies investigating IXE. Clinical trial number: NCT01695239; EudraCT 2011-002326-49.


Publication types

  • Clinical Trial, Phase III
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adalimumab / administration & dosage
  • Adalimumab / therapeutic use
  • Adult
  • Antibodies, Monoclonal, Humanized / administration & dosage
  • Antibodies, Monoclonal, Humanized / adverse effects*
  • Antibodies, Monoclonal, Humanized / pharmacology
  • Antibodies, Monoclonal, Humanized / therapeutic use*
  • Antirheumatic Agents / administration & dosage
  • Antirheumatic Agents / therapeutic use
  • Arthritis, Psoriatic / drug therapy*
  • Back Pain / chemically induced
  • Dermatologic Agents / administration & dosage
  • Dermatologic Agents / adverse effects*
  • Dermatologic Agents / pharmacology
  • Dermatologic Agents / therapeutic use*
  • Double-Blind Method
  • Female
  • Humans
  • Injection Site Reaction / etiology
  • Interleukin-17 / antagonists & inhibitors
  • Male
  • Middle Aged
  • Nasopharyngitis / chemically induced
  • Quality of Life
  • Respiratory Tract Infections / etiology
  • Severity of Illness Index
  • Treatment Outcome


  • Antibodies, Monoclonal, Humanized
  • Antirheumatic Agents
  • Dermatologic Agents
  • IL17A protein, human
  • Interleukin-17
  • ixekizumab
  • Adalimumab

Associated data

  • ClinicalTrials.gov/NCT01695239