A Randomized, Parallel-group, Double-blind, Placebo-controlled, Multicenter Phase III Trial to Investigate the Efficacy and Safety of Secukinumab 300 mg and 150 mg Administered Subcutaneously Versus Placebo, in Combination With a Glucocorticoid Taper Regimen, in Patients With Giant Cell Arteritis (GCA) (GCAptAIN)


This is a phase III study of the efficacy and safety of secukinumab versus placebo, in combination with glucocorticoid taper regimen, in patients with giant cell arteritis (GCA).

Study Arms

  • Experimental: Secukinumab 300 mg
  • Placebo Comparator: Placebo
  • Experimental: Secukinumab 150 mg 


  1. Signed informed consent must be obtained prior to participation in the study.
  2. Patient must be able to understand and communicate with the investigator and comply with the requirements of the study.
  3. Male or non-pregnant, non-lactating female patients at least 50 years of age.
  4. Diagnosis of GCA based on meeting all of the following criteria:
    • Age at onset of disease ≥ 50 years.
    • Unequivocal cranial symptoms of GCA (e.g., new-onset localized headache, scalp or temporal artery tenderness, permanent or temporary ischemia-related vision loss, or otherwise unexplained mouth or jaw pain upon mastication), and/or unequivocal symptoms of polymyalgia rheumatica (PMR) (defined as shoulder and/or hip girdle pain associated with inflammatory morning stiffness) and/or symptoms of limb ischemia (claudication).
    • TAB revealing features of GCA and/or cross-sectional imaging study such as ultrasound (e.g., cranial or axillary), MRI/MRA, CTA, or PET-CT with evidence of vasculitis.
  5. Active disease as defined by meeting both of the following within 6 weeks of BSL (see Section 8.1 for details)
    • Presence of signs or symptoms attributed to active GCA and not related to prior damage (e.g., visual loss that occurred prior to 6 weeks before BSL without new findings occurring within 6 weeks of BSL)
    • Elevated ESR ≥ 30 mm/hr or CRP ≥ 10 mg/L attributed to active GCA or active GCA on TAB or on imaging study.
  6. Patients to meet definition of new-onset GCA or relapsing GCA:
    • Definition of new-onset GCA*: GCA that is diagnosed within 6 weeks of BSL visit
    • Definition relapsing GCA:
    • GCA diagnosed > 6 weeks before BSL visit and
    • Following institution of an appropriate treatment course for GCA, participant has experienced recurrence of active symptoms or signs of disease after resolution.
      • The 6-week timeframe is to be calculated from the date of suspected GCA diagnosis. Suspected diagnosis is defined as date when GC therapy was initiated.
  7. Patients' current GCA episode should be treatable with a dose of prednisone (or equivalent) designed to adequately achieve disease control in accordance with international guidelines. If this is not possible due to concerns regarding GC toxicity, the patient should not be enrolled. It must be medically appropriate for the patient to receive prednisone (or equivalent) 20 mg-60 mg daily (or equivalent) at BSL.
  8. Patients taking MTX (≤ 25 mg/week) are allowed to continue their medication provided they have taken it for at least 2 months and are on a stable dose for at least 4 weeks prior to randomization and if they are on stable folic acid treatment before randomization.