A Study to Learn About How Well the Medicine Efgartigimod Works to Treat Autoimmune Encephalitis In Children 12 Years or Older and Adults

Sponsor
argenx
Study ID
NCT07583641
Phase
PHASE2
Status
Not Yet Recruiting

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Conditions

  • Autoimmune Encephalitis (AE)

Eligibility Criteria

Sex
ALL
Age
12 Years - N/A
Healthy Volunteers
Not accepted

Interventions

  • Efgartigimod PH20 (ARGX-113) SC — BIOLOGICAL
    subcutaneous administrations of efgartigimod PH20 SC given by prefilled syringe (PFS). For participants aged 12 to \<18 years with body weight ≤50 kg, the study drug will be administered by vial and syringe.
  • Placebo PH20 SC — OTHER
    subcutaneous administrations of placebo PH20 SC given by prefilled syringe (PFS). For participants aged 12 to \<18 years with body weight ≤50 kg, the study drug will be administered by vial and syringe

Study Details

The POLARIS study is designed to evaluate how well efgartigimod PH20 SC may work (called "efficacy") and how safe it is for people diagnosed with Autoimmune Encephalitis (AIE). The study consists of 4 parts: in part A participants will receive efgartigimod SC; in part B, participants will be randomized to receive either efgartigimod SC or placebo; in part C, participants who completed part B will receive efgartigimod SC; in part D, participants who completed part C will be observed after their last dose of efgartigimod SC. If AIE symptoms return, efgartigimod SC treatment may be restarted during this time. The maximum overall study duration for participants is up to 3 years. More information can be found in clinicaltrials.argenx.com/polaris

Key Dates

Start date
Jul 13, 2026
Status verified
May 2026
Primary completion
Dec 4, 2030
Completion
Jul 26, 2031

Study Design

Enrollment
170 participants (estimated)
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT

Arms

  • Experimental: Part A (Open-Label Lead-in Period): Efgartigimod PH20 SC
    All participants will receive efgartigimod PH20 SC open label for 8 weeks
  • Experimental: Part B (Double-blinded treatment period): Efgartigimod PH20 SC
    Participants will receive efgartigimod PH20 SC for 24 weeks
  • Placebo Comparator: Part B (Maintenance double-blinded treatment period): Placebo PH20 SC
    Participants will receive placebo for 24 weeks
  • Experimental: Part C (Open-Label Extension Period): Efgartigimod PH20 SC
    Participants who complete Part B will receive efgartigimod PH20 SC for 24 weeks

Primary Outcome Measure

Change in CASE score in the NMDAR population [ Time Frame: up to week 24 ]

Central Contacts