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

Study acronym: Polaris

StatusNot Yet Recruiting

PhasePhase 2

Sponsorargenx

Started2027-04-01

View on ClinicalTrials.gov ↗

Trial flagged as At Risk

Primary completion moved at least 17 months later Jan 20, 2029 → Jul 2030

See other at-risk trials from Argenx

Amendment history

2026-09-23

Trial status changed: Recruiting → Not Yet Recruiting

Primary completion pushed: 2029-01-20 → 2030-07

Completion pushed: 2029-05-12 → 2030-07-30

2026-08-21

Study Status, Contacts/Locations v3

Recruitment opened

Start date2026-07-13→2026-08-15

Study sites1→2

2026-08-06

Study Status, Contacts/Locations v2

Study sites0→1

2026-07-17

Study Status v1

Primary completion moved earlier: 2030-12-04 → 2029-01-20

Completion moved earlier: 2031-07-26 → 2029-05-12

2026-05-07

Original filing

Argenx

56 trials monitored

See 2 trials at risk

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

Trial Details

NCT Number	NCT07583641
Lead Sponsor	argenx
Conditions	Autoimmune Encephalitis (AE)
Enrollment	170 participants
Start Date	2027-04-01
Primary Completion	2030-07 (estimated)
Study Completion	2030-07-30 (estimated)
Updated on ClinicalTrials.gov	2026-09-22