RecruitingPhase 2NCT07583641

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

A Global, Multicenter, Randomized, Double-Blinded, Placebo-Controlled, Phase 2 Study to Evaluate the Efficacy, Safety, and Tolerability of Efgartigimod PH20 SC in Adult and Adolescent Participants With Autoimmune Encephalitis

Sponsor

argenx

Enrollment

170 participants

Start Date

Aug 15, 2026

Study Type

INTERVENTIONAL

Conditions

Autoimmune Encephalitis (AE)

Summary

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

Eligibility

Min Age: 12 Years

Plain Language Summary

Simplified for easier understanding

This clinical trial is studying a biological treatment called Efgartigimod PH20 (ARGX-113) SC and Placebo PH20 SC for people with autoimmune encephalitis (ae). The study is currently recruiting participants at 2 locations.

This summary was AI-generated to explain the trial in plain language. It is not medical advice. Always discuss eligibility with your doctor before enrolling in a clinical trial.

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Interventions

BIOLOGICALEfgartigimod PH20 (ARGX-113) SC

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.

OTHERPlacebo PH20 SC

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