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

Trial statusNot yet recruiting
Trial phasePhase 2
Trial typeInterventional
Biological sexAll
Age12+
Sponsorargenx

About this trial

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 criteria

This trial does not accept healthy volunteers

Qualifiers

Is at least 12 years of age.

Meeting at least the criteria for possible AIE according to the Graus criteria.

Disqualifiers

Known anti-myelin oligodendrocyte glycoprotein (anti-MOG) antibody positivity.

Any medical condition that would interfere with an accurate assessment of clinical symptoms of AIE.

Recent major surgery (within 3 months of screening) or intention to have major surgery during the study, except for surgeries for AIE-related teratomas and thymomas.

History (within 12 months before screening) of current alcohol, drug (including recreational or prescribed cannabinoids), or medication abuse.

Trial design

Design model

Parallel

Treatments tested in this trial

  • Efgartigimod PH20 (ARGX-113) SC

    Biological/Vaccine

    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 intervention

    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

Treatment groups

170 Participants
are divided into 4 treatment groups
Group A: Part A (Open-Label Lead-in Period): Efgartigimod PH20 SCExperimental treatment 1 intervention
Group B: Part B (Double-blinded treatment period): Efgartigimod PH20 SCExperimental treatment 1 intervention
Group C: Part B (Maintenance double-blinded treatment period): Placebo PH20 SCPlacebo comparator 1 intervention
Group D: Part C (Open-Label Extension Period): Efgartigimod PH20 SCExperimental treatment 1 intervention

Trial outcomes

Primary outcomes

1

Change in CASE score in the NMDAR population

CASE= Clinical Assessment Scale in Autoimmune Encephalitis; NMDAR=N-methyl-D-aspartate receptor; Neuropsychological Status. The CASE (Clinical Assessment Scale in AIE) includes an assessment of 9 items: seizure, memory dysfunction, psychiatric symptoms, consciousness, language problems, dyskinesia/dystonia, gait instability and ataxia, brainstem dysfunction, weakness. This overall CASE total score ranges from 0 to 27, with a higher score indicating a greater degree of disability.

Time frame
up to week 24

Secondary outcomes

1

Change in mRS

The mRS (modified Rankin Scale) is commonly used to measure the degree of disability or dependence in the daily activities of people with neurological disabilities. Scores range from 0 (no symptoms) to 6(dead).

Time frame
up to week 8
2

Change in CASE score

The CASE (Clinical Assessment Scale in AIE) includes an assessment of 9 items: seizure, memory dysfunction, psychiatric symptoms, consciousness, language problems, dyskinesia/dystonia, gait instability and ataxia, brainstem dysfunction, weakness. This overall CASE total score ranges from 0 to 27, with a higher score indicating a greater degree of disability.

Time frame
up to week 8
3

Change in MoCA total score

MoCA= Montreal Cognitive Assessment

Time frame
up to week 8
4

Change in NPI-C total score

The NPI-C (Neuropsychiatric Inventory--Clinician) total score will be used as a global measure of neuropsychiatric symptoms.Total score is calculated by summing the scores of all the individual domains.Each domain score is determined by summing the item scores within that domain. The NPI-C uses a clinician rating method, where ratings for frequency, severity, and caregiver distress are provided for each item.These item scores are then summed to create a total domain score.

Time frame
up to week 8

Other outcomes

Sponsors and contacts

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