Adding empasiprubart to efgartigimod for AChR-antibody positive generalized myasthenia gravis

An ISA to Master Protocol ARGX-999-2-MG-2000 for an Exploratory, Phase 2a, Proof-of-Concept Study to Evaluate the Safety, Tolerability, and Efficacy of Empasiprubart IV as Add-On Therapy to Efgartigimod IV in Participants With AChR-Ab Seropositive Generalized Myasthenia Gravis With a Partial Clinical Response to Efgartigimod

Phase 2 Interventional argenx · NCT07284420

This trial will test whether adding empasiprubart to efgartigimod infusions helps people with AChR-antibody positive generalized myasthenia gravis who have only had a partial response to efgartigimod.

Quick facts

PhasePhase 2
Study typeInterventional
Enrollment70 (estimated)
Ages18 Years and up
SexAll
Sponsorargenx Industry-sponsored
Drugs / interventionseculizumab, ravulizumab
Locations9 sites (Carlsbad, California and 8 other locations)
Trial IDNCT07284420 on ClinicalTrials.gov

What this trial studies

This Phase 2 add-on study enrolls AChR-Ab seropositive participants with generalized myasthenia gravis who complete a run-in period of efgartigimod IV (part A). Eligible participants then enter an add-on period (part B) receiving both efgartigimod IV and empasiprubart IV, while those not eligible proceed to a safety follow-up (part C) receiving efgartigimod alone. The trial is conducted under the ADAPT Forward platform protocol and includes screening, treatment, and follow-up visits over roughly 54 weeks per participant. All participants must meet vaccination requirements for encapsulated bacteria or be willing to be vaccinated before dosing.

Who should consider this trial

Good fit: Adults with AChR-Ab seropositive generalized myasthenia gravis (MGFA class II–IV) who have shown a partial clinical response to efgartigimod and who are vaccinated or willing to be vaccinated against Neisseria meningitidis and Streptococcus pneumoniae.

Not a fit: People with systemic lupus erythematosus, known complement deficiencies, recent use of complement inhibitors (within protocol-specified windows), or those proven refractory to efgartigimod are unlikely to receive benefit from this add-on approach.

Why it matters

Potential benefit: If successful, adding empasiprubart could improve symptom control for people who only partially respond to efgartigimod and potentially reduce the need for other immunosuppressive treatments.

How similar studies have performed: Efgartigimod has demonstrated clinical benefit in gMG in prior studies, while empasiprubart as an add-on therapy represents a newer approach with limited published data to date.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Is seropositive for anti-acetylcholine receptor antibodies (AChR-Ab)
* Has confirmed diagnosis of gMG and is Myasthenia Gravis Foundation of America (MGFA) Class II, III, IVa, or IVb
* Has documented immunization against encapsulated bacterial pathogens (Neisseria meningitidis and Streptococcus pneumoniae) within 5 years of ISA screening or is willing to receive immunization at least 14 days before the first study drug administration

Exclusion Criteria:

* Clinical diagnosis of systemic lupus erythematosus (SLE)
* Any known complement deficiency
* Current administration of a complement inhibitor or received zilucoplan or eculizumab \<2 months or ravulizumab \<6 months before the first study drug administration
* Patients proven to be refractory to efgartigimod (ie, not achieving a clinically meaningful improvement in total Myasthenia Gravis Activities of Daily Living (MG-ADL) score defined as an improvement of ≥2 points)

Where this trial is running

Carlsbad, California and 8 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions AChR-Ab Seropositive Generalized Myasthenia GravisMyasthenia GravisMGgMGGeneralized Myasthenia Gravis
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.