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Testing the safety and effectiveness of pozelimab and cemdisiran for treating generalized myasthenia gravis

Efficacy and Safety of Pozelimab and Cemdisiran Combination Therapy and Cemdisiran Monotherapy in Patients With Symptomatic Generalized Myasthenia Gravis

Phase 3 Interventional Regeneron Pharmaceuticals · NCT05070858

This study is testing two new drugs, pozelimab and cemdisiran, to see if they can safely help adults with generalized myasthenia gravis feel better.

Quick facts

PhasePhase 3
Study typeInterventional
Enrollment335 (estimated)
Ages18 Years and up
SexAll
SponsorRegeneron Pharmaceuticals Industry-sponsored
Drugs / interventionspozelimab
Locations136 sites (Scottsdale, Arizona and 135 other locations)
Trial IDNCT05070858 on ClinicalTrials.gov

What this trial studies

This study investigates the safety and efficacy of two experimental drugs, pozelimab and cemdisiran, both in combination and alone, for adult patients with generalized myasthenia gravis (gMG). The trial includes a double-blind treatment period lasting 24 weeks, followed by an extension treatment period of 28 weeks and an open-label treatment period of 68 weeks. Researchers will assess side effects, drug interactions, and the presence of antibodies that may affect drug effectiveness. The study aims to provide insights into how these drugs work in the body and their potential benefits for patients with gMG.

Who should consider this trial

Good fit: Ideal candidates include adults aged 18 and older with a documented diagnosis of generalized myasthenia gravis and specific antibody profiles.

Not a fit: Patients with mild myasthenia gravis or those not currently receiving immunosuppressive therapy may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could offer new treatment options that improve muscle strength and reduce fatigue for patients with generalized myasthenia gravis.

How similar studies have performed: Previous studies have shown promise with similar approaches in treating myasthenia gravis, but this specific combination therapy is novel.

Eligibility criteria

Show full inclusion / exclusion criteria 
Key Inclusion Criteria:

1. Male or female patients ≥18 years of age at screening (or ≥ legal age of adulthood based on local regulations, whichever is older)
2. Patient with documented diagnosis of myasthenia gravis (MG) based on medical history and supported by previous evaluations as described in the protocol
3. Documented prior history of positive serologic test or a positive result during screening of anti-acetylcholine receptor (AChR) antibodies or anti-LRP4 antibodies.
4. Myasthenia Gravis Foundation of America (MGFA) Clinical Classification Class II to IVa at screening
5. Myasthenia Gravis-Activities of Daily Living (MG-ADL) score ≥6 at screening. Ocular items should not contribute more than 50% of MG-ADL total score as described in the protocol
6. Currently receiving an acetylcholinesterase inhibitor or documented reason for not using acetylcholinesterase inhibitor therapy per investigator
7. Currently receiving an immunosuppressive therapy (IST) for MG, or documented reason why the patient is not taking an IST per investigator
8. If currently receiving an IST, not anticipated to have IST dosage changed before randomization or during double-blind treatment period (DBTP).
9. Willing and able to comply with clinic visits and study-related procedures, including completion of the primary series of the meningococcal vaccinations required per protocol

Key Exclusion Criteria:

1. Patients with antibody profile that is only positive for muscle specific tyrosine kinase (MuSK) (MuSK positivity is based on a documented prior history of positive serologic test for antibodies to MuSK or a positive result during screening
2. History of thymectomy within 12 months prior to screening or planned during the study
3. History of malignant thymoma (patients with stage 1 may be enrolled), or history of cancer within the past 5 years, except for adequately treated basal cell skin cancer, squamous cell skin cancer, or in situ cervical cancer
4. Myasthenic crisis or Myasthenia Gravis Foundation of America (MGFA) Class V within 1 month of screening
5. Not meeting meningococcal vaccination requirements and, at a minimum, documentation of quadrivalent meningococcal vaccination within 5 years prior to randomization and serotype B vaccine (when available) within 3 years prior to randomization as described in the protocol
6. Known contraindication to meningococcal vaccines (group ACWY conjugate and group B vaccines) as described in the protocol
7. Patients who require antibiotics for meningococcal prophylaxis and have a contraindication, warning, or precaution precluding the use of penicillin class and penicillin-alternative antibiotics planned to be used for prophylaxis, or a history of intolerance leading to the discontinuation of these antibiotics
8. Positive hepatitis B surface antigen or hepatitis C virus ribonucleic acid (RNA) during screening. NOTE: Cases with unclear interpretation should be discussed with the medical monitor
9. History of HIV infection or a positive test at screening per local requirements

NOTE: Other protocol-defined Inclusion/ Exclusion Criteria apply

Where this trial is running

Scottsdale, Arizona and 135 other locations

+86 more sites — see ClinicalTrials.gov for the full list.

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.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Generalized 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.