A Study to Examine the Efficacy and Safety of Pozelimab and Cemdisiran Combination Therapy in Adult Patients With Symptomatic Generalized Myasthenia Gravis

About the study

The primary objective is: To evaluate the effect of pozelimab + cemdisiran on daily functioning that is impacted by signs and symptoms in patients with symptomatic generalized myasthenia gravis (gMG) The secondary objectives of the study are: To evaluate the effect of pozelimab + cemdisiran (ie, combination) and cemdisiran monotherapy on: Clinician-assessed signs of myasthenia gravis (MG) and muscle strength Daily functioning that is impacted by signs and symptoms in patients with symptomatic gMG (cemdisiran monotherapy only). Proportion of patients with improvements in daily function that is impacted by signs and symptoms of MG Proportion of patients that have improvements in clinician-assessed signs of MG and muscle strength Health related quality of life Proportion of patients with minimal MG symptoms Patient- and clinician-reported signs and symptoms of MG To evaluate the safety and tolerability of pozelimab + cemdisiran and cemdisiran monotherapy To assess the concentration of total pozelimab in serum To assess the concentrations of cemdisiran and its metabolites in plasma To assess the immunogenicity of pozelimab To assess the concentration of total C5 in plasma To assess the immunogenicity of cemdisiran To study the effect of pozelimab + cemdisiran and cemdisiran monotherapy on complement activation

Who can take part

You may be eligible to participate in the study if you meet the following criteria:

INCLUSION CRITERIA

Key Inclusion Criteria:

Male or female patients ≥18 years of age at screening (or ≥ legal age of adulthood based on local regulations, whichever is older)
Patient with documented diagnosis of myasthenia gravis (MG) based on medical history and supported by previous evaluations as described in the protocol
Documented prior history of positive serologic test or a positive result during screening of anti-acetylcholine receptor (AChR) antibodies or anti-LRP4 antibodies.
Myasthenia Gravis Foundation of America (MGFA) Clinical Classification Class II to IVa at screening
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
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).

EXCLUSION CRITERIA

Key Exclusion Criteria:

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
History of thymectomy within 12 months prior to screening or planned during the study
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
Myasthenic crisis or Myasthenia Gravis Foundation of America (MGFA) Class V within 1 month of screening
No documented meningococcal vaccination within 5 years prior to screening visit unless vaccination will be administered during the screening period and prior to initiation of study treatment
Known contraindication to meningococcal vaccines (group ACWY conjugate and group B vaccines) as described in the protocol
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
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
History of HIV infection or a positive test at screening per local requirements

NOTE: Other protocol-defined Inclusion/ Exclusion Criteria apply