A Phase 3 interventional study of Pozelimab + Cemdisiran and Cemdisiran in Generalized Myasthenia Gravis, sponsored by Regeneron Pharmaceuticals. Active, not recruiting at 116 sites in 19 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-07-08.
Sponsored by Regeneron Pharmaceuticals · Phase 3, Interventional, and Treatment
This study is researching the experimental drugs called pozelimab and cemdisiran, and cemdisiran monotherapy. The study is focused on patients with generalized Myasthenia Gravis (gMG). Myasthenia gravis is a disease that causes weakness and fatigue in muscles in the body because the nerves and muscles are not communicating properly.
The aim of the study is to see how effective pozelimab and cemdisiran are when used in combination and when pozelimab and cemdisiran are used alone for patients with gMG.
The study is looking at several other research questions, including:
DBTP- Double Blind Treatment Period (24 weeks) ETP - Extension Treatment Period (28 weeks) OLTP- Open Label Treatment Period (68 weeks) FUP-Off treatment Follow Up Period (52 weeks)
324 studies on the registry are indexed under Myasthenia Gravis; 146 are open to participants now.
This study's enrollment of 288 is above the median of 44 across 212 interventional studies indexed under Myasthenia Gravis.
Browse Myasthenia Gravis studies →Regeneron Pharmaceuticals is the lead sponsor of 400 studies on the registry; 91 are open to participants now.
Of its 120 completed or terminated interventional studies of FDA-regulated products, 77 (64%) have results posted.
Counted across the registry records on this site, refreshed daily.
Key Inclusion Criteria:
Key Exclusion Criteria:
NOTE: Other protocol-defined Inclusion/ Exclusion Criteria apply
Placebo in DBTP; Re-randomized to Combination or Cemdisiran in ETP and OLTP
Drug: Pozelimab + Cemdisiran · Drug: Cemdisiran · Other: Placebo
Combination regimen throughout the study. For participants who have not reached week 108 will receive cemdisiran monotherapy in the OLTP.
Drug: Pozelimab + Cemdisiran · Drug: Cemdisiran
Cemdisiran throughout the study
Drug: Cemdisiran
Pozelimab monotherapy in DBTP followed by combination in ETP and OLTP. For participants who have not reached week 108 will receive cemdisiran monotherapy in the OLTP.
Drug: Pozelimab + Cemdisiran · Drug: Cemdisiran · Drug: Pozelimab
Subcutaneous administration as described in the protocol
SC administration as described in the protocol
Also known as: ALN-CC5
SC administration as described in the protocol
SC administration as described in the protocol
Also known as: REGN3918
Change in Myasthenia Gravis-Activities of Daily Living (MG-ADL) total score
The total MG-ADL score ranges from 0 to 24 points, with higher scores indicating greater functional impairment and disability
Time frame: From baseline to week 24
Change from baseline in Quantitative Myasthenia Gravis (QMG) score
QMG total scores range from 0 to 39, with higher scores representing greater impairment
Time frame: Week 24
Achievement of a ≥3-point reduction (improvement) in MG-ADL total score
Time frame: From baseline to week 24
Achievement of a ≥5-point reduction (improvement) in QMG total score
Time frame: From baseline to week 24
Achievement of a consistent response on the MG-ADL
A participant with a ≥2-point reduction (improvement) in MG-ADL total score on 2 or more consecutive assessments spanning 4 or more weeks during the DBTP
Time frame: From baseline to week 24
Achievement of Minimal Symptom Expression (MSE)
Score of 0 to 1 on the MG-ADL
Time frame: Week 24
Change from baseline in the Myasthenia Gravis Composite (MGC) total score
MGC score ranges from 0 to 50, with higher score indicating higher impairment
Time frame: Week 24
Change from baseline in Myasthenia Gravis Quality of Life (MG-QOL15r) total score
Total score ranges from 0 to 30 points; a higher score represents greater impairment
Time frame: Week 24
Achievement of a ≥2-, 4-, 5-, 6-, 7-, 8-, 9-, or 10-point reduction on MG-ADL total score
Time frame: From baseline to week 24
Achievement of a ≥3-, 4-, 6-, 7-, 8-, 9-, or 10-point reduction on QMG
Time frame: From baseline to week 24
Incidence and severity of Treatment-Emergent Adverse Events (TEAEs) in participants treated with pozelimab + cemdisiran, cemdisiran monotherapy or placebo
Time frame: Through week 24
Incidence and severity of Serious Adverse Events (SAEs) in participants treated with pozelimab + cemdisiran, cemdisiran monotherapy or placebo
Time frame: Through week 24
Incidence and severity of Adverse Events of Special Interest (AESIs) in participants treated with pozelimab + cemdisiran, cemdisiran monotherapy or placebo
Time frame: Through week 24
Concentrations of total pozelimab in serum
Time frame: Through study duration, approximate 172 weeks
Concentrations of total Complement component 5 (C5) in plasma
Time frame: Through study duration, approximate 172 weeks
Concentrations of cemdisiran and its metabolites in plasma
Time frame: Through study duration, approximate 172 weeks
Incidence of treatment-emergent Anti-Drug Antibodies (ADAs) to pozelimab over time
Time frame: Through study duration, approximately 172 weeks
Incidence of treatment-emergent ADAs to cemdisiran over time
Time frame: Through study duration, approximate 172 weeks
Change in total complement hemolysis activity assay (CH50) over time
Time frame: Through study duration, approximately 172 weeks
Percent change in CH50 over time
Time frame: Through study duration, approximately 172 weeks
Showing the first 100 of 116 sites across 19 countries.
Plan to share: Yes — All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing
Supporting information: Study protocol, Sap, Icf, Csr, Analytic code
This study is active, not recruiting, as verified in Jun 2026. You cannot join it, but the record below documents what was studied.
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Regeneron Pharmaceuticals