A Study to Evaluate the Efficacy and Safety of Maintenance Ublituximab Following Induction With Efgartigimod Administration in Participants With Myasthenia Gravis (MG)

A Phase 2, Randomized, Double-blind, Multicenter, Placebo-controlled Study to Evaluate the Efficacy and Safety of Maintenance Ublituximab Treatment Following Induction With Efgartigimod Administration in Adults With Myasthenia Gravis

The primary purpose of this study is to evaluate the efficacy of ublituximab in adult participants with MG responding to treatment with efgartigimod.

Study Overview

• Status: Recruiting
• Conditions: Myasthenia Gravis
• Intervention / Treatment: Drug: Ublituximab; Drug: Placebo

• Study Type: Interventional
• Enrollment (Estimated): 120
• Phase: Phase 2

Contacts and Locations

• Study Contact: Name: TG Therapeutics Clinical Support Team; Phone Number: 1-877-575-8489; Email: clinicalsupport@tgtxinc.com

Study Locations

• United States
  • Colorado
    • Colorado Springs, Colorado, United States, 80919
      • Recruiting
      • TG Therapeutics Investigational Trial Site
  • Florida
    • Clearwater, Florida, United States, 33761
      • Recruiting
      • TG Therapeutics Investigational Trial Site

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Documentation of MG diagnosis.
2. Eligible for treatment with efgartigimod per effective local product label, confirmed by serological testing at screening.
3. MG-ADL score at the time of screening more than or equal to (≥) 6 and less than or equal to (≤) 10 with more than (>) 50 percent (%) of this score attributed to non-ocular items, or an MG-ADL score ≥ 11.

Exclusion Criteria:

1. Active chronic (or stable but treated with immune therapy) disease of the immune system other than MG (e.g., rheumatoid arthritis, scleroderma, Sjögren's syndrome, Crohn's disease, ulcerative colitis, etc.) or immunodeficiency syndrome (hereditary immune deficiency, drug-induced immune deficiency, etc.).
2. Lack of efficacy or observed safety concerns from prior neonatal Fc receptor (FcRn) treatment.
3. Prior treatment with B-cell depleting therapy, alemtuzumab, total lymphoid irradiation, bone marrow transplant, T-cell vaccination therapy, or natalizumab at any time prior to screening.
4. Participants with significantly impaired organ function.
5. History of life-threatening injection/infusion related reaction (IRR/ISR), hypersensitivity, or anaphylactic reaction with components of efgartigimod or ublituximab solutions, protocol-allowed rescue medications, or protocol required pre-treatment medications.
6. Unwillingness or inability to comply with study and/or follow-up procedures outlined in the protocol.

Note: Other protocol-specified Inclusion/Exclusion criteria may apply.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Randomized controlled period (RCP); Responder participants from efgartigimod induction period will be randomised 1:1 ratio to receive either ublituximab or ublituximab matching-placebo intravenous (IV) infusion.	Drug: Ublituximab; Administered as an IV infusion.; Other Names: BRIUMVI; Drug: Placebo; Administered as an IV infusion.
Experimental: Open-label period (OLP): Ublituximab; Non-responder participants from efgartigimod induction period will receive ublituximab IV infusion.	Drug: Ublituximab; Administered as an IV infusion.; Other Names: BRIUMVI

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Time to Onset of a Clinical Worsening Event	Up to Week 24

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants with Treatment-Emergent Adverse Events (TEAEs)		Up to Week 72
Maximum Plasma Concentration (Cmax) of Ublituximab		Up to Week 72
Proportion of Participants with Cluster of Differentiation 19 + (CD19+) B-cell Counts		Up to Week 72
Change From Baseline in Myasthenia Gravis-Activities of Daily Living (MG-ADL) Total Score in RCP	The MG-ADL scale focuses on relevant symptoms and functional performance of activities of daily living in participants with MG. The total score varies between 0-24, with higher score indicating more severe disease.	Baseline, Week 24

Collaborators and Investigators

• Sponsor: TG Therapeutics, Inc.

Study record dates

Study Major Dates

• Study Start (Estimated): July 30, 2026
• Primary Completion (Estimated): July 1, 2028
• Study Completion (Estimated): January 1, 2030

Study Registration Dates

• First Submitted: June 10, 2026
• First Submitted That Met QC Criteria: June 22, 2026
• First Posted (Actual): June 29, 2026

Study Record Updates

• Last Update Posted (Actual): June 29, 2026
• Last Update Submitted That Met QC Criteria: June 22, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Nervous System Diseases; Neoplasms by Site; Neoplasms; Neuromuscular Diseases; Autoimmune Diseases; Immune System Diseases; Autoimmune Diseases of the Nervous System; Neurodegenerative Diseases; Paraneoplastic Syndromes, Nervous System; Nervous System Neoplasms; Paraneoplastic Syndromes; Neuromuscular Junction Diseases; Myasthenia Gravis; ublituximab
• Other Study ID Numbers: TG1101-MG201; 2025-524630-26-00 (Other Identifier: EU CT Number)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No