TG Therapeutics has announced the commencement of patient enrollment in a Phase 3 clinical trial evaluating subcutaneous BRIUMVI (ublituximab-xiiy) for adults with relapsing forms of multiple sclerosis (RMS). The milestone represents a critical advancement in the company's efforts to expand delivery options for its anti-CD20 monoclonal antibody therapy.
BRIUMVI is currently approved in the United States and several international territories as a one-hour intravenous infusion administered twice yearly following the initial dose. The new subcutaneous formulation aims to provide patients with a self-administered treatment option, addressing an unmet need in the multiple sclerosis therapeutic landscape.
Trial Design and Objectives
The Phase 3 study employs a non-inferiority, randomized, open-label, parallel-group, multicenter design to evaluate the pharmacokinetics, pharmacodynamics, safety, radiological and clinical effects of subcutaneous BRIUMVI compared to the established IV formulation. Participants will be randomized into three treatment arms: subcutaneous BRIUMVI administered every 8 weeks, subcutaneous BRIUMVI every 12 weeks, or the currently approved IV BRIUMVI dosing schedule.
The trial's primary endpoint focuses on demonstrating non-inferior exposure of subcutaneous BRIUMVI compared to IV BRIUMVI, specifically measuring area under the curve (AUC) at week 24. This pharmacokinetic approach will establish whether the subcutaneous formulation achieves comparable drug exposure to the proven intravenous therapy.
Market Opportunity and Strategic Impact
Michael S. Weiss, TG Therapeutics' Chairman and Chief Executive Officer, emphasized the potential market expansion opportunity, stating: "If successful, BRIUMVI would be the only anti-CD20 therapy to offer an IV healthcare provider administered option, as well as an at home subcutaneous self-administered option, providing greater flexibility and choice."
The company estimates that approximately 40% of the RMS CD20 dynamic market currently opts for self-injectable CD20 therapy, representing a significant untapped opportunity for BRIUMVI. This patient preference for self-administered treatments reflects broader trends toward convenient, home-based healthcare delivery.
Weiss projected that positive trial outcomes could support regulatory approval by 2028, stating: "As previously guided, and assuming a positive outcome, we believe data from this trial would support a potential approval in 2028, furthering our mission of delivering innovation and choice to people living with MS."
BRIUMVI's Unique Therapeutic Profile
BRIUMVI represents a novel monoclonal antibody that targets a unique epitope on CD20-expressing B-cells. The therapy's distinctive glycoengineered design removes certain sugar molecules normally expressed on antibodies, enabling efficient B-cell depletion at lower doses compared to conventional anti-CD20 therapies.
The drug is currently indicated for treating adults with RMS, including clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease. In the European Union and United Kingdom, BRIUMVI is approved for adult patients with RMS who have active disease defined by clinical or imaging features.
Commercial Performance and Growth Trajectory
BRIUMVI has demonstrated strong commercial momentum since its approval. In Q2 2025, the therapy contributed $138.8 million in U.S. net revenue, representing a 91% increase compared to 2024. Total company revenue reached $141.1 million in Q2 2025, marking a 92.1% year-over-year surge driven primarily by BRIUMVI's rapid market adoption.
Clinical data from the five-year extension of the ULTIMATE I & II trials revealed that 92% of patients remained free from disability progression, with an annualized relapse rate of 0.02 in year five. These long-term efficacy results, combined with a favorable safety profile including no observed cases of progressive multifocal leukoencephalopathy (PML), support BRIUMVI's positioning as a durable treatment option.
Global Expansion and Future Outlook
TG Therapeutics has expanded BRIUMVI's availability beyond the United States through partnerships, with approvals secured in the European Union, United Kingdom, Switzerland, and Australia. The company raised its 2025 global revenue guidance to $585 million, reflecting confidence in international adoption.
The subcutaneous development program represents part of TG Therapeutics' broader strategy to enhance patient convenience and expand market reach. The company has also advanced dosing optimization studies, including the ENHANCE trial demonstrating tolerability of single 600 mg infusions and 30-minute rapid infusions.
Multiple Sclerosis Disease Burden
Relapsing multiple sclerosis affects nearly 1 million people in the United States, with approximately 85% initially diagnosed with relapsing-remitting multiple sclerosis (RRMS). Worldwide, more than 2.3 million people have a multiple sclerosis diagnosis. The majority of RRMS patients eventually transition to secondary progressive multiple sclerosis, characterized by steadily worsening disability over time.
The subcutaneous BRIUMVI development program addresses the evolving needs of this patient population by potentially offering greater treatment flexibility and convenience while maintaining the therapeutic efficacy established with the intravenous formulation.
