TG Therapeutics stock surged on June 3, 2026, after the company announced positive Phase 1 results for a subcutaneous formulation of BRIUMVI, raising the prospect of at-home quarterly dosing for relapsing multiple sclerosis patients.

Key Highlights

  • Phase 1 data showed subcutaneous BRIUMVI achieved mean bioavailability greater than 60% relative to IV administration with no new safety signals across over 100 patients.
  • PK modelling supports non-inferior drug exposure for the quarterly dosing regimen under evaluation in a fully enrolled Phase 3 trial, with top-line data expected year-end 2026 or early 2027.
  • If approved, subcutaneous BRIUMVI would be the first self-administered, at-home, quarterly anti-CD20 therapy for multiple sclerosis, potentially doubling the addressable market for the BRIUMVI Franchise.

A Clinical Catalyst With Commercial Implications

Shares of TG Therapeutics (Nasdaq: TGTX) gained approximately 11.65% on June 3, 2026, closing at $40.91 against a previous close of $36.64, as the company reported positive Phase 1 results for a subcutaneous formulation of BRIUMVI (ublituximab-xiiy). TG Therapeutics is a commercial-stage biopharmaceutical company headquartered in Morrisville, North Carolina, focused on treatments for B-cell mediated diseases, with BRIUMVI as its flagship approved product for relapsing forms of multiple sclerosis. The company reported Net Income of $447.2 million and a net profit Margin of 72.6% in fiscal year 2025, with 352 employees and a Market Capitalisation of approximately $6.26 billion. The session snapped a five-session losing streak and rekindled bullish investor sentiment.

What the Phase 1 Data Shows

The Phase 1 trial evaluated a high-concentration 400 mg per 2 mL subcutaneous formulation against the approved IV regimen across over 100 patients and more than 225 injections. Subcutaneous BRIUMVI demonstrated mean bioavailability exceeding 60% relative to IV. Pharmacokinetic modelling supports non-inferior drug exposure for the quarterly dosing regimen, with a geometric mean ratio of 1.21 and a 90% confidence interval lower bound of 1.15, exceeding the non-inferiority threshold of 0.80. B-cell depletion was consistent with IV BRIUMVI, injection-site reactions occurred in fewer than 5% of patients, and no new safety signals were observed.

The Market Expansion Thesis

The commercial significance of the Phase 1 results lies in the potential to expand the BRIUMVI addressable market. Currently administered via IV infusion in a clinical setting, a self-administered subcutaneous option delivered quarterly at home would open a distinct patient segment within the anti-CD20 therapy market. CEO Michael S. Weiss characterised the potential as nearly doubling the addressable market opportunity for the BRIUMVI franchise. With approximately 1 million people living with MS in the United States, roughly 85% initially diagnosed with relapsing-remitting disease, the commercial stakes are significant. A potential approval pathway is projected for 2028. CEO Weiss is also scheduled at a Goldman Sachs Healthcare Conference fireside chat on June 9, a near-term engagement catalyst.

Valuation and Risk Considerations

TGTX trades at a P/E of 14.30 on EPS of $2.86, a reasonable multiple relative to the company's demonstrated profitability. The 52-week range of $25.28 to $44.65 reflects ongoing clinical risk. A failure to meet the primary non-inferiority endpoint or adverse safety signals in Phase 3 would materially alter the market expansion thesis.

Conclusion

TG Therapeutics' Phase 1 subcutaneous BRIUMVI data strengthens the clinical rationale for a delivery format that could meaningfully expand the franchise's commercial reach. The Investment case now hinges on Phase 3 top-line data expected by year-end 2026 or early 2027, and the regulatory pathway that follows.