Viridian Therapeutics Reports Positive Phase 3 Data for Elegrobart in Thyroid Eye Disease

Key Highlights

• REVEAL-1 trial met its primary endpoint with highly statistically significant results for proptosis responder rate (PRR).
• Elegrobart administered every four weeks (Q4W) and eight weeks (Q8W) showed PRR of 54% and 63% respectively, versus 18% for placebo at week 24.
• Complete resolution of diplopia (double vision) achieved in 51% of Q4W patients versus 16% for placebo.
• Elegrobart demonstrated strong safety profile with low rates of hearing impairment and adverse events mainly mild and consistent with anti-IGF-1R class.
• Second pivotal Phase 3 trial (REVEAL-2) in chronic TED on track for topline readout in Q2 2026; BLA submission anticipated in Q1 2027.
• Viridian ended 2025 with \$875 million in cash; expects cash, near-term milestones, and future commercial revenues to fund operations through profitability.
• Conference call and webcast scheduled for March 30, 2026, at 8:00 a.m. ET.

Clinical Data Details

The REVEAL-1 Phase 3 trial is the largest pivotal clinical trial conducted in active thyroid eye disease (TED) to date and positions Elegrobart as the potentially first subcutaneous autoinjector treatment for TED. Elegrobart is a subcutaneously delivered, half-life-extended monoclonal antibody targeting the IGF-1R receptor.

• Trial evaluated two dosing regimens: Q4W (every four weeks) and Q8W (every eight weeks), compared to placebo.
• 132 patients enrolled, randomized 1:1:1 (44 per group).
• Primary endpoint: Proptosis responder rate (PRR) at week 24 (FDA criteria):
  • Q4W: 54%
  • Q8W: 63%
  • Placebo: 18%
  • p-values: < 0.0001 for both Q4W and Q8W, indicating high statistical significance
• EMA Overall Responder Rate (ORR):
  • Q4W: 51%
  • Q8W: 58%
  • Placebo: 16%
  • p-values: 0.0001 (Q4W), <0.0001 (Q8W)
• Proptosis mean change from baseline (exophthalmometry):
  • Q4W: -2.33 mm
  • Q8W: -2.50 mm
  • Placebo: -0.81 mm
  • p-values: <0.0001 for both arms
• Diplopia responder rate:
  • Q4W: 71% (p=0.0009)
  • Q8W: 54% (p=0.05)
  • Placebo: 32%
• Diplopia complete resolution:
  • Q4W: 51% (p=0.0013)
  • Q8W: 28% (p=0.14)
  • Placebo: 16%
• Proptosis responder rate by MRI:
  • Q4W: 50% (p<0.0001)
  • Q8W: 36% (p<0.0001)
  • Placebo: 2%
• Proptosis mean change from baseline by MRI:
  • Q4W: -2.04 mm
  • Q8W: -1.99 mm
  • Placebo: -0.22 mm
  • p-values: <0.0001
• Clinical Activity Score (CAS) reduction to 0 or 1:
  • Q4W: 57% (p=0.24)
  • Q8W: 69% (p=0.03)
  • Placebo: 50%

Safety Profile

• Elegrobart was generally well-tolerated.
• Adverse events were mild and consistent with anti-IGF-1R class.
• Low rates of hearing impairment: Q4W 11.3%, Q8W 2.3% (placebo-adjusted rates).
• Reports of tinnitus were not associated with reductions in hearing.

Commercial and Regulatory Outlook

• REVEAL-2: Second pivotal Phase 3 trial in chronic TED is on track for topline data in Q2 2026.
• BLA submission for Elegrobart expected in Q1 2027.
• Viridian ended Q4 2025 with \$875 million in cash, and expects funding from cash, royalty milestones, and anticipated commercial revenues from Veligrotug and Elegrobart (if approved) to support operations through profitability.
• Veligrotug (another anti-IGF-1R candidate) BLA is under Priority Review with a PDUFA target action date of June 30, 2026. It has received Breakthrough Therapy Designation and Priority Review from the FDA in 2025.
• Viridian is approaching full launch-readiness for Veligrotug and expects to leverage its commercial infrastructure for Elegrobart launch, if approved, with limited incremental investment.

Potential Market Impact

The only currently marketed treatment for TED requires eight intravenous infusions and generated approximately \$2 billion in revenues in 2025, with relatively low market penetration. Elegrobart’s subcutaneous administration could dramatically expand the market by offering a convenient, at-home, self-administered option, if approved. This could be a significant commercial opportunity for Viridian.

Investor Considerations

• Positive REVEAL-1 topline results strengthen Viridian’s position in TED treatment market.
• Potential first subcutaneous autoinjector for TED could drive rapid adoption and expand patient access.
• Upcoming regulatory milestones (REVEAL-2 topline data, BLA submissions, and PDUFA dates) represent significant potential catalysts for share price movement.
• Strong cash position and anticipated funding through profitability reduces financing risk.
• Viridian’s pipeline includes additional programs targeting autoimmune and rare diseases, expanding future growth potential.

Conference Call Information

Viridian will host a conference call at 8:00 a.m. ET on March 30, 2026, to discuss the REVEAL-1 topline data. The dial-in number for domestic participants is (800) 715-9871 and +1 (646) 307-1963 for international participants. Conference ID: 7373356. A live webcast and archive will be available on the Viridian Therapeutics website.

About Viridian Therapeutics

Viridian is a biopharmaceutical company focused on best-in-class medicines for serious and rare diseases, with expertise in antibody discovery and protein engineering. The company is advancing anti-IGF-1R candidates for TED, anti-TSHR programs for TED and Graves’ disease, and a portfolio of FcRn inhibitors (VRDN-006, VRDN-008) targeting autoimmune diseases.

Disclaimer

This article contains forward-looking statements, which are subject to risks and uncertainties. Actual results may differ materially from those expressed or implied in these statements. Investors should review Viridian’s filings with the SEC, including risk factors in the most recent Annual Report and Quarterly Reports. This article is for informational purposes only and does not constitute investment advice.

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