Viridian shares tumble 38% despite Phase III elegrobart achieving up to 63% response
Viridian’s Phase III REVEAL-1 trial showed elegrobart delivered proptosis responder rates of 54% with four-week dosing and 63% with eight-week dosing versus 18% for placebo, yielding 2.33 mm and 2.5 mm reductions compared to 0.81 mm. Despite this and plans to file BLA in Q1 2027 after REVEAL-2 data due Q2 2026, the stock plunged 38%.
1. Phase III REVEAL-1 Efficacy Results
Viridian’s REVEAL-1 trial evaluated subcutaneous elegrobart in thyroid eye disease patients, showing a 54% proptosis responder rate and 2.33 mm average reduction with four-week dosing, and a 63% responder rate with a 2.5 mm reduction on eight-week dosing, versus 18% and 0.81 mm in placebo.
2. Stock Reaction
On March 30, the company’s shares tumbled 38% despite meeting primary efficacy endpoints and demonstrating statistical significance on secondary diplopia measures, reflecting investor concerns about market competitiveness and expectations for proptosis reduction rates.
3. Upcoming Milestones
Viridian plans to report REVEAL-2 data in Q2 2026 and intends to submit a Biologics License Application to the FDA for elegrobart in Q1 2027, advancing its half-life-extended monoclonal antibody targeting IGF-1R toward potential approval.