Shares of Viridian Therapeutics (NASDAQ:VRDN) dropped about 40% on Monday after the company released topline data from its Phase 3 REVEAL-1 study of elegrobart in patients with active thyroid eye disease, even though the treatment met its primary endpoint.
The trial produced a highly statistically significant treatment effect. Patients receiving elegrobart every four weeks (Q4W) and every eight weeks (Q8W) achieved proptosis responder rates of 54% and 63%, respectively, compared with 18% in the placebo group at week 24. In the Q4W dosing group, 51% of patients experienced complete resolution of diplopia, versus 16% among those receiving placebo.
The REVEAL-1 study enrolled 132 participants, who were evenly randomized into three groups: elegrobart Q4W, elegrobart Q8W and placebo. The trial met its primary endpoint of proptosis responder rate in the Q4W arm with strong statistical significance (p<0.0001). Average change from baseline in proptosis measured −2.33 mm for the Q4W group and −2.50 mm for the Q8W group, compared with −0.81 mm for placebo.
Elegrobart was generally well tolerated, with adverse events consistent with those typically associated with the anti-IGF-1R drug class. Rates of hearing-related issues were low in both treatment groups, with placebo-adjusted rates of 11.3% for Q4W and 2.3% for Q8W. All reported cases involved tinnitus, and none were linked to measurable hearing loss.
Viridian said it expects to file a Biologics License Application with the U.S. Food and Drug Administration for elegrobart in the first quarter of 2027. The company’s second pivotal Phase 3 study, REVEAL-2, which is evaluating elegrobart in patients with chronic thyroid eye disease, is still on schedule to deliver topline results in the second quarter of 2026.
At the end of the fourth quarter of 2025, Viridian reported $875 million in cash. The company’s other thyroid eye disease candidate, veligrotug, is currently under Priority Review by the FDA with a PDUFA target action date of June 30, 2026.