Elegrobart Shows Promising Results in Thyroid Eye Disease in Phase 3 trial
In a phase III trial, the investigational subcutaneous monoclonal antibody elegrobart demonstrated greater reduction in proptosis compared to placebo in patients with active thyroid eye disease. Additionally, 51% of patients experienced complete resolution of diplopia, highlighting its potential as an effective treatment option.
Elegrobart is a subcutaneously delivered, half-life-extended monoclonal antibody targeting the insulin-like growth factor-1 receptor (IGF-1R). REVEAL-1 evaluated two dosing regimens, every four weeks (Q4W) and every eight weeks (Q8W), compared with placebo.
“We are excited to report these results from REVEAL-1, the largest pivotal clinical trial conducted in active TED to date, which position elegrobart as potentially the first ever subcutaneous autoinjector treatment for TED,” said Steve Mahoney, President and Chief Executive Officer of Viridian Therapeutics. “REVEAL-1 met its primary endpoint with high statistical significance. Elegrobart treatment drove robust proptosis responses in a treatment regimen comprised of as few as three subcutaneous doses. Further, in the Q4W arm, we saw clinically meaningful diplopia responses and diplopia resolution. Currently, the only marketed treatment for TED requires eight intravenous infusions and, despite low market penetration, annualized in 2025 to approximately $2B in revenues. We believe there is a significant opportunity with subcutaneous elegrobart in TED, including the potential to expand the market as an at-home and self-administered treatment option, if approved.”
“Subcutaneous elegrobart showed rapid and clinically meaningful reductions in proptosis and diplopia in REVEAL-1 with a highly convenient, well-tolerated dosing profile,” said Prem Subramanian, MD, PhD, professor of ophthalmology at Colorado University Anschutz, and chief of neuro-ophthalmology at the Sue Anschutz-Rodgers Eye Center. “Patients are seeking more treatment choices for TED, and there remains a clear need for a more conveniently administered therapy. I am very encouraged to see the data for elegrobart and believe it has the potential to reach more TED patients than an intravenous therapy and to provide them with an attractive treatment option.”
Elegrobart REVEAL-1 Phase 3 Topline Results
REVEAL-1 assessed the efficacy and safety of subcutaneous Q4W or Q8W elegrobart versus placebo in patients with active TED. The study enrolled 132 patients, randomized 1:1:1 to elegrobart Q4W (n=44), elegrobart Q8W (n=44), and placebo (n=44).
REVEAL-1 Efficacy
REVEAL-1 was highly statistically significant on its primary endpoint of Q4W proptosis responder rate and the key secondary endpoint of Q4W proptosis mean change from baseline, each at week 24 as measured by exophthalmometry. REVEAL-1 also assessed elegrobart Q8W versus placebo and additional clinically relevant endpoints for both the Q4W and Q8W dosing arms. Detailed results are presented below:
REVEAL-1 Safety
Elegrobart was generally well-tolerated with a safety profile consisting of adverse events generally expected from the anti-IGF-1R class, the vast majority of which were mild. Rates of hearing impairment were low in both the Q4W and Q8W treatment arms (11.3% and 2.3% placebo-adjusted rates, respectively), and all reports were of tinnitus, none of which were associated with reductions in hearing.
Elegrobart on Track with a BLA Submission anticipated in Q1 2027
• Topline data from REVEAL-2 for patients with chronic TED, the second pivotal phase 3 clinical trial of elegrobart, remains on track to read out in Q2 2026.
• Viridian anticipates submitting a Biologics License Application (BLA) to the U.S. FDA for elegrobart in Q1 2027.
Veligrotug on Track with a PDUFA Target Action Date of June 30, 2026
• The veligrotug BLA is under Priority Review at the FDA with a Prescription Drug User Fee Act (PDUFA) target action date of June 30, 2026. Veligrotug also received both Breakthrough Therapy Designation and Priority Review from the FDA in 2025.
• Viridian is approaching full launch-readiness and is on track to support the PDUFA action date next quarter, with experienced teams in place across field sales, field medical affairs, market access, and patient services.
• Viridian anticipates the veligrotug commercial and medical affairs infrastructure will support a potential elegrobart launch, if approved, with limited incremental investment, providing an infrastructure to support multiple treatment options for patients within the Viridian TED portfolio.
