FRI545 Durability Of Treatment Response With VRDN-001, A Full Antagonist Antibody To IGF-1 Receptor, In Patients With Thyroid Eye Disease (TED): Phase 1/2 Clinical Study

Disclosure: R. Douglas: Consulting Fee; Self; Horizon Therapeutics, Viridian Therapeutics. Research Investigator; Self; Viridian Therapeutics Inc., Horizon Therapeutics. S. Ugradar: Consulting Fee; Self; Viridian Therapeutics Inc. K. Cockerham: Advisory Board Member; Self; Viridian Therapeutics Inc., Horizon Therapeutics. Research Investigator; Self; Viridian Therapeutics Inc. Speaker; Self; Horizon Therapeutics. R.E. Turbin: Advisory Board Member; Self; Horizon Therapeutics. Research Investigator; Self; Viridian Therapeutics Inc. Stock Owner; Self; Viridian Therapeutics Inc. R. Tang: Consulting Fee; Self; Viridian Therapeutics Inc. Research Investigator; Self; Viridian Therapeutics Inc., Horizon Therapeutics. N. Nijhawan: Research Investigator; Self; Viridian Therapeutics Inc. D.J. O’Shaughnessy: Employee; Self; Viridian Therapeutics Inc. R.M. Summerfelt: Employee; Self; Viridian Therapeutics Inc. A. She: Employee; Self; Viridian Therapeutics Inc. B. Katz: Employee; Self; Viridian Therapeutics Inc. Introduction: Clinical and preclinical evidence demonstrate IGF-1 receptor (IGF-1R) antagonism reduces TED-related inflammation and proptosis. VRDN-001, a subnanomolar affinity, full antagonist antibody to IGF-1R, is being evaluated in a phase 1/2 double-masked RCT (NCT05176639) at 3, 10, or 20 mg/kg administered intravenously. Results from the first cohort of TED patients (10 mg/kg) are presented here. Methods: Adults with active moderate-to-severe TED and clinical activity score (CAS) ≥4 were randomized to 2 infusions 3 weeks apart of either 10 mg/kg VRDN-001 or placebo (3:1). Safety, tolerability, and efficacy through 12 weeks were assessed. Endpoints included overall responder rate (% of patients with ≥2 mm reduction in proptosis and ≥2 point reduction in CAS), proptosis responder rate (% of patients with ≥2 mm reduction), change from baseline in proptosis and CAS, proportion of patients with CAS decrease to 0 or 1, and diplopia resolution. Results: Baseline characteristics were similar between VRDN-001 (n=6) and placebo (n=2). After 2 infusions, at 6 weeks, the overall responder rate was 83% (5/6; VRDN-001) vs. 0% (0/2; placebo). Proptosis responder rate was 83% (5/6; VRDN-001) vs. 50% (1/2; placebo). Mean proptosis decreased by 2.4 mm (VRDN-001) vs. 1.0 mm (placebo). MRI analysis of proptosis, available for 4 of 6 drug-treated patients, confirmed proptosis improvement in each; MRI analysis showed slight worsening of proptosis in both placebo patients. CAS decreased to 0 or 1 for 83% (5/6; VRDN-001) vs. 0% (0/2; placebo), with mean decreases of 4.3 (VRDN-001) and 1.5 (placebo). In patients presenting with diplopia, complete resolution occurred for 75% (3/4; VRDN-001) vs. 0% (0/1; placebo). Durability of response in the 5 VRDN-001 treatment responders at 6 weeks persisted through 12 weeks: 80% (4/5) maintained overall responder status and 80% (4/5) maintained proptosis responder status, with mean reduction in proptosis at week 12 of 2.2 mm for all 6 drug-treated patients; MRI analysis confirmed the maintained response for all 4 of the drug-treated patients for whom scans were available. Mean CAS reduction remained consistent (4.2 at Week 12 vs. 4.3 at Week 6) and 80% (4/5) maintained a CAS of 0 or 1. All 4 patients with baseline diplopia had diplopia resolution at Week 12. VRDN-001 was well-tolerated through 12 weeks. AEs were mostly mild, with no severe or serious AEs reported. Conclusions: Two infusions of 10 mg/kg VRDN-001 were well tolerated in this cohort of TED patients, and the rapid, clinically meaningful improvement across all efficacy measures by 6 weeks was sustained through 12 weeks. Further, these results were achieved with a lower dose and fewer treatments than in prior RCTs of other anti-IGF-1R antibodies. Results from the additional 3 mg/kg and 20 mg/kg cohorts may extend these findings and define potential VRDN-001 treatment regimens. Presentation: Friday, June 16, 2023