Innovent designs first head-to-head trial of IGF-1R drug versus steroids in TED
The RESTORE-4 protocol pits teprotumumab N01 against intravenous glucocorticoid pulse therapy, the current first-line treatment, testing whether targeting IGF-1R beats steroids on proptosis at week 15.
Executive Summary
- A trial protocol describes a randomized, open-label Phase 4 study designed to compare an IGF-1R inhibitor directly against intravenous glucocorticoid pulse therapy in active thyroid eye disease, rather than against placebo.
- Glucocorticoid pulse therapy is the current first-line treatment for active, moderate-to-severe disease, but its effect on proptosis and diplopia is inconsistent and relapse is common, so a direct comparison addresses a real clinical uncertainty that placebo-controlled trials could not.
- The primary measure is a proptosis responder rate assessed early in treatment, with a broad set of secondary measures covering diplopia, quality of life, and safety, reflecting a disease that affects multiple domains beyond eye protrusion alone.
- IGF-1R inhibition is an active mechanism class in thyroid eye disease with multiple programs already in Phase 3, so the contribution here is a comparator choice, not a new biological hypothesis.
The stake
Thyroid eye disease is an autoimmune orbital disorder that can disfigure and threaten sight. Intravenous glucocorticoid (IVGC) pulse therapy is the current first-line treatment for active, moderate-to-severe disease, but the published protocol describes its effect on proptosis and diplopia as limited and inconsistent, with high relapse rates. IGF-1R inhibitors have emerged as a mechanism class that reduces proptosis and improves overall disease activity in earlier studies, but no trial had directly compared an IGF-1R inhibitor against IVGC until this design. Head-to-HeadHead-to-Head Comparison of an IGF-1R Inhibitor Versus Intravenous Glucocorticoid for Active Thyroid Eye Disease: Design of a Randomized Clinical Trial.Jul 14, 2026
Probability of SuccessBased on the AppliedXL Probability of Success model. For more information about the methodology, read the research here.
How it was done
RESTORE-4 (NCT07265258) is a multicenter, randomized, open-label, active-controlled Phase 4 trial in China sponsored by Innovent Biologics, planning to enroll approximately 92 adults with active, moderate-to-severe thyroid eye disease and baseline proptosis of at least 16 mm in the study eye. Participants are randomized 1:1 to intravenous teprotumumab N01 (a 10 mg/kg initial dose followed by 20 mg/kg at weeks 3, 6, 9, and 12) or IVGC pulse therapy (methylprednisolone 500 mg on day 1 and through week 5, tapering to 250 mg through week 11). The primary endpoint is the proportion of participants achieving a 2 mm or greater reduction in proptosis of the study eye at week 15, without a corresponding increase in the fellow eye. Twelve secondary measures track diplopia resolution, Clinical Activity Score, quality of life, and safety through week 48. NCT07265258+1A Study of Teprotumumab N01 in Subjects With Active Thyroid Eye DiseaseNCT07265258Head-to-Head Comparison of an IGF-1R Inhibitor Versus Intravenous Glucocorticoid for Active Thyroid Eye Disease: Design of a Randomized Clinical Trial.Jul 14, 2026
What the comparator choice tests
Framing the trial against IVGC rather than placebo is the design's substantive move. Placebo-controlled trials in this class have already shown IGF-1R inhibition reduces proptosis versus no treatment; what remains open is whether it beats, rather than simply exceeds, the regimen doctors already use first. The open-label design (no blinding) means proptosis measurement by Hertel exophthalmometer, an objective physical measurement, carries more weight than any activity score that depends on investigator or patient judgment. Head-to-HeadHead-to-Head Comparison of an IGF-1R Inhibitor Versus Intravenous Glucocorticoid for Active Thyroid Eye Disease: Design of a Randomized Clinical Trial.Jul 14, 2026
The competitive field
IGF-1R inhibition is not a novel mechanism in thyroid eye disease. At least ten industry programs are testing IGF-1R-directed therapies in the indication, including Viridian Therapeutics' veligrotug and VRDN-003, Minghui Pharmaceutical's MHB018A, Zai Lab's ZL-1109, and Sling Therapeutics' linsitinib, most in Phase 3. Innovent itself already runs a separate Phase 3 teprotumumab trial (NCT07113262) in the same indication with a primary completion date in December 2026. RESTORE-4's contribution is not a new target hypothesis but a design question: does the class's benefit hold up against the treatment it would need to displace in practice.
This analysis was produced using AI-assisted reporting systems, AppliedXL data, and official public records. These systems undergo editorial review, quality checks, and regular audits by human experts. Errors may still occur, as with any automated system. Always consult the linked primary sources. Read our AI Editorial Policy.