Roughly two-thirds of people living with thyroid eye disease are in the inactive phase, where proptosis persists long after inflammation has settled, yet until recently the practical answer for most of them was surgery or nothing. Innovent’s RESTORE-3 trial, reported Wednesday, shows that IBI311 (SYCUME, teprotumumab N01 injection) cut that calculation: 60.4% of patients on the drug met the proptosis response threshold at week 24, against 23.5% on placebo, a 36.9-percentage-point gap that was statistically decisive (p = 0.0003).
The size of the eye movement also held up. The least squares mean reduction in proptosis was 1.88 mm in the IBI311 arm versus 0.88 mm with placebo, a 1.0 mm treatment difference (p < 0.0001). The 116-participant trial enrolled patients whose disease had been present a mean of 4.3 years and whose baseline proptosis averaged 22.16 mm, a somewhat milder starting point than in the TEPEZZA clinical program, though the response rates and absolute reductions in the two datasets run roughly parallel on an indirect comparison. The benefit extended to the non-study eye as well, where the response rate was 46.0% on drug versus 19.8% on placebo, suggesting bilateral rather than purely unilateral improvement.
SYCUME received NMPA approval in March 2025 and was added to China’s National Reimbursement Drug List on January 1, 2026. Its earlier approvals covered active TED; RESTORE-3 now supplies clinical evidence for the inactive phase, which the company frames as completing a full-disease-course profile. The IGF-1R mechanism is shared with teprotumumab (TEPEZZA), which the FDA approved in January 2020 and which has since generated data in low-activity, long-duration TED. In the U.S., the competitive picture has continued to move: Viridian’s veligrotug-vvze (Lumvoa) received FDA approval in June 2026 with labeling covering both active and chronic disease, though neither that drug nor TEPEZZA has a Chinese approval.
RESTORE-3 follow-up is ongoing and full data have not yet been published in peer review. The number to watch from here is whether Innovent files a supplemental indication with the NMPA for inactive TED on the basis of this readout, and how quickly NRDL reimbursement, already in place for the active indication, would extend to cover the broader patient group.
IBI311: the facts in one place
- Also written: SYCUME, Teprotumumab N01 Injection
- Sponsor: Innovent Biologics
- Mechanism: Recombinant anti-IGF-1R antibody that blocks IGF-1R signaling pathway to reduce inflammatory factors and inhibit orbital fibroblast activation
- Indication studied: Thyroid Eye Disease (TED), both active and inactive phases
- Phase: Phase 3 (RESTORE-3 completed for inactive TED; approved in China for active TED)
- Enrollment: 116
- Primary endpoint: Proptosis response rate at Week 24
- Headline result: RESTORE-3: proptosis response rate 60.4% vs. 23.5% for placebo at Week 24 in inactive TED
- Registry identifier: NCT05795621
- Current status: Approved in China for active TED and included in National Reimbursement Drug List as of January 1, 2026; Phase 3 RESTORE-3 completed with positive results for inactive TED
- NDA accepted by NMPA with priority review: May 2024
- Included in China National Reimbursement Drug List: January 1, 2026
- RESTORE-3 positive Phase 3 results announced: October 8, 2026
- RESTORE-1 trial published in JAMA Ophthalmology: November 1, 2025
Jon Napitupulu is Director of Media Relations at The Clinical Trial Vanguard. Jon, a computer data scientist, focuses on the latest clinical trial industry news and trends.
