Innovent Biologics announced October 8, 2026, that its phase 3 RESTORE-3 study met its primary endpoint, with teprotumumab N01 injection (Sycume; R&D code IBI311) significantly reducing proptosis in Chinese patients with inactive thyroid eye disease (TED).¹ At week 24, 60.4% of patients receiving the recombinant anti-insulin-like growth factor 1 receptor (IGF-1R) antibody achieved a proptosis response in the study eye, compared with 23.5% of those on placebo, a 36.9 percentage point difference (P = 0.0003).¹
Key facts
- Drug: Teprotumumab N01 (Sycume; R&D code IBI311; Innovent Biologics)
- Class: Recombinant anti-IGF-1R monoclonal antibody
- Indication studied: Inactive thyroid eye disease (bilateral Clinical Activity Score ≤2)
- Trial: RESTORE-3; phase 3; randomized, double-blind, placebo-controlled; n=116
- Primary endpoint met: Proptosis response rate, 60.4% vs 23.5% (P = 0.0003)
- Secondary endpoints: Proptosis change -1.88 mm vs -0.88 mm; non-study eye response 46.0% vs 19.8%
- Safety: Mostly mild to moderate treatment-emergent adverse events; no new safety signals
- Current approval: NMPA-approved for TED since March 2025; added to NRDL January 1, 2026
"Results from this trial confirm that SYCUME yields robust and clinically meaningful reductions in proptosis even in patients with chronic, inactive TED," said Zhongyan Shan, MD, PhD, of the First Hospital of China Medical University and lead principal investigator of the study, in a company press release.¹ "This not only validates the therapeutic value of targeting IGF-1R in long-duration inactive TED but also offers tens of thousands of chronic TED sufferers and clinicians a novel non-surgical treatment paradigm."
What else did the RESTORE-3 trial show?
RESTORE-3 randomized 116 participants in an approximate 2:1 ratio to teprotumumab N01 or placebo, with a mean disease duration of 4.3 years and baseline mean study-eye proptosis of 22.16 mm.¹,² The key secondary endpoint, which was least squares mean change in study-eye proptosis at week 24, favored teprotumumab N01 over placebo (-1.88 mm vs -0.88 mm; treatment difference, -1.00 mm; P < 0.0001).¹ Proptosis response also improved in non-study eyes (46.0% vs 19.8%; P = 0.0071).¹ Most treatment-emergent adverse events were mild to moderate, with no new safety signals. Follow-up is ongoing, with complete data planned for future conferences or journals, the company stated in its release.¹
How does Sycume work, and what is its regulatory history in China?
Teprotumumab N01 blocks IGF-1R signaling, reducing downstream inflammatory factors and limiting orbital fibroblast differentiation into adipocytes or myofibroblasts. The National Medical Products Administration approved Sycume for TED in March 2025, making it China's first approved IGF-1R antibody and the second worldwide after teprotumumab (Tepezza), according to the company.¹ Sycume was added to China's National Reimbursement Drug List (NRDL) on January 1, 2026.¹
"As the first targeted therapy for TED approved and successfully incorporated into the NRDL in China, SYCUME has already benefited a vast number of TED patients,” said Lei Qian, MD, PhD, Innovent's chief R&D officer for general biomedicine, in the release.¹ “With these positive [phase 3] trial results, SYCUME now achieves comprehensive disease coverage ranging from 'early acute control' to 'chronic phase tissue remodeling.' … We will work closely with medical experts to rapidly translate these clinical findings into standard clinical practice, benefiting a broader patient population and elevating the overall standard of TED diagnosis and care in China."
