Chinese biopharmaceutical company Innovent Biologics Inc (HKEX:01801) announced on Thursday that its recombinant anti-insulin-like growth factor 1 receptor (IGF-1R) antibody, SYCUME (Teprotumumab N01 Injection, R&D code: IBI311), has achieved its primary endpoint at Week 24 in a multicentre, randomised, double-blind, placebo-controlled Phase 3 clinical study.

The RESTORE-3 study involved 116 Chinese participants with inactive thyroid eye disease (TED), who were randomised in an approximate 2:1 ratio to receive either SYCUME or placebo.

In the study, SYCUME demonstrated efficacy in reducing proptosis in participants with inactive TED, with a favourable safety profile.

SYCUME is the first IGF-1R antibody drug in China and the second approved globally.

At Week 24, the primary endpoint of the proptosis response rate in the study eye was significantly higher in the IBI311 group compared with the placebo group.

Additionally, the least squares mean (LS Mean) change from baseline in study eye proptosis distance in the IBI311 group was -1.88 mm, demonstrating statistically significant superiority over placebo (-0.88 mm). The proptosis response rate in non-study eyes was higher in the IBI311 group than in the placebo group (46.0% vs. 19.8%). The LS Mean change from baseline in proptosis distance in non-study eyes reached -1.77 mm in the IBI311 group versus -0.91 mm in the placebo group, consistent with the trend observed in study eyes.

During the double-blind treatment and follow-up period, IBI311 showed good safety and tolerability.