Innovent Biologics (HKEX: 01801) has initiated a first-in-human Phase I clinical trial of IBI3031, a bispecific antibody designed to simultaneously neutralize IGF-1R and TSHR in patients with active, moderate-to-severe thyroid eye disease. The trial's significance lies in its dual-target design: where approved therapy addresses only IGF-1R, IBI3031 adds co-targeting of the thyroid-stimulating hormone receptor, which drives the autoimmune component of the disease. Whether that combination confers meaningful clinical advantage over monospecific IGF-1R inhibition remains to be demonstrated in humans.
The randomized, double-masked, placebo-controlled Phase I study (NCT07622368) enrolls approximately 66 adults aged 18 to 75 with moderate-to-severe active thyroid eye disease. The trial proceeds in two stages: a single-ascending-dose phase testing subcutaneous and intravenous administration across five dose levels, followed by a multiple-ascending-dose phase involving three subcutaneous administrations at three dose levels. Primary endpoints cover safety and tolerability across standard domains, secondary endpoints include pharmacokinetic parameters, immunogenicity, and preliminary efficacy signals. Primary completion is anticipated in June 2027, according to the trial record.
IBI3031 targets two receptors that operate in parallel to drive orbital tissue expansion in thyroid eye disease. IGF-1R signaling in orbital fibroblasts promotes proliferation, hyaluronic acid secretion, and myofibroblast differentiation — processes that cause the proptosis and soft tissue changes characteristic of the condition. TSHR, stimulated by circulating autoantibodies in Graves' disease, activates the same fibroblast population through a distinct pathway and also drives thyroid hyperfunction. Preclinical data presented at the 2026 ARVO Annual Meeting, as reported by Innovent, indicated that simultaneous neutralization of both receptors inhibited orbital fibroblast proliferation and hyaluronic acid production more effectively than single-target blockade, and also attenuated thyroid cell hyperactivation. Those findings are preclinical and have not been validated in human studies.
The competitive context is directly relevant to interpreting Innovent's strategy. Teprotumumab (Tepezza, Amgen/Horizon Therapeutics), an FDA-approved anti-IGF-1R monoclonal antibody, established IGF-1R as a validated target in thyroid eye disease but is associated with hearing loss and infusion-related reactions, and is administered intravenously over approximately six months. Innovent's own monospecific anti-IGF-1R antibody, IBI311, has completed a Phase III trial in Chinese patients and has had a new drug application accepted by China's National Medical Products Administration; IBI3031 is positioned as a next-generation asset within the same program, with TSHR co-targeting intended to address the autoimmune driver that monospecific IGF-1R inhibition leaves intact.