MHB018A shows clinical activity in active and chronic thyroid eye disease

Updated Phase I/II data presented at ENDO 2026 suggest subcutaneous MHB018A was associated with proptosis and diplopia responses in patients with active and chronic thyroid eye disease.

MHB018A, a novel subcutaneously administered VHH antibody targeting insulin-like growth factor 1 receptor, has shown clinical activity in both active and chronic thyroid eye disease (TED), according to updated Phase I/II data presented at ENDO 2026.¹

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TED is an autoimmune inflammatory disorder affecting the orbit and is most commonly associated with Graves’ disease. It can cause eyelid retraction, proptosis, diplopia, ocular surface disease and, in more severe cases, dysthyroid optic neuropathy.²,³ For ophthalmologists, TED management often involves monitoring disease activity, assessing visual function and ocular motility, managing exposure-related symptoms and coordinating care with endocrinology and oculoplastics teams. Although treatment options have advanced, there remains a need for effective and practical therapies that can address disease burden across both active and chronic stages.

MHB018A is designed to inhibit IGF-1R signalling, including IGF-1- and IGF-2-mediated pathways. The Phase I/II study included a double-blind, randomized phase and an open-label expansion. In the randomized phase, patients with active TED were assigned to MHB018A or placebo across three dose cohorts: 300 mg every 4 weeks, a 600 mg loading dose followed by 300 mg every 4 weeks, or 450 mg every 4 weeks. The expansion phase evaluated fixed 300 mg and 450 mg doses in patients with active or chronic TED.¹

Overall, 71 patients with active TED and 33 patients with chronic TED were enrolled. Patients with active TED received three doses over 12 weeks. At Week 12, proptosis response rates were 56% with 300 mg, 50% with the 600 mg loading dose followed by 300 mg, and 81% with 450 mg every 4 weeks. Secondary efficacy endpoints also favoured the 450 mg dose.¹

At the 450 mg every 4 weeks dose, patients with active TED achieved a mean proptosis change of -2.83 mm at Week 12. A Clinical Activity Score of 0 or 1 was reported in 84% of patients, while overall response, diplopia response and complete diplopia resolution were reported in 78%, 85% and 59% of patients, respectively.¹

In patients with chronic TED treated with 450 mg every 4 weeks, MHB018A achieved a proptosis response of 76% at Week 24, with a mean change from baseline of -2.65 mm. Among patients with diplopia at baseline, 61% achieved a diplopia response and 50% had complete diplopia resolution.¹

MHB018A was generally well tolerated across the study population. Most adverse events were mild and consistent with the expected effects of IGF-1R inhibition. No serious adverse events or severe hearing-related adverse events were reported, and all hearing-related adverse events were Grade 1, with no severe or permanent hearing damage observed.¹,⁴

Guoqing Cao, PhD, Chief Executive Officer of Minghui Pharmaceutical, said the Phase I/II results showed improvements in proptosis and diplopia across active and chronic TED, as well as a high proportion of patients with active TED achieving low inflammatory activity scores. He also highlighted the potential role of subcutaneous administration in future clinical use.⁴

MHB018A is currently being evaluated in ongoing Phase III trials in China, with topline results anticipated in Q3 2026. Global Phase III trials have also been initiated, with first patient enrolment targeted for Q4 2026.⁴

References

1. ORF49-08. Subcutaneous MHB018A, a Novel Anti-IGF-1R VHH Antibody, for Thyroid Eye Disease (TED): Results from a Phase 1/2 Study in Patients with Active and Chronic TED. Presented at ENDO 2026, Chicago, IL, USA, June 13–16, 2026.
2. Shah SS, Patel BC. Thyroid Eye Disease. StatPearls. Treasure Island, FL: StatPearls Publishing; 2023.
3. Burch HB, Perros P, Bednarczuk T, et al. Management of thyroid eye disease: a Consensus Statement by the American Thyroid Association and the European Thyroid Association. Eur Thyroid J. 2022;11(6).
4. Minghui Pharmaceutical. Minghui Pharmaceutical Presents Compelling Phase I/II Results for MHB018A, a Novel Subcutaneous Anti-IGF-1R Antibody for Thyroid Eye Disease, in an Oral Presentation at ENDO 2026, the Endocrine Society’s Annual Meeting. Press release. Available at: https://www.prnewswire.com/news-releases/minghui-pharmaceutical-presents-compelling-phase-iii-results-for-mhb018a-a-novel-subcutaneous-anti-igf-1r-antibody-for-thyroid-eye-disease-in-an-oral-presentation-at-endo-2026-the-endocrine-societys-annual-meeting-302799997.html (accessed June 15, 2026).