Open-Label Extension Study of MHB018A in Patients With Thyroid Eye Disease

A Phase III, Multicenter, Open-Label Extension Study to Evaluate the Efficacy and Safety of MHB018A Injection in Subjects With Thyroid Eye Disease

This is a multicenter, open-label extension (OLE) study of MHB018A in subjects with moderate-to-severe TED.

Study Overview

• Status: Not yet recruiting
• Conditions: Thyroid Eye Disease (TED)
• Intervention / Treatment: Drug: MHB018A injection

Detailed Description

The primary objective of this study is to evaluate the improvement in proptosis from baseline (defined as the most recent measurement prior to the first dose in this study) following treatment with MHB018A Injection in subjects with active or chronic TED who previously received placebo in either the MHB018A-P-304 or MHB018A-P-305 studies, and the safety and tolerability of MHB018A Injection in TED subjects.

• Study Type: Interventional
• Enrollment (Estimated): 219
• Phase: Phase 3

Contacts and Locations

• Study Contact: Name: CMO/ Senior Vice President of R&D; Phone Number: 86 0571-86963293; Email: jwshi@minghuipharma.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Subjects voluntarily participating in the study and signing the informed consent form;
2. Aged 18-75 years (inclusive), of any gender;
3. Completed the 24-week double-blind treatment period in either the MHB018A-P-301 or MHB018A-P-302 study, and within 28 days after Week 24 visit of the previous study when enrolled in this OLE study (does not apply to subjects who meet the relapse criteria during the safety follow-up period).
4. Proptosis non-responder at Week 24 visit in the double-blind treatment period of either the MHB018A-P-301 or MHB018A-P-302 study (defined as a <2 mm reduction from baseline in the study eye, or a ≥2 mm reduction in the study eye accompanied by a ≥2 mm worsening from baseline in proptosis of the fellow eye), and/or who meet the retreatment criteria for relapse during the safety follow-up period.
5. Does not require immediate surgical ophthalmological intervention, and no corrective surgery/orbital radiotherapy is planned during the study.
6. Diabetic subjects must have well-controlled stable disease.
7. Sufficient bone marrow and organ function.
8. Eligible subjects of childbearing potential (male and female) must agree to use reliable contraceptive methods; female subjects of childbearing potential must have a negative blood pregnancy test within 7 days before the first use of the study drug and must not be breastfeeding.

9. Subject is willing and able to comply with the prescribed treatment protocol and evaluations for the duration of the study.

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Exclusion Criteria:

1. Decreased best corrected visual acuity due to optic neuropathy as defined by a decrease in vision within the last 6 months of two lines of Snellen chart, new visual field defect or color defect secondary to optic nerve involvement.
2. Corneal decompensation unresponsive to medical management.
3. Free thyroxine (FT4) and free triiodothyronine (FT3) levels <50% above or below the normal reference range at screening.
4. Received any treatment for TED, intravenous corticosteroids, immunosuppressive agents, investigational drug from the last visit of the MHB018A-P-301 or MHB018A-P-302 trial until participation in this study.
5. Identified pre-existing ophthalmic disease that would preclude study participation or complicate interpretation of the study results.
6. Acute cardiovascular disease history or treatment within 6 months before the first dose from the last visit of the MHB018A-P-301 or MHB018A-P-302 trial until participation in this study.
7. Presence of poorly controlled hypertension with systolic blood pressure ≥ 160 mmHg or diastolic blood pressure ≥ 100 mmHg; Renal artery stenosis.
8. Pregnant or lactating women.
9. Tinnitus or other hearing impairment.

10. Poor compliance or severe systemic disease history or other reasons that make the subject unsuitable for participation in this clinical study.

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Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: MHB018A Injection; Subcutaneous injections of MHB018A injection, 450mg once every 4 weeks (q4w).	Drug: MHB018A injection; MHB018A 450mg for subcutaneous injection once every 4 weeks (Q4W)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Proptosis Responder Rate at Week 24	The proptosis response rate at Week 24 in the study eye for subjects with active or chronic TED who received MHB018A placebo in either the MHB018A-P-301 or MHB018A-P-302 studies: the proportion of subjects achieving a reduction of ≥2 mm in proptosis from baseline (defined as the most recent measurement prior to the first dose in this study) in the study eye, without deterioration in the other eye (defined as an increase in proptosis of ≥2 mm).	Week 24

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Overall response rate	The percentage of subjects with ≥2-points in Clinical Activity Score (CAS) reduction and ≥2 mm reduction in proptosis from baseline, provided there is no corresponding deterioration (≥2-points/mm increase) in CAS or proptosis in the fellow eye.	Week 24
Change in proptosis	Change from baseline in proptosis in the study eye as measured by exophthalmometer at Week 24	Baseline, up to Week 24
Diplopia response rate	The percentage of subjects with a reduction in diplopia severity by ≥1 grade.	Week 24
Incidence of Adverse Events (AEs) During Treatment	Including Treatment-Emergent Adverse Events (TEAEs), Serious Adverse Events (SAEs), and AEs leading to early study withdrawal, along with laboratory tests, 12-lead ECGs, vital signs, and physical examinations.	Up to Week 24 and at end-of-trial (EOT) visit
TED relapse rate	TED relapse rate from treatment discontinuation to relapse (for subjects with active or chronic TED who previously received and completed 24 weeks of MHB018A Injection treatment in either the MHB018A-P-301 or MHB018A-P-302 study, meet the disease relapse enrollment criteria for this study during the safety follow-up period, and receive retreatment with MHB018A Injection)	From baseline up to Week 24
TED relapse time	TED relapse time from treatment discontinuation to relapse (for subjects with active or chronic TED who previously received and completed 24 weeks of MHB018A Injection treatment in either the MHB018A-P-301 or MHB018A-P-302 study, meet the disease relapse enrollment criteria for this study during the safety follow-up period, and receive retreatment with MHB018A Injection)	Up to Week 24 and at end-of-trial (EOT) visit
Change in Quality of Life (GO-QOL) Scores	The mean change in scores from the Graves' Ophthalmopathy Quality of Life questionnaire compared to baseline. The GO-QoL is a self-filled questionnaire containing 16 items. The raw scores for items 1-8 and items 9-16 are summed separately, each yielding a total raw score ranging from 8 to 24. Each raw score is then transformed into a 0-100 scale using the following formula: Total Score = (Raw Score - 8) ÷ 16 × 100. Higher scores indicate better quality of life.	Up tp Week 24
Pharmacokinetic Parameter Trough Concentration for MHB018A	Trough concentration (Ctrough) will be assessed using non-compartmental methods in participants randomized to the MHB018A group.	Up tp Week 24
Percentage of subjects with CAS of 0 or 1	The percentage of subjects with a CAS (Clinical Activity Score) of 0 or 1 in the study eye/target eye. CAS ranges from 0 to 7, while higher scores mean a worse outcome.	Week 24
Change in CAS	The mean change from baseline to Week 24 in the CAS (Clinical Activity Score) in the study eye/target eye. CAS ranges from 0 to 7, while higher scores mean worse outcome.	Week 24

Collaborators and Investigators

• Sponsor: Minghui Pharmaceutical (Hangzhou) Ltd

Study record dates

Study Major Dates

• Study Start (Estimated): July 1, 2027
• Primary Completion (Estimated): January 1, 2030
• Study Completion (Estimated): January 1, 2031

Study Registration Dates

• First Submitted: May 27, 2026
• First Submitted That Met QC Criteria: May 27, 2026
• First Posted (Actual): June 2, 2026

Study Record Updates

• Last Update Posted (Actual): June 4, 2026
• Last Update Submitted That Met QC Criteria: June 2, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Endocrine System Diseases; Genetic Diseases, Inborn; Autoimmune Diseases; Immune System Diseases; Eye Diseases; Eye Diseases, Hereditary; Graves Disease; Exophthalmos; Orbital Diseases; Goiter; Hyperthyroidism; Thyroid Diseases; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Graves Ophthalmopathy
• Other Study ID Numbers: MHB018A-P-306

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No