Evaluate the Safety of HBM9161 (HL161) Subcutaneous Injection in Patients With Generalized Myasthenia Gravis

Study Overview
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Brief Summary
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The primary study objective is to evaluate medium- and long-term safety of HBM9161 in combination with background treatment for gMG patients through the observation on adverse events and laboratory abnormalities during study period.

Official Title
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A Long-term Open-label Extension Study to Evaluate the Safety of HBM9161 (HL161) Subcutaneous Injection in Patients With Generalized Myasthenia Gravis

Conditions
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Myasthenia Gravis

Intervention / Treatment
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* Drug: HBM9161 Injection (680mg)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Completed the HBM9161.3 Phase 3 study Signed written informed consent. Suitable for continued treatment with HBM9161 as judged by the investigator. Female patients of childbearing potential and male patients with female partners of childbearing potential can participate in this study, but reliable contraceptive measures must be taken (such as physical barrier contraception (patients and their partners), contraceptive pills or patches, spermicide and barrier or intrauterine device). Up to 60 days after the last dose. A negative urine pregnancy at baseline must be observed for women of childbearing age. Exclusion Criteria: Had received any other clinical study drug since the administration of the study drug in the 9161.3 Phase 3 study. Females who are pregnant or lactating or planning to become pregnant during the study period, or females of childbearing potential who are not using an effective method of contraception.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: HBM9161 Drug Product (680mg)<br>HBM9161 680mg: subcutaneous injection, 6 times per treatment cycle, once a week; the second cycle of treatment may start 4 weeks after the last dose of the previous treatment cycle; if the disease state is still stable 4 weeks after the last dose, the observation can be continued until the disease activity is aggravated (improvement of MG-ADL < 3 points compared with the previous treatment cycle), and the next treatment cycle can start. The dose may be reduced to 340 per investigator's discretion. Return to the dose of 680 mg is not permitted after a dose reduction is made. | Drug: HBM9161 Injection (680mg)<br>* HBM9161 Injection<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of AEs during the study | Incidence of AEs | during the study，up to 24 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Proportion of patients with sustained improvement | Sustained reduction defined as MG-ADL score improved by ≥ 3 points from baseline for at least 4 consecutive weeks during the 9-week treatment cycle | during each treatment cycle (5-week treatment period + 4-week observation period, from the first dose of the cycle to Day 64 of the cycle) | 
| During the 24-week study, proportion of time that MG-ADL improved from baseline by 3 or more points |  | during the study，up to 24 weeks | 
| Proportion of time remained in Minimal Symptom Expression | from baseline to Week 24, percentage of time MG-ADL score being 0 or 1 | during the study，up to 24 weeks | 
| Improvement of patients' quality of life | Improvement of patients' quality of life | during the study，up to 24 weeks | 
| Incidence and duration of serum anti-HBM9161 antibodies and neutralizing antibodies | Incidence and duration of serum anti-HBM9161 antibodies and neutralizing antibodies | during the study，up to 24 weeks |