A Study to Evaluate the Efficacy, Safety and PD and PK of HBM9161 in MG Patients
A Study to Evaluate the Efficacy, Safety and PD and PK of HBM9161 in MG Patients
Primary Objectives: To investigate the efficacy of HBM9161 in patients with attack of MG in
 China
This is a multicenter, randomized, double-blind and placebo-controlled study. The
 investigational drug is HBM9161 injection, and the indication is MG.

 The subjects will be randomized to three dose groups (340mg, 680mg and placebo) for a 6
 weeks' double-blind treatment period followed by an open-label extension treatment period.
 The study will investigate the safety, efficacy and pharmacodynamic and pharmacokinetic of
 HBM9161 in patients with attack of MG in China.
Inclusion Criteria:

 1. Signed Informed Consent Form.

 2. Male or female ≥ 18 years of age.

 3. A female participant is eligible to participate if she is of:

 1. Non-childbearing potential (physically infertile, including women who have been
 menopausal for 2 years or more);

 2. Childbearing potential, negative serum pregnancy test results at screening
 visits, and agree to consistently use acceptable and effective contraceptive
 methods until 14 days after the final visit.

 4. A male participant must take effective contraception during this clinical trial or
 their heterosexual partner must take effective contraception.

 5. Positive serologic test for AChR-Ab or MUSK-Ab at the screening visit and at least 1
 of the following:

 1. History of abnormal neuromuscular transmission test demonstrated by
 sign-fiber-electromyography or repetitive nerve stimulation OR

 2. History of positive edrophonium chloride test OR

 3. Participant has demonstrated improvement in MG signs on oral cholinesterase
 inhibitors as assessed by the treating physician.

 Exclusion Criteria:

 1. Use of rituximab, belimumab, eculizumab or any monoclonal antibody/Fc-fusion biologic
 for immunomodulation within 6 months prior to screening.

 2. Immunoglobulins given by SC, IV(IVIG), or intramuscular route, or
 plasmapheresis/plasma exchange (PE) within 4 weeks before screening.

 3. Thymectomy performed < 12 months prior to screening.

 4. Total IgG level <6g/L (at screening).

 5. Participant has any laboratory abnormality (at screening) that, in the opinion of the
 investigator, is clinically significant, has not resolved at baseline, and could
 jeopardize or would compromise the participant's ability to participate in this study.

 6. Have known autoimmune disease other than MG that would interfere with the course and
 conduct of the study (such as uncontrolled thyroid disease).

 7. Have an active infection, a recent serious infection (i.e., requiring injectable
 antimicrobial therapy or hospitalization) within the 8 weeks prior to screening.

 8. History of or known infection with human immunodeficiency virus (HIV), hepatitis B
 virus (HBV), hepatitis C virus (HCV), or Mycobacterium tuberculosis. Participants must
 have negative test results for HBV surface antigen, HBV core antibody, HCV antibody,
 HIV 1 and 2 antibodies and a negative TB test at screening.