CM336 for Active Sjogren's Syndrome Study

Prior treatment

• Active infection requiring intravenous anti-infective treatment within 3 months before first dose of study drug, or oral anti-infective treatment within 2 weeks before first dose of study drug.
• History of disseminated herpes zoster, or ocular/Central Nervous System herpes zoster, or systemic herpes simplex or symptomatic herpes zoster infection within 3 months before first dose of study drug.
• Deep vein thrombosis or pulmonary embolism within 6 months before first dose of study drug.
• Major surgery within 3 months before screening or planned during the study period (requiring hospitalization and general anesthesia, excluding diagnostic procedures).
• Prior treatment with any anti-B-cell maturation antigen targeted therapy (including cell therapy or antibody therapy, etc.).
• Receipt of prohibited medications within the corresponding timeframes.

Other illness

• Presence of other systemic autoimmune diseases besides primary Sjögren's disease.
• Presence of other autoimmune or inflammatory diseases.
• Presence of any other medical condition with clinical manifestations overlapping with primary Sjögren's disease or that may interfere with result interpretation.
• History of severe allergic reactions (as judged by the investigator), or history of hypersensitivity to monoclonal antibodies or any component of CM336.
• Presence of congenital immunodeficiency, or acquired immunodeficiency not related to the participant's autoimmune disease or its medical treatment.
• Positive HIV antibody, positive Treponema pallidum antibody, or history of hepatitis B virus (HBV) or hepatitis C virus (HCV) infection.
• History of tuberculosis infection.
• History of pulmonary arterial hypertension with WHO functional class II or above.
• Presence of uncontrolled asthma or chronic obstructive pulmonary disease (COPD); uncontrolled diabetes mellitus; uncontrolled thyroid or other endocrine disorders; uncontrolled psychiatric disorders.
• History of malignancy within 5 years before first dose of study drug (except cured basal cell carcinoma, squamous cell carcinoma of the skin, and cervical carcinoma in situ without evidence of recurrence).

Lab values

• History of severe cardiovascular or cerebrovascular disease, including but not limited to:
  • Unstable arrhythmia, unstable angina pectoris.
  • New York Heart Association (NYHA) functional class III or IV.
  • Uncontrolled hypertension (average systolic blood pressure ≥160 mmHg or diastolic blood pressure ≥100 mmHg on two measurements despite optimal treatment).
  • Fridericia-corrected QT interval(QTcF) \>450 ms for males or \>470 ms for females
• Presence of any of the following during screening:
  • Neutrophil count \<1×10⁹/L, platelet count \<100×10⁹/L, or hemoglobin \<80 g/L (applicable only to patients without hematologic involvement).
  • Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) \>2× upper limit of normal (ULN).
  • estimated Glomerular Filtration Rate(eGFR) \<40 mL/min/1.73m² (2021 Chronic Kidney Disease Epidemiology Collaboration formula).
  • Prothrombin time (PT) or activated partial thromboplastin time (APTT) \>1.5×Upper Limit of Normal.

Other

• Presence of active, life-threatening, or organ-threatening SjD complications at screening.

• Male or female, aged 18 to 75 years (inclusive) at the time of signing the informed consent form (ICF), and willing to comply with the study protocol requirements.
• Body weight ≥ 45 kg at screening.
• Voluntary compliance with the protocol requirements for permitted/prohibited concomitant therapies.
• Definitive diagnosis of primary Sjögren's disease (SjD) according to the 2016 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) classification criteria, and meeting all of the following requirements:
  • Seropositive for at least one SjD-related autoantibody.
  • Prior treatment with at least two systemic therapies for SjD symptoms.
  • Active disease at screening, defined as Clinical EULAR Sjögren's Syndrome Disease Activity Index(ClinESSDAI) ≥ 5.
• No better therapeutic alternative available for the study participant.