to Evaluate the Efficacy and Safety of CM336 (BCMA/CD3 Bispecific Antibody) in Adults with Moderate to Severe Autoimmune Bullous Disease

This study will set up two cohorts, Cohort 1: Patients with pemphigus, and plan to enroll approximately 20 adults with pemphigus; and Cohort 2: patients with bullous pemphigoid, and plan to enroll approximately 10 adults with bullous pemphigoid. Cohort 1 is divided into Part 1 and Part 2: Part 1 is planned to enroll approximately 10 subjects with pemphigus who had an inadequate response to prior corticosteroid therapy or whose disease uncontrolled despite high-dose corticosteroids. Part 2 is planned to enroll approximately 10 subjects with pemphigus who had an inadequate response to anti-CD20 monoclonal antibody therapy.

Inclusion Criteria:

• 1. Confirmed diagnosis of autoimmune bullous disease；
• 2. Age ≥18 years, regardless of gender；
• 3. Voluntarily signed informed consent form, with understanding of the study's nature, purpose, procedures, and willingness to comply with trial requirements.

Exclusion Criteria:

• 1. History of clinically significant diseases that, in the investigator's judgment, may pose safety risks to the subject during participation；
• 2. Prior treatment with anti-B-cell maturation antigen (BCMA) therapy；
• 3. History of allergic reactions to humanized monoclonal antibodies or known allergy to any component of CM336；
• 4. Any other condition deemed by the investigator to render the subject unsuitable for study participation.