SC291-102 is a Phase 1 study to evaluate SC291 safety and tolerability, preliminary clinical response, cellular kinetics and exploratory assessments for subjects with severe autoimmune diseases.

Systemic lupus erythematosus (SLE) is an autoimmune disease with multisystemic organ involvement that is often fatal. SLE is subcategorized as extrarenal lupus (ERL) or lupus nephritis (LN). B cell depletion therapies have played an important role in the treatment of multiple B cell-driven autoimmune diseases.

Subjects included in this trial will be subjects with diagnoses of systemic lupus erythematosus (SLE) including lupus nephritis (LN) and extrarenal systemic lupus erythematosus (ERL), or anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) (including Granulomatous Polyangitis and Microscopic Polyangiitis) who have refractory disease, have relapsed and have not shown appropriate clinical responses following prior systemic treatments.

This study is being conducted to evaluate the safety and efficacy of an investigational cell therapy, SC291, that can be given to patients with LN, ERL or AAV, in separate parallel cohorts, who have active disease.

A single dose of SC291 will be evaluated in patients who are pretreated with a standard regimen including cyclophosphamide (CY) and fludarabine (FLU).

Inclusion Criteria:

1. Age ≥18 and ≤75

2. For LN cohort:

   • Diagnosis of SLE based on the 2019 European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR)
   • Biopsy-proven LN class III or IV, according to 2018 Revised International Society of Nephrology/Renal Pathology Society (ISN/RPS) criteria
   • Refractory disease to ≥ 2 prior treatment regimens

3. For ERL cohort:

   • Diagnosis of SLE based on the 2019 European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) classification criteria for adult SLE
   • Severe or relapsing disease not responding to at least 2 prior recent disease-modifying therapies

4. For AAV Cohort, diagnosed with Granulomatous Polyangiitis (GPA) or Microscopic Polyangiitis (MPA) based on the 2022 ACR/EULAR classification criteria

Exclusion Criteria:

1. Prior CD19-directed cell therapy including CAR T treatment or other genetically modified cell therapy (e.g., Natural Killer (NK) cell)
2. For LN and ERL Cohorts, central nervous system (CNS) lupus manifestations or history or presence of CNS disorder
3. For LN and ERL Cohorts, diagnosis of anti-phospholipid antibody syndrome
4. For AAV Cohort only, Diagnosis of Eosinophilic Granulomatosis with Polyangiitis (EGPA) as defined by the 2022 ACR/EULAR classification criteria for EGPA -