A Study of KITE-363 in Participants With Refractory Autoimmune Diseases

Inclusion Criteria

• Key Inclusion Criteria: Inclusion Criteria for systemic lupus erythematosus (SLE) and lupus nephritis (LN): - Age ≥ 18 and ≤ 75 years - Meet the European Alliance of Associations for Rheumatology (EULAR)- American College of Rheumatology (ACR) 2019 classification criteria for SLE - Presence of either double-stranded deoxyribonucleic acid (DNA) anti- double-stranded DNA (anti-dsDNA) and/or anti-Smith antibodies at screening per local laboratory. - Moderate to severe, active disease defined as at least one British Isles Lupus Assessment Group (BILAG-A) score or 2 BILAG B (excluding constitutional and/or neuropsychiatric organ system). - Refractory to steroids and inadequate response or intolerance to at least 2 of the following treatments, used for at least 3 months each: cyclophosphamide, mycophenolate mofetil or its derivatives, belimumab, anifrolumab, rituximab, obinutuzumab, methotrexate, azathioprine, cyclosporin, tacrolimus, or voclosporin. - For LN: Refractory to steroids and inadequate response or intolerance to at least 2 of the following treatments, used for at least 3 months each: cyclophosphamide, mycophenolate mofetil or its derivatives, belimumab, rituximab, obinutuzumab, azathioprine, cyclosporin, tacrolimus, or voclosporin Inclusion Criteria for LN: - Renal biopsy-proven Class III or intravenous (IV) ± V LN according to the revised International Society of Nephrology and Renal Pathology Society (ISN/RPS) criteria within 6 months prior to or during screening - Evidence of active LN at screening Inclusion Criteria for systemic sclerosis (SSc): - Age ≥ 18 and ≤ 60 years - Early systemic sclerosis according to ACR/EULAR 2013 classification criteria with active skin disease and/or progressive ILD - Refractory or intolerance to 1 of the following for a minimum of 3 months and/or contraindication: mycophenolate mofetil or its derivatives, methotrexate, tocilizumab (or other IL-6 inhibitor), rituximab (or other B-cell depleting agent), nintedanib (or other antifibrotic agents), cyclophosphamide. - High-resolution computer tomography (HRCT) scan and pulmonary function test (PFT) within 3 months prior to screening to evaluate for presence of SSc-ILD. Inclusion Criteria for idiopathic inflammatory myopathy (IIM): - Age ≥ 18 years - IIM based on EULAR/ACR 2017 classification (excluding inclusion body myositis). - Active disease demonstrated by electromyography (EMG). Magnetic resonance imaging (MRI) or muscle enzyme - Moderate to severe disease activity - Positive for myositis specific antibodies for patients with non-dermatomyostitis IIM - HRCT scan and PFT within 3 months prior to screening to evaluate for presence of IIM-ILD. - Refractory or intolerance to at least 1 month of glucocorticoids and standardized use of at least 2 immunosuppressant/modulator (eg, intravenous gamma globulins, methotrexate, mycophenolate mofetil and its derivatives, azathioprine, cyclophosphamide, calcineurin inhibitors, Janus kinase (JAK) inhibitors, rituximab or other B-cell depleting agent). Inclusion Criteria for all Cohorts: - Adequate hepatic, renal, pulmonary, and cardiac function. Key Exclusion Criteria: Exclusion Criteria for all Cohorts: - Females of childbearing potential who are pregnant or breast feeding. - Dialysis within the past year. - History of malignancy, within the last 5 years. - Hypogammaglobulinemia requiring immunoglobulin replacement. - History of autologous or allogeneic stem cell transplant and/or organ transplant. - Prior treatment with cellular therapy, gene therapy and/or T-cell engager therapy. - Known history of HIV infection, or hepatitis B or C virus infections. - Active or untreated latent tuberculosis (TB). - Active or uncontrolled infections. - Nonspecific, overlap, mixed autoimmune diseases not clearly identified into any of the studied cohorts. Exclusion Criteria for LN: - Significant pre-existing damage or rapidly progressive glomerulonephritis (GN). Exclusion Criteria for SLE: - Drug-induced SLE. - Catastrophic antiphospholipid syndrome. - Thrombotic thrombocytopenic purpura. - Active or unstable lupus neuropsychiatric manifestations within last 6 months. Exclusion Criteria for SSc: - Digital ulceration or necrosis with infection. - Severe pulmonary hypertension. - History of systemic sclerosis renal crisis within 12 months prior to enrollment. - History of active bleeding related to gastric antral vascular ectasia. Exclusion Criteria for IIM: - Other inflammatory and noninflammatory myopathies. - Severe, irreversible muscle damage. Note: Other protocol defined Inclusion/Exclusion criteria may apply.