The purpose of this study is to evaluate the efficacy and safety of rapcabtagene autoleucel (administered once following lymphodepletion) in patients with active, refractory systemic lupus erythematosus (SLE) or active, refractory lupus nephritis (LN).

Key Inclusion Criteria:

• Men and women with SLE, aged >= 18 years and =< 75 years at screening, fulfilling the 2019 European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) classification criteria for SLE at screening.
• Participant must be positive for at least one of the following autoantibodies at screening: antinuclear antibodies (ANA) at a titer of >= 1:80 (on HEp-2 cells or an equivalent positive test), or anti-dsDNA (above the ULN); or anti-Sm (above the ULN) as determined by a central laboratory.
• Active lupus nephritis without signs of significant chronicity or active systemic lupus erythematosus
• SLEDAI-2K Criteria at screening: SLEDAI-2K score >= 6 points (Gladman et al 2002, Touma et al 2011), excluding points attributed to "fever", "lupus headache", "alopecia", and "organic brain syndrome".
• Inadequate response at screening to at least two therapies

Key Exclusion Criteria:

• Any acute, severe lupus related-flare at screening that needs immediate treatment other than pulse GCs and/or makes the immunosuppressive washout impossible and, thus, makes the participant ineligible for CD19 CAR-T therapy
• Inadequate organ function during screening and prior to randomization
• History or current diagnosis of ECG or cardiac abnormalities indicating significant risk of safety for participants prior to randomization
• Human immunodeficiency virus (HIV) positivity at screening.
• Acute or chronic infection with hepatitis B (HBV) or hepatitis C (HCV) at screening.
• Grade 2 or higher thromboembolic event in the past 4 weeks prior to screening.

Other protocol-defined inclusion/exclusion criteria may apply.

Novartis is committed to sharing with qualified external researchers, access to patient-level data and supporting clinical documents from eligible studies. These requests are reviewed and approved by an independent review panel on the basis of scientific merit. All data provided is anonymized to respect the privacy of patients who have participated in the trial in line with applicable laws and regulations. This trial data availability is according to the criteria and process described on www.clinicalstudydatarequest.com.