CRR at Week 76, defined as (both must be met): * Urine protein to creatinine ratio (UPCR) ≤ 0.5 mg/mg AND * No decrease from baseline of ≥ 20% in estimated glomerular filtration rate (eGFR)

Occurrence of treatment-emergent adverse events up to the final study visit (maximum 3 years of study treatment plus 6-month safety follow-up period).

Occurrence of serious adverse events up to the final study visit (maximum 3 years of study treatment plus 6-month safety follow-up period).

Occurrence of adverse events of special interest up to the final study visit (maximum 3 years of study treatment plus 6-month safety follow-up period). Adverse events of special interest include the anticipated risks of treatment with cenerimod, known class effects, and events that may be related to systemic lupus erythematosus comorbidities, i.e., adverse events related to: * Effects on heart rate and rhythm * Hypotension * Hypertension * Cardiovascular * Hepatobiliary disorders / liver enzyme abnormalities * Pulmonary * Eye disorders * Infections * Skin malignancies * Non-skin malignancies

Response on SRI-4 is defined as: * Reduction from baseline of at least 4 points in the modified Systemic Lupus Erythematosus Disease Activity Index-2000 score (mSLEDAI-2K \[SLEDAI-2K modified to exclude leukopenia, thus mSLEDAI-2K\]), and * No new British Isles Lupus Assessment Group-2004 (BILAG) A organ domain score and not more than one new BILAG B organ domain score compared to baseline, and * No worsening from baseline in subjects' lupus disease activity, where worsening is defined as an increase ≥ 0.30 points on a 3-point Physician's Global Assessment visual analog scale (PGA VAS), and * No violation of specified medication rules detailed in the core protocol.

Treatment-emergent AEs are defined as any adverse event that occurs after the first dose of study treatment and up to 180 days after the last dose. This includes serious AEs (SAEs), AEs of special interest (AESIs), and AEs leading to permanent discontinuation of study treatment. AEs are coded using MedDRA and assessed by the investigator.

Number of participants who permanently discontinue study treatment due to adverse events.

Change in systolic blood pressure (SBP), diastolic blood pressure (DBP), and body weight from baseline to each post-baseline assessment. Measurements are performed in duplicate under standardized conditions.

Change in heart rate (HR), PR interval, QRS interval, QTcB interval, and QTcF interval from baseline to each post-baseline assessment.ECG abnormalities are assessed based on pre-defined criteria.

Change in hematology, blood chemistry, and urinalysis variables from baseline to each post-baseline assessment. Marked laboratory abnormalities are defined based on central laboratory reference ranges.

Plasma concentrations of cenerimod are measured at multiple time points to characterize the pharmacokinetic profile. Concentrations are determined using a validated bioanalytical method (e.g., LC-MS/MS).

Cmax is derived from plasma concentration-time profiles using non-compartmental analysis. Assessed during the first dosing interval on Day 1 and at steady state (Month 2).

tmax is derived from plasma concentration-time profiles using non-compartmental analysis. Assessed during the first dosing interval on Day 1 and at steady state (Month 2). Time Frame: Day 1 and Month 2

AUC0-24 is derived during the first dosing interval on Day 1 using non-compartmental analysis.

AUCτ is derived at steady state (Month 2) using non-compartmental analysis.

AI is calculated as the ratio of AUC at steady state (Month 2) to AUC after the first dose (Day 1).

Change in total blood lymphocyte count from baseline to each post-baseline assessment. This is a key pharmacodynamic marker for cenerimod.

Treatment-emergent medically relevant ECG abnormalities are defined as new or worsening abnormalities from baseline to each post-baseline assessment, as determined by central reading.

Treatment-emergent marked laboratory abnormalities are defined as new or worsening abnormalities in hematology, blood chemistry, or urinalysis from baseline to each post-baseline assessment, based on central laboratory criteria.

The primary endpoint is the absolute change from baseline in the modified Systemic Lupus Erythematosus Activity Index 2000 (mSLEDAI-2K) score. The SLEDAI-2K is a cumulative index of lupus disease activity scored by the physician. It is calculated from 24 individual descriptors across 9 organ systems, with weighted scores of 2-8, and measures disease activity within the last 10 days. 0 points indicates inactive disease, and 105 points is the maximum possible score. In this study the SLEDAI-2K was modified, to exclude leucopenia (minus 1 point), due to the mechanism of action of cenerimod. Improvement in systemic lupus erythematosus disease activity is defined as a reduction in SLEDAI-2K score of greater than or equal to 4. A decreased score, i.e., a negative change, indicates an improvement in systemic lupus erythematosus disease activity from baseline to Month 6.

Absolute bioavailability of a single oral dose of 4 mg cenerimod, calculated as: area under the plasma concentration-time curve from zero to infinity (AUC0-∞) of the oral dose / AUC0-∞ of the intravenous dose, normalized by dose.

The plasma PK parameter of cenerimod will be derived by non-compartmental analysis of plasma concentration-time profiles.

The primary objective of the clinical study was to asses whether cenerimod could reduce the number of circulating lymphocytes in the bloodstream of people with systemic lupus erythematosus (SLE). The change was defined as: Total lymphocyte count at end-of-treatment (EOT) minus total lymphocyte count at baseline. A negative change over time indicates that the number of peripheral circulating lymphocytes has decreased. The reduction of the total lymphocyte count over a treatment period indicates a pharmacodynamic effect. The value at baseline was defined as the last non-missing value obtained from a sample taken prior to the first study treatment intake. End-of-treatment (EOT) was defined as the last post-baseline value with treatment for at least 21 days up to Week 12.

The primary objective of the clinical study was to assess whether cenerimod could reduce the number of circulating lymphocytes in the bloodstream of people with systemic lupus erythematosus (SLE). The change was defined as: Total lymphocyte count at visit minus total lymphocyte count at baseline. A negative change over time indicates that the number of peripheral circulating lymphocytes has decreased. The reduction of the total lymphocyte count over a treatment period indicates a pharmacodynamic effect. The value at baseline was defined as the last non-missing value obtained from a sample taken prior to the first study treatment intake. End-of-treatment (EOT) was defined as the last post-baseline value with treatment for at least 21 days up to Week 12.