This study will evaluate the safety and tolerability of iscalimab at two dose levels in patients with Sjögren's Syndrome, who participated in the TWINSS core study, CCFZ533B2201 (NCT03905525). Additionally, this Extension study will further explore the pharmacokinetics (PK) and efficacy of iscalimab at two dose level.

This study was a continuation of the TWINSS core study CCFZ533B2201 (NCT03905525) that offered continuation of treatment for participants who completed the core study and were deemed by the Investigator to clinically benefit from continued iscalimab therapy based upon response to therapy at the end of the treatment period of the core study. The extension study was a 48-week treatment study, with a safety follow-up period of 12 weeks, to provide additional safety and tolerability information for iscalimab.At Week 60 of the TWINSS core study, eligible participants had the option to enroll in the extension study.

Participants were classified as treatment responders or non-responder based on their European League Against Rheumatism (EULAR) Sjögren's syndrome disease activity index (ESSDAI) and EULAR Sjögren's syndrome patient reported index (ESSPRI) scores from predefined time points in the core study. In the extension study, participants were reassigned to either iscalimab 600 mg or 300 mg subcutaneously via prefilled syringes (PFS) based on their responder status and the iscalimab doses that they received in the core study

All participants enrolled in the extension study received a weekly loading regimen at the start of the treatment period for the initial 3 weeks, followed by a subcutaneous maintenance regimen (600 or 300 mg subcutaneously every 2 weeks). Injections were performed at site or at home by site staff or participant/caregiver.

Study blinding for the extension study was maintained until final database lock of the core study, upon which the participants and Investigators were unblinded, making it an open-label study through Week 120 (end of study visit).

Inclusion Criteria:

1. Participants had to have participated in the TWINSS core study, CCFZ533B2201 (NCT03905525), and had to have completed the entire treatment period up to Week 48 and the follow-up period up to Week 60.
2. Signed informed consent had to be obtained prior to participation in the Extension study (i.e., before commencement of the Week 60 assessments of the core study).
3. In the judgment of the Investigator, participants had to be expected to clinically benefit from continued iscalimab therapy.

Exclusion Criteria:

1. Sjögren's Syndrome overlap syndromes where another autoimmune rheumatic disease constituted the principle illness, specifically:

   • Moderate-to-severe active systemic lupus erythematosus (SLE) with anti-dsDNA positivity and renal involvement, or other organ involvement that impeded on the ability to score ESSDAI domains
   • Active rheumatoid arthritis (RA) that impeded on the ability to score the ESSDAI articular domain
   • Systemic sclerosis
   • Any other concurrent connective tissue disease (e.g., lupus nephritis (LN), large vessel vasculitis (LVV), Sharp syndrome (mixed connective tissue disease) that was active and required immunosuppressive treatment outside the scope of this trial and would impede on Sjögren's Syndrome organ domain assessments

2. Use of other investigational drugs other than iscalimab during the core study

3. Active uncontrolled viral, bacterial or other infections requiring systemic treatment at the time of enrollment, or history of recurrent clinically significant infection or of bacterial infections with encapsulated organisms

4. Pregnant or nursing (lactating) women, where pregnancy was defined as the state of a female after conception and until the termination of gestation, confirmed by a positive human Chorionic Gonadotropin (hCG) laboratory test

5. Women of child-bearing potential (WOCBP), defined as all women physiologically capable of becoming pregnant, unless they were using highly effective methods of contraception during dosing and for 14 weeks after stopping the investigational drug.

6. Missing ESSDAI (Cohort 1 and Cohort 2) or ESSPRI (Cohort 2) scores in the core study at Weeks 0 and 4 or Weeks 40 and 48.

Novartis is committed to sharing access to patient-level data and supporting clinical documents from eligible studies with qualified external researchers. Requests are reviewed and approved by an independent review panel on the basis of scientific merit. All data provided is anonymized to protect 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

The study was conducted as a double-blind treatment until the final database lock of the Core study (NCT03905525). During this period, participants, Investigator, site staff, and persons performing the assessments remained blinded to the identity of the treatment until the final database lock of Core study (NCT03905525)