Open-Label Extension Study to Evaluate the Safety of Efgartigimod in Adult Patients With Primary Sjögren's Syndrome (Rho plus)

Open-Label Extension Study to Evaluate the Safety of Efgartigimod in Adult Patients With Primary Sjögren's Syndrome (pSS) Who Complete Qualifying Efgartigimod pSS Studies

Efgartigimod has the potential to improve disease manifestations by the reduction of IgG autoantibodies in Sjogren's Syndrome (SjD or pSS). This open-label extension study will evaluate the long-term safety of efgartigimod in participants with SjD who have completed the treatment period of the qualifying efgartigimod study (ARGX-113-2106).

Study Overview

• Status: Completed
• Conditions: Primary Sjögren's Syndrome
• Intervention / Treatment: Biological: Efgartigimod

Detailed Description

ARGX-113-2211 is a long-term, single-arm, open-label, multicenter extension study of the pSS-qualifying efgartigimod studies designed to evaluate the long-term safety of efgartigimod in adult patients with pSS. Participants will be enrolled from both active and placebo arms of qualifying efgartigimod studies and receive efgartigimod 10 mg/kg over 48 weeks in the extension study without knowledge of their treatment assignment in the qualifying study. Eligible participants must have completed the treatment period of the qualifying study and must not have permanently discontinued the IMP in that study.

• Study Type: Interventional
• Enrollment (Actual): 24
• Phase: Phase 2

Contacts and Locations

Study Locations

• Belgium
  • Ghent, Belgium, 9000
    • Universitair Ziekenhuis Gent
• Hungary
  • Debrecen, Hungary, 4032
    • Debreceni Egyetem
  • Székesfehérvár, Hungary, 8000
    • Vita Verum Medical Egeszsegugyi Szolgaltato Bt.
• Poland
  • Grodzisk Mazowiecki, Poland, 05 825
    • MCBK SC
  • Krakow, Poland, 30 363
    • Centrum Medyczne Plejady
  • Poznan, Poland, 60-848
    • Clinical Research Center Spółka z ograniczoną odpowiedzialnością Medic-R Sp.k.
  • Skorzewo, Poland, 60 185
    • Centrum Medyczne Pratia Poznań
  • Warsaw, Poland, 02 665
    • Klinika Reuma Park Sp zoo Sp K
  • Warsaw, Poland, 00 874
    • MICS Centrum Medyczne Warszawa
  • Warsaw, Poland, 02637
    • Narodowy Instytut Geriatrii
  • Wroclaw, Poland, 50 088
    • FutureMeds sp zoo

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Is at least the legal age of consent for clinical trials when signing the ICF
• Is capable of providing signed informed consent and complying with protocol requirements
• Agrees to use contraceptive measures consistent with local regulations and the following: WOCBP must have a negative urine pregnancy test at baseline before receiving IMP
• Has completed the qualifying efgartigimod SjD studies and agrees to continue study drug treatment without interruption in the extension study

Exclusion Criteria:

• Clinically significant disease (including newly diagnosed malignancy or cardiovascular disease) or intention to have surgery during the study; or any other medical condition that, in the investigator's opinion, would confound the results of the study or put the participant at undue risk
• Pregnant or intention to become pregnant during the study
• Any severe systemic SjD manifestation that may put the participant at undue risk based on the investigator's opinion

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Efgartigimod; All participants received efgartigimod 10 mg/kg via intravenous infusion once weekly or once every 2 weeks for up to 48 weeks in this study.	Biological: Efgartigimod; Patients receiving efgartigimod infusions

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants With TEAEs, TESAEs and TEAESIs	An adverse event (AE) was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study drug, whether or not considered related to the study drug. A serious adverse event (SAE) was any untoward medical occurrence that, at any dose: resulted in death, was life threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect or any other medically important event. Treatment-emergent adverse events (TEAEs) were defined as AEs with onset on or after the first administration of study drug up to and including 60 days after the last study drug administration. Adverse events in the 'Infections and infestations' SOC were defined as AE of Special Interest (AESIs) because efgartigimod causes a transient reduction in total IgG levels.	From the first dose of study drug (Day 1) up to 60 days post last study drug, approximately 56 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of CRESS Responders at Weeks 24 and 48	A composite of relevant endpoints for Sjögren's syndrome (CRESS) measures systemic disease activity, patient-reported symptoms, tear gland function, salivary gland function, and serology, developed to assess treatment efficacy in participants with SjD. A responder is defined as improvement in at least 3 of the above mentioned 5 items of CRESS. The score ranges from 0 to 9 (higher score = worse symptoms). Responder rates for the efgartigimod-efgartigimod group in the follow-up study are supplemental to those in the antecedent study (ARGX-113-2106). Because responders from the ARGX-113-2106 study (mainly in the efgartigimod-efgartigimod group) potentially started the ARGX-113-2211 with lower baseline scores, further improvement on this efficacy measure is inherently challenging due to clinical and biological limitations.	Weeks 24 and 48
Number of Participants With Minimal Clinically Important Improvement From Baseline in ESSDAI at Weeks 24 and 48	European alliance of associations for rheumatology (EULAR) SjD activity index (ESSDAI) measures systemic disease activity in 12 domains. The activity levels of each domain are multiplied by their respective weights to obtain the total score between 0 and 123 (higher score = worse symptoms). Minimally clinically important improvement in ESSDAI was defined as improvement of at least 3 points in ESSDAI score at Weeks 24 and 48. Baseline was defined as the last available non-missing measurement from the parent study ARGX-113-2106. Responder rates for the efg-efg group in the follow-up study are supplemental to those in the ARGX-113-2106 study. Because responders from the ARGX-113-2106 study (mainly in the efg-efg group) potentially started the ARGX-113-2211 with lower baseline scores, further improvement on this efficacy measure is inherently challenging due to clinical and biological limitations.	Baseline (Day 1) and Weeks 24 and 48
Number of Participants With Low Disease Activity in ESSDAI at Weeks 24 and 48	ESSDAI measures systemic disease activity in participants with SjD and consists of 12 domains. The activity levels of each domain (range: 0-3 points) are multiplied by their respective weights (range: 1-6 points) to obtain the total score between 0 and 123 (higher score = worse symptoms). Low disease activity in ESSDAI was defined as ESSDAI score of less than 5 at Weeks 24 and 48. Responder rates for the efgartigimod-efgartigimod group in the follow-up study are supplemental to those in the antecedent study (ARGX-113-2106). Because responders from the ARGX-113-2106 study (mainly in the efgartigimod-efgartigimod group) potentially started the ARGX-113-2211 with lower baseline scores, further improvement on this efficacy measure is inherently challenging due to clinical and biological limitations.	Weeks 24 and 48
Number of Participants With Minimal Clinically Important Improvement From Baseline in clinESSDAI at Weeks 24 and 48	Clinical EULAR Sjögren's syndrome disease activity index (clinESSDAI) includes same 11 organ-specific domains as ESSDAI but with different domain weighting and this scale does not have biological domain.This way any change in clinESSDAI score reflects disease specific features irrespective of B-cell activity. clinESSDAI score ranges between 0-135 (higher score=worse symptoms).Minimal clinically important improvement in clinESSDAI was defined as improvement of at least 3 points in clinESSDAI score at Weeks 24 and 48.Baseline=last available non-missing measurement from parent study ARGX-113-2106.Responder rates for efgartigimod-efgartigimod group in follow-up study are supplemental to those in antecedent study (ARGX-113-2106).Because responders from ARGX-113-2106 study (mainly in efgartigimod-efgartigimod group) potentially started ARGX-113-2211 with lower baseline scores,further improvement on this efficacy measure is inherently challenging due to clinical and biological limitations.	Baseline (Day 1) and Weeks 24 and 48
Number of Participants With Low Disease Activity in clinESSDAI at Weeks 24 and 48	clinESSDAI includes the same 11 organ-specific domains as ESSDAI but with different domain weighting and this scale does not have the biological domain. This way any change in clinESSDAI score reflects disease specific features irrespective of B-cell activity. The clinESSDAI score ranges between 0-135 (higher score = worse symptoms). Low disease activity in clinESSDAI was defined as clinESSDAI score of less than 5 at Weeks 24 and 48. Responder rates for the efgartigimod-efgartigimod group in the follow-up study are supplemental to those in the antecedent study (ARGX-113-2106). Because responders from the ARGX-113-2106 study (mainly in the efgartigimod-efgartigimod group) potentially started the ARGX-113-2211 with lower baseline scores, further improvement on this efficacy measure is inherently challenging due to clinical and biological limitations.	Weeks 24 and 48
Number of Participants With Minimal Clinically Important Improvement From Baseline in ESSPRI at Weeks 24 and 48	EULAR Sjögren's syndrome patient-reported index (ESSPRI) is a questionnaire developed to measure self-reported symptoms in participants with SjD and consists of 3 items that measure dryness, fatigue, and pain. The total global score ranges from 0 to 10 by averaging the numeric scores for pain, fatigue, and dryness, with higher scores indicating more symptoms. Minimal clinically important improvement in ESSPRI was defined as decrease of 1 point or at least >=15% at Weeks 24 and 48. Baseline was defined as the last available non-missing measurement from the study ARGX-113-2106. Responder rates for the efg-efg group in the follow-up study are supplemental to those in the ARGX-113-2106 study. Because responders from the ARGX-113-2106 study (mainly in the efg-efg group) potentially started the ARGX-113-2211 with lower baseline scores, further improvement on this measure is inherently challenging due to biological and clinical limitations.	Baseline (Day 1) and Weeks 24 and 48
Change From Baseline in ESSDAI Score at Weeks 24 and 48	ESSDAI measures systemic disease activity in participants with SjD and consists of 12 domains: 11 organ-specific domains (cutaneous, pulmonary, renal, articular, muscular, peripheral nervous system, central nervous system, hematological, glandular, constitutional, and lymphadenopathic) and 1 biological domain reflecting B-cell activity that contributes to disease activity level scoring. The activity levels of each domain (range: 0-3 points) are multiplied by their respective weights (range: 1-6 points) to obtain the total score between 0 and 123 (higher score = worse symptoms). Baseline was defined as the last available non-missing measurement from the parent study ARGX-113-2106.	Baseline (Day 1) and Weeks 24 and 48
Change From Baseline in clinESSDAI Score at Weeks 24 and 48	clinESSDAI includes the same 11 organ-specific domains as ESSDAI but with different domain weighting and this scale does not have the biological domain. This way any change in clinESSDAI score reflects disease specific features irrespective of B-cell activity. The clinESSDAI score ranges between 0-135 (higher score = worse symptoms). Baseline was defined as the last available non-missing measurement from the parent study ARGX-113-2106.	Baseline (Day 1) and Weeks 24 and 48
Change From Baseline in ESSPRI Score at Weeks 24 and 48	ESSPRI is a questionnaire developed to measure self-reported symptoms in participants with SjD and consists of 3 items that measure dryness, fatigue, and pain. Each item includes a numeric rating scale ranging from 0: no symptoms (dryness, fatigue, or pain) to 10: maximal imaginable (dryness, fatigue, or pain). The total global score ranges from 0 to 10 and the ESSPRI is calculated by averaging the numeric scores for pain, fatigue, and dryness, with higher scores indicating more symptoms. Baseline was defined as the last available non-missing measurement from the parent study ARGX-113-2106.	Baseline (Day 1) and Weeks 24 and 48
Number of STAR Responders at Weeks 24 and 48	Sjögren's tool for assessing response (STAR) is a composite endpoint assessing multiple clinically relevant disease features. A STAR responder is defined as a participant with a score of at least 5 points. Due to the weighting, participant must be a responder on either systemic disease activity (ESSDAI), patient-reported symptoms (ESSPRI), or both to be an overall STAR responder. The score ranges between 0 and 9 (higher score = worse outcome). Responder rates for the efgartigimod-efgartigimod group in the follow-up study are supplemental to those in the antecedent study (ARGX-113-2106). Because responders from the ARGX-113-2106 study (mainly in the efgartigimod-efgartigimod group) potentially started the ARGX-113-2211 with lower baseline scores, further improvement on this efficacy measure is inherently challenging due to clinical and biological limitations.	Weeks 24 and 48
Percent Change From Baseline in Total IgG Levels in Serum at Week 48	Blood samples were collected at indicated timepoints to assess the total Immunoglobulin (Ig)G levels in serum. Total IgG concentrations were quantified using validated methods at a diagnostical laboratory. Baseline was defined as the last available non-missing measurement from the parent study ARGX-113-2106.	Baseline (Day 1) and Week 48
Percent Change From Baseline in Autoantibodies in Serum at Week 48	Blood samples were collected at indicated timepoints to assess serum autoantibodies: anti-Ro/Sjögren's syndrome-related antigen A (SS-A) and anti-La/Sjögren's syndrome-related antigen B (SS-B). Baseline was defined as the last available non-missing measurement from the parent study ARGX-113-2106.	Baseline (Day 1) and Week 48
Serum Concentrations of Efgartigimod	Serum samples were collected at indicated timepoints to assess the pharmacokinetic (PK) profile of efgartigimod.	Pre-dose and post-dose at Baseline (Day 1) and pre-dose at Weeks 24 and 48
Number of Participants With ADA Against Efgartigimod Over the 48-week Treatment Period	Blood samples were collected to assess anti-drug antibodies (ADAs) against efgartigimod. Samples were analyzed by the designated laboratory in a 3-tiered approach using validated immunogenicity assays. ADA incidence included total number of participants with treatment-boosted and treatment-induced ADA. Treatment-boosted ADA was defined as participants who had a baseline positive sample and the titer value increased 4-fold or more compared to baseline. Treatment-induced ADA was defined as participants who had a baseline negative sample and at least 1 positive post-baseline samples. Number of participants with ADA incidence is presented here.	From Baseline (Day 1) up to 48 weeks

Collaborators and Investigators

• Sponsor: argenx
• Collaborators: IQVIA Pty Ltd

Study record dates

Study Major Dates

• Study Start (Actual): November 29, 2023
• Primary Completion (Actual): February 3, 2025
• Study Completion (Actual): February 3, 2025

Study Registration Dates

• First Submitted: November 16, 2023
• First Submitted That Met QC Criteria: January 2, 2024
• First Posted (Actual): January 12, 2024

Study Record Updates

• Last Update Posted (Actual): February 20, 2026
• Last Update Submitted That Met QC Criteria: February 3, 2026
• Last Verified: April 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Mouth Diseases; Stomatognathic Diseases; Pathologic Processes; Arthritis; Joint Diseases; Rheumatic Diseases; Connective Tissue Diseases; Autoimmune Diseases; Immune System Diseases; Disease; Eye Diseases; Arthritis, Rheumatoid; Xerostomia; Salivary Gland Diseases; Dry Eye Syndromes; Lacrimal Apparatus Diseases; Syndrome; Sjogren's Syndrome; efgartigimod alfa
• Other Study ID Numbers: ARGX-113-2211

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No