Background/Purpose: Sjögren’s syndrome is a heterogeneous autoimmune disease with no approved disease-modifying treatments. The aim of this systematic review was to evaluate primary Sjögren’s syndrome (pSS) patient characteristics included in clinical trials (CTs).

Methods: This systematic review was undertaken according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. The search was performed using PubMed, EMBASE, OVID, and ClinicalTrials.gov for phase II and III clinical trials of biologic drugs in pSS including ≥30 adult patients and published between 2010 and 2024. Baseline characteristics of participants and trial-related information were collected. Descriptive statistics were used for analysis.

Results: A total of 16 publications were eligible to be included in this review, with 87.5% being published after 2017. The CTs were predominantly randomized controlled trials with a placebo arm (93.8%) and phase II trials (62.5%). The mean follow-up period was 32 weeks. The majority of the CTs (56.3%) were fully sponsored by industry sources. A summary of the main characteristics of CTs selected is shown in Table 1.Inclusion criteria often focused on high disease activity, as measured by the ESSDAI score, with 62.5% requiring an ESSDAI score ≥5. Salivary flow measures were also common, used in 43.8% of the CTs. The primary outcomes were diverse, but 56.3% of the CTs focused on reducing ESSDAI scores.The CTs included in the analysis reported a total of 1607 patients, predominantly female (94%), with a mean age of 51.0 (4.04) years. The mean time from diagnosis was 6.47 (2.48) years. Racial diversity was underreported, with only 37.5% of CTs providing data on race. Among those, 77.8% of participants were White, 11.9% were Asian, and 5.2% were Black.Disease characteristics included high anti-SSA/Ro antibody positivity (92.9%), while other immunological and serological features are shown in Table 2. Mean ESSDAI score was 9.6 (2.8) and mean ESSPRI score was 6.3 (0.88). Other measurements of subjective symptoms notably a numerical rating scale (NRS) were also assed, including an NRS for dryness, fatigue and pain mean values of 7.2/10, 6.7/10 and 5.7/10, respectively. Patient-reported measures of disease burden are shown in Table 3.Concomitant treatments were common, with 87.5% of the CTs allowing simultaneous therapies. Despite most of the CTs being multicentric (75%), global representation was limited: only five CTs recruited patients in more than two continents and no CTs recruited in Africa.

Conclusion: This review highlights key challenges in pSS CTs: notably limited patient diversity, high subjective symptom burden, and heterogeneous outcomes measures. While the use of ESSDAI/ESSPRI is rising and reporting of race and ethnicity is improving, standardization remains incomplete. Earlier intervention and broader recruitment are needed to advance pSS therapies.

Table 1: Selected trials for biologics in pSS

RCT: randomized clinical trial

Table 2 : Serological features of patients included in the CTs

Data are mean (SD), median (min, max), or percentages.

ANA=antinuclear antibodies; anti-La/SSB= antibodies against Sjögren’s Syndrome B; RF=Rheumatoid Factor; IgG=Immunoglobulin G

Table 3: Patient-reported measures of disease burden

Data are mean (SD), median (min, max), or percentages.

SF-36: Short Form-36; PCS: Physical Component Summary of SF-36; MCS: Mental Component Summary of SF-36; MFI-20: Multidimensional Fatigue Inventory-20.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/comparative-analysis-of-patients-included-in-trials-utilizing-biologic-drugs-in-the-treatment-of-primary-sjogrens-syndrome/