Faculty Bibliography

OBJECTIVES/OBJECTIVE:To identify phenotype clusters and their trajectories in psoriatic arthritis (PsA) and examine the association of the clusters with treatment response in a real-world setting. METHODS:In the multicentre PsA Research Consortium (PARC) study, we applied factor analysis of mixed data to reduce dimensionality and collinearity, followed by hierarchical clustering on principal components. We then evaluated the transition of PsA clusters and their response to new immunomodulatory therapy and tumour necrosis factor inhibitor (TNFi). RESULTS:Among 627 patients with PsA, three clusters were identified: mild PsA and psoriasis only (PsO) (Cluster 1, 47.4%), severe PsA and mild PsO (Cluster 2, 34.3%) and severe PsA and severe PsO (Cluster 3, 18.3%). Among 339 patients starting or changing, significant differences in response were observed (mean follow-up of 0.7 years, SD 0.8), with Cluster 3 showing the largest improvements in cDAPSA and PsAID. No differences were found among those starting TNFi (n=218). cDAPSA remission and PsAID patient acceptable symptom state were achieved in 10% and 54%, respectively. Clusters remained stable over time despite treatment changes, though some transitions occurred, notably from Cluster 3 to milder clusters. CONCLUSION/CONCLUSIONS:Data-driven clusters with distinct therapy responses identified in this real-world study highlight the extensive heterogeneity in PsA and the central role of psoriasis and musculoskeletal severity in treatment outcomes. Concurrently, these findings underscore the need for better outcome measures, particularly for individuals with lower disease activity.

OBJECTIVES/OBJECTIVE:To identify phenotype clusters and their trajectories in psoriatic arthritis (PsA) and examine the association of the clusters with treatment response in a real-world setting. METHODS:In the multicentre PsA Research Consortium (PARC) study, we applied factor analysis of mixed data to reduce dimensionality and collinearity, followed by hierarchical clustering on principal components. We then evaluated the transition of PsA clusters and their response to new immunomodulatory therapy and tumour necrosis factor inhibitor (TNFi). RESULTS:Among 627 patients with PsA, three clusters were identified: mild PsA and psoriasis only (PsO) (Cluster 1, 47.4%), severe PsA and mild PsO (Cluster 2, 34.3%) and severe PsA and severe PsO (Cluster 3, 18.3%). Among 339 patients starting or changing, significant differences in response were observed (mean follow-up of 0.7 years, SD 0.8), with Cluster 3 showing the largest improvements in cDAPSA and PsAID. No differences were found among those starting TNFi (n=218). cDAPSA remission and PsAID patient acceptable symptom state were achieved in 10% and 54%, respectively. Clusters remained stable over time despite treatment changes, though some transitions occurred, notably from Cluster 3 to milder clusters. CONCLUSION/CONCLUSIONS:Data-driven clusters with distinct therapy responses identified in this real-world study highlight the extensive heterogeneity in PsA and the central role of psoriasis and musculoskeletal severity in treatment outcomes. Concurrently, these findings underscore the need for better outcome measures, particularly for individuals with lower disease activity.

Psoriasis is a chronic inflammatory skin disease that often precedes the development of psoriatic arthritis. Advances over the past 10 years have deepened our understanding of the transition from skin inflammation to joint inflammation, revealing various phases during which genetic, environmental, and immunological factors can affect this transition. In 2023, a European Alliance of Associations for Rheumatology task force outlined key considerations for identifying individuals with subclinical disease from those with clinically stabilised disease. Discerning between subclinical psoriatic arthritis and very early disease is crucial and raises doubts and questions about when an individual transitions from being at risk to having established psoriatic arthritis. Labelling this stage as very early psoriatic arthritis rather than subclinical disease might have substantial clinical and therapeutic implications. This Viewpoint highlights the importance of precisely identifying the different stages of progression of psoriatic arthritis for timely interventions and better outcomes for patients.

The increasing prevalence of autoimmune and immune-mediated diseases (AIMDs) underscores the need to understand environmental factors that contribute to their pathogenesis, with the microbiome emerging as a key player. Despite significant advancements in understanding how the microbiome influences physiological and inflammatory responses, translating these findings into clinical practice remains challenging. This viewpoint reviews the progress and obstacles in microbiome research related to AIMDs, examining molecular techniques that enhance our understanding of microbial contributions to disease. We discuss significant discoveries linking specific taxa and metabolites to diseases such as rheumatoid arthritis, systemic lupus erythematosus and spondyloarthritis, highlighting the role of gut dysbiosis and host-microbiome interactions. Furthermore, we explore the potential of microbiome-based therapeutics, including faecal microbiota transplantation and pharmacomicrobiomics, while addressing the challenges of identifying robust microbial targets. We advocate for integrative, transdisease studies and emphasise the need for diverse cohort research to generalise findings across populations. Understanding the microbiome's role in AIMDs will pave the way for personalised medicine and innovative therapeutic strategies.

OBJECTIVE:Psoricatic disease remains underdiagnosed and undertreated. We developed and validated a suite of novel, smartphone sensor-based assessments that can be self-administered to measure cutaneous and musculoskeletal signs and symptoms of psoriatic disease. METHODS:Participants with psoriasis, psoriatic arthritis, or healthy controls were recruited between June 5, 2019, and November 10, 2021, at two academic medical centers. Concordance and accuracy of digital measures and image-based machine learning models were compared to their analogous clinical measures from trained rheumatologists and dermatologists. RESULTS:assessment categorized physician-assessed upper extremity involvement, considering joint tenderness or enthesitis (AUROC = 0.68 (0.47-0.85)). CONCLUSION/CONCLUSIONS:The Psorcast digital assessments achieved significant clinical validity, although they require further validation in larger cohorts before use in evidence-based medicine or clinical trial settings. The smartphone software and analysis pipelines from the Psorcast suite are open source and freely available.

Inflammatory epithelial diseases are spurred by the concomitant dysregulation of immune and epithelial cells. How these two dysregulated cellular compartments simultaneously sustain their heightened metabolic demands is unclear. Single-cell and spatial transcriptomics (ST), along with immunofluorescence, revealed that hypoxia-inducible factor 1α (HIF1α), downstream of IL-17 signaling, drove psoriatic epithelial remodeling. Blocking HIF1α in human psoriatic lesions ex vivo impaired glycolysis and phenocopied anti-IL-17 therapy. In a murine model of skin inflammation, epidermal-specific loss of HIF1α or its target gene, glucose transporter 1, ameliorated epidermal, immune, vascular, and neuronal pathology. Mechanistically, glycolysis autonomously fueled epithelial pathology and enhanced lactate production, which augmented the γδ T17 cell response. RORγt-driven genetic deletion or pharmacological inhibition of either lactate-producing enzymes or lactate transporters attenuated epithelial pathology and IL-17A expression in vivo. Our findings identify a metabolic hierarchy between epithelial and immune compartments and the consequent coordination of metabolic processes that sustain inflammatory disease.

Psoriatic arthritis (PsA) is a systemic chronic inflammatory disease that develops in up to 30% of patients with psoriasis. Mixed data variably support the potential ability to "prevent" and/or delay PsA through use of systemic therapies in psoriasis patients. Though intriguing, almost all of these studies are retrospective in nature, and hold substantial limitations and potential biases that challenge the ability to meaningfully interpretation their results. Thus, the authors believe prospective observational and interventional studies are crucial to understanding our ability to truly modify the transition from psoriasis to psoriatic arthritis and delay or prevent PsA onset.

BACKGROUND:Tumor necrosis factor inhibitors (TNFi) are frequently chosen as the first biologic for patients with psoriatic arthritis (PsA). Given that many patients with PsA are TNFi inadequate responders (TNF-IR; either inadequate efficacy or intolerance), treatments utilizing alternative mechanisms of action are needed. In phase 3 studies, the fully human interleukin (IL)-23p19 subunit-inhibitor, guselkumab, was efficacious in patients with active PsA, including TNFi-IR. Efficacy was generally consistent between TNFi-naïve and TNFi-experienced cohorts; however, in the latter, higher response rates have been observed with the Q4W dosing regimen relative to the Q8W dosing regimen for some endpoints, suggesting the need to evaluate whether more frequent dosing may provide an incremental clinical benefit for TNFi-IR patients. METHODS:The phase 3b SOLSTICE study will assess guselkumab efficacy and safety in TNFi-IR PsA patients. Eligibility criteria include a PsA diagnosis for ≥ 6 months; active disease (≥ 3 swollen, ≥ 3 tender joints, C-reactive protein ≥ 0.3 mg/dL); and inadequate efficacy with, and/or intolerance to, one prior TNFi. Participants will be randomized 1:1:1 to guselkumab Q4W or Q8W or placebo→guselkumab Q4W (at Week 24). The primary endpoint is the proportion of patients achieving ≥ 20% improvement in the American College of Rheumatology criteria (ACR20) at Week 24. Major secondary endpoints include ACR50, ACR70; an Investigator's Global Assessment (IGA) of psoriasis score of 0/1 plus ≥ 2-grade reduction and ≥ 90% improvement in Psoriasis Area and Severity Index (both among patients with ≥ 3% body surface area affected by psoriasis and baseline IGA ≥ 2); minimal/very low disease activity; and changes from baseline in Health Assessment Questionnaire-Disability Index, the 36-item Short-Form Health Survey Physical Component Summary, and Functional Assessment of Chronic Illness Therapy-Fatigue scores. The target sample size (N = 450) is estimated to provide > 90% power in detecting differences between each guselkumab group and the placebo group for the primary endpoint assuming a 2-sided α = 0.05. Cochran-Mantel-Haenszel testing and analyses of covariance will be used to compare efficacy for binary and continuous endpoints, respectively. DISCUSSION/CONCLUSIONS:Findings from the phase 3b SOLSTICE study, the design of which was informed by results from previously conducted phase 3 studies, is expected to provide important efficacy and safety information on guselkumab therapy in TNFi-IR patients with PsA. TRIAL REGISTRATION/BACKGROUND:This trial was registered at ClinicalTrials.gov, NCT04936308, on 23 June 2021.

OBJECTIVE:To study the effects of Short Chain Fatty Acids (SCFAs) on arthritic bone remodeling. METHODS:CD4Cre mice, with SCFA supplemented water. We also performed in vitro osteoclast differentiation assays in the presence of serum-level SCFAs to evaluate the direct impact of these microbial metabolites on maturation and function of osteoclasts. We further characterized the molecular mechanism of SCFAs by transcriptional analysis. RESULTS:CD4Cre mice. Further interrogation revealed that bone marrow derived OCPs from diseased mice expressed a higher level of SCFA receptors than that of control mice and that the progenitor cells in the bone marrow of SCFA-treated mice presented a modified transcriptomic landscape, suggesting a direct impact of SCFAs on bone marrow progenitors in the context of osteoporosis. CONCLUSION/CONCLUSIONS:We demonstrated how gut microbiota-derived SCFAs can regulate distal pathology, i.e., osteoporosis, and identified a potential therapeutic option for restoring bone density in rheumatic disease, further highlighting the critical role of the gut-bone axis in these disorders.