Clinical trial parameters that influence outcomes in lupus trials that use the systemic lupus erythematosus responder index.

Objective: The SLE Responder Index (SRI) is a composite endpoint used in SLE trials. This investigation examined the clinical trial elements that drive response measured by the SRI. Methods: Analyses are based on data from two phase 3 trials (n = 2262) that evaluated the impact of an anti-B-cell activating factor antibody on disease activity using SRI-5 as the primary endpoint (ClinicalTrials.gov NCT01196091 and NCT01205438). Results: The SRI-5 response rate at week 52 for all patients was 32.8%. Non-response due to a lack of SLEDAI improvement, concomitant medication non-compliance or dropout was 31, 16.5 and 19.1%, respectively. Non-response due to deterioration in BILAG or Physician's Global Assessment after SLEDAI improvement, concomitant medication compliance and trial completion was 0.5%. Disease activity in three SLEDAI organ systems was highly prevalent at baseline: mucocutaneous, 90.6%; musculoskeletal, 82.9%; and immunologic, 71.6%. Disease activity in each of the other organ systems was <11% of patients. Four clinical manifestations were highly prevalent at baseline: arthritis, 82.6%; rash, 69.2%; alopecia, 58.2%; and mucosal ulcer, 32.5%. The combined prevalence of renal, vascular and CNS disease at baseline was 17.6%; these patients had high SRI-5 response rates. Adjustments to corticosteroids were allowed during the first 24 weeks. Increases in corticosteroids above 2.5 mg/day were observed in 16.2% of placebo patients over the first 24 weeks after randomization. Conclusion: The primary drivers of SRI-5 response were SLEDAI improvement, concomitant medication adherence and trial completion. Arthritis, rash, alopecia and mucosal ulcer were the most prevalent clinical manifestations at baseline. Corticosteroid increases and rare, highly weighted disease manifestations in SLEDAI can confound the SRI signal.

A selective and potent CXCR3 antagonist SCH 546738 attenuates the development of autoimmune diseases and delays graft rejection.

BACKGROUND: The CXCR3 receptor and its three interferon-inducible ligands (CXCL9, CXCL10 and CXCL11) have been implicated as playing a central role in directing a Th1 inflammatory response. Recent studies strongly support that the CXCR3 receptor is a very attractive therapeutic target for treating autoimmune diseases, such as rheumatoid arthritis, multiple sclerosis and psoriasis, and to prevent transplant rejection. We describe here the in vitro and in vivo pharmacological characterizations of a novel and potent small molecule CXCR3 antagonist, SCH 546738. RESULTS: In this study, we evaluated in vitro pharmacological properties of SCH 546738 by radioligand receptor binding and human activated T cell chemotaxis assays. In vivo efficacy of SCH 546738 was determined by mouse collagen-induced arthritis, rat and mouse experimental autoimmune encephalomyelitis, and rat cardiac transplantation models. We show that SCH 546738 binds to human CXCR3 with a high affinity of 0.4 nM. In addition, SCH 546738 displaces radiolabeled CXCL10 and CXCL11 from human CXCR3 with IC50 ranging from 0.8 to 2.2 nM in a non-competitive manner. SCH 546738 potently and specifically inhibits CXCR3-mediated chemotaxis in human activated T cells with IC90 about 10 nM. SCH 546738 attenuates the disease development in mouse collagen-induced arthritis model. SCH 546738 also significantly reduces disease severity in rat and mouse experimental autoimmune encephalomyelitis models. Furthermore, SCH 546738 alone achieves dose-dependent prolongation of rat cardiac allograft survival. Most significantly, SCH 546738 in combination with CsA supports permanent engraftment. CONCLUSIONS: SCH 546738 is a novel, potent and non-competitive small molecule CXCR3 antagonist. It is efficacious in multiple preclinical disease models. These results demonstrate that therapy with CXCR3 antagonists may serve as a new strategy for treatment of autoimmune diseases, including rheumatoid arthritis and multiple sclerosis, and to prevent transplant rejection.

Short-chain fatty acids act as antiinflammatory mediators by regulating prostaglandin E(2) and cytokines.

AIM: To investigate the effect of short-chain fatty acids (SCFAs) on production of prostaglandin E(2) (PGE(2)), cytokines and chemokines in human monocytes. METHODS: Human neutrophils and monocytes were isolated from human whole blood by using 1-Step Polymorph and RosetteSep Human Monocyte Enrichment Cocktail, respectively. Human GPR41 and GPR43 mRNA expression was examined by quantitative real-time polymerase chain reaction. The calcium flux assay was used to examine the biological activities of SCFAs in human neutrophils and monocytes. The effect of SCFAs on human monocytes and peripheral blood mononuclear cells (PBMC) was studied by measuring PGE(2), cytokines and chemokines in the supernatant. The effect of SCFAs in vivo was examined by intraplantar injection into rat paws. RESULTS: Human GPR43 is highly expressed in human neutrophils and monocytes. SCFAs induce robust calcium flux in human neutrophils, but not in human monocytes. In this study, we show that SCFAs can induce human monocyte release of PGE(2) and that this effect can be enhanced in the presence of lipopolysaccharide (LPS). In addition, we demonstrate that PGE(2) production induced by SCFA was inhibited by pertussis toxin, suggesting the involvement of a receptor-mediated mechanism. Furthermore, SCFAs can specifically inhibit constitutive monocyte chemotactic protein-1 (MCP-1) production and LPS-induced interleukin-10 (IL-10) production in human monocytes without affecting the secretion of other cytokines and chemokines examined. Similar activities were observed in human PBMC for the release of PGE(2), MCP-1 and IL-10 after SCFA treatment. In addition, SCFAs inhibit LPS-induced production of tumor necrosis factor-alpha and interferon-gamma in human PBMC. Finally, we show that SCFAs and LPS can induce PGE(2) production in vivo by intraplantar injection into rat paws (P < 0.01). CONCLUSION: SCFAs can have distinct antiinflammatory activities due to their regulation of PGE(2), cytokine and chemokine release from human immune cells.

The pyrimidinergic P2Y6 receptor mediates a novel release of proinflammatory cytokines and chemokines in monocytic cells stimulated with UDP.

The human P2Y6 receptor (hP2Y6) is a member of the G protein-coupled pyrimidinergic P2 receptor family that responds specifically to the extracellular nucleotide uridine diphosphate (UDP). Recently, the hP2Y6 receptor has been reported to mediate monocyte IL-8 production in response to UDP or lipopolysaccharide (LPS), but the role of hP2Y6 in regulating other pro-inflammatory cytokines or mediators is largely unknown. We demonstrate here that UDP specifically induces soluble TNF-alpha and IL-8 production in a promonocytic U937 cell line stably transfected with hP2Y6. However, we did not detect IL-1alpha, IL-1beta, IL-6, IL-10, IL-18, and PGE2 in the conditioned media from the same cell line. These results distinguish UDP/P2Y6 signaling from LPS signaling. Interestingly, UDP induces the production of IL-8, but not TNF-alpha, in human astrocytoma 1321N1 cell lines stably transfected with hP2Y6. Therefore, the immune effect of UDP/P2Y6 signaling on the production of proinflammatory cytokines is selective and dependent on cell types. We further identify that UDP can also induce the production of proinflammatory chemokines MCP-1 and IP-10 in hP2Y6 transfected promonocytic U937 cell lines, but not astrocytoma 1321N1 cell lines stably transfected with hP2Y6. From the Taqman analysis, UDP stimulation significantly upregulates the mRNA levels of IL-8, IP-10, and IL-1beta, but not TNF-alpha. Taken together, these new findings expand the pro-inflammatory biology of UDP mediated by the P2Y6 receptor.