The PKC-θ isoform of protein kinase C is selectively expressed in T lymphocytes and plays an important role in the T cell antigen receptor (TCR)-triggered activation of mature T cells, T cell proliferation, and the subsequent release of cytokines such as interleukin-2 (IL-2). Herein, we report the synthesis and structure-activity relationship (SAR) of a novel series of PKC-θ inhibitors. Through a combination of structure-guided design and exploratory SAR, suitable replacements for the basic C4 amine of the original lead (3) were identified. Property-guided design enabled the identification of appropriately substituted C2 groups to afford potent analogs with metabolic stability and permeability to support in vivo testing. With exquisite general kinase selectivity, cellular inhibition of T cell activation as assessed by IL-2 expression, a favorable safety profile, and demonstrated in vivo efficacy in models of acute and chronic T cell activation with oral dosing, CC-90005 (57) was selected for clinical development.

Clinical development of BTK kinase inhibitors for treating autoimmune diseases has lagged behind development of these drugs for treating cancers, due in part from concerns over the lack of selectivity and associated toxicity profiles of first generation drug candidates when used in the long term treatment of immune mediated diseases. Second generation BTK inhibitors have made great strides in limiting off-target activities for distantly related kinases, though they have had variable success at limiting cross-reactivity within the more closely related TEC family of kinases. We investigated the BTK specificity and toxicity profiles, drug properties, disease associated signaling pathways, clinical indications, and trial successes and failures for the 13 BTK inhibitor drug candidates tested in phase 2 or higher clinical trials representing 7 autoimmune and 2 inflammatory immune-mediated diseases. We focused on rheumatoid arthritis (RA), multiple sclerosis (MS), and systemic lupus erythematosus (SLE) where the majority of BTK nonclinical and clinical studies have been reported, with additional information for pemphigus vulgaris (PV), Sjogren's disease (SJ), chronic spontaneous urticaria (CSU), graft versus host disease (GVHD), and asthma included where available. While improved BTK selectivity versus kinases outside the TEC family improved clinical toxicity profiles, less profile distinction was evident within the TEC family. Analysis of genetic associations of RA, MS, and SLE biomarkers with TEC family members revealed that BTK and TEC family members may not be drivers of disease. They are, however, mediators of signaling pathways associated with the pathophysiology of autoimmune diseases. BTK in particular may be associated with B cell and myeloid differentiation as well as autoantibody development implicated in immune mediated diseases. Successes in the clinic for treating RA, MS, PV, ITP, and GVHD, but not for SLE and SJ support the concept that BTK plays an important role in mediating pathogenic processes amenable to therapeutic intervention, depending on the disease. Based on the data collected in this study, we propose that current compound characteristics of BTK inhibitor drug candidates for the treatment of autoimmune diseases have achieved the selectivity, safety, and coverage requirements necessary to deliver therapeutic benefit.

Spebrutinib (CC-292) is an orally administered, covalent, small-molecule inhibitor of Bruton’s tyrosine kinase (BTK), part of the B-cell and Fc receptor signaling pathways. This study evaluated spebrutinib pharmacology and mechanism of action over a 4-week treatment period in patients with active rheumatoid arthritis (RA). Primary human B cells, T cells, natural killer cells, macrophages, dendritic cells, basophils, and osteoclasts were treated with spebrutinib in vitro. Clinical pharmacodynamics were studied in 47 patients with active RA on background methotrexate therapy randomized to oral spebrutinib 375 mg/day or placebo. In vitro, spebrutinib inhibited B-cell proliferation more potently than T-cell proliferation and reduced both lymphoid and myeloid cytokine production and degranulation, as well as osteoclastogenesis. Clinical efficacy trended higher in spebrutinib-treated RA patients, with 41.7% (10/24) achieving ≥ 20% improvement in ACR response criteria (ACR20) versus 21.7% (5/23) of placebo patients at week 4 (P = 0.25). Treatment-emergent adverse events were comparable between treatment groups. In spebrutinib-treated patients, median BTK occupancy in peripheral blood was 83%, and significant increases in total CD19+ and mature-naive CD27−CD38−IgD+ B cells and decreases in transitional CD27−CD38+ B cells were observed. Spebrutinib significantly reduced serum chemokines chemokine ligand 13 (CXCL13), macrophage inflammatory protein-1β (MIP-1β), and the bone resorption biomarker carboxy-terminal collagen cross-linking telopeptide (CTX-I) (P < 0.05). Clinical response to spebrutinib was associated with lower increases in CD19+ B cells and greater decreases in CXCL13 and MIP-1β from baseline to week 4. High CD19+ B cells and low CTX-I at baseline were associated with better spebrutinib clinical response. Spebrutinib inhibited various leukocyte responses in vitro, including those of B cells and osteoclasts. In this small study in RA patients, spebrutinib was well tolerated, showed a downward trend for symptoms, significantly modulated B-cell populations, and reduced markers of chemotaxis and osteoclast activity. NCT01975610.

Objectives IKZF1 and IKZF3 (encoding transcription factors Ikaros and Aiolos) are susceptibility loci for systemic lupus erythematosus (SLE). The pharmacology of iberdomide (CC-220), a cereblon (CRBN) modulator targeting Ikaros and Aiolos, was studied in SLE patient cells and in a phase 1 healthy volunteer study. Methods CRBN, IKZF1 and IKZF3 gene expression was measured in peripheral blood mononuclear cells (PBMC) from patients with SLE and healthy volunteers. Ikaros and Aiolos protein levels were measured by Western blot and flow cytometry. Anti-dsDNA and anti-phospholipid autoantibodies were measured in SLE PBMC cultures treated for 7 days with iberdomide. Fifty-six healthy volunteers were randomised to a single dose of iberdomide (0.03-6 mg, n=6 across seven cohorts) or placebo (n=2/cohort). CD19+ B cells, CD3+ T cells and intracellular Aiolos were measured by flow cytometry. Interleukin (IL)-2 and IL-1 beta production was stimulated with anti-CD3 and lipopolysaccharide, respectively, in an ex vivo whole blood assay. Results SLE patient PBMCs expressed significantly higher CRBN (1.5-fold), IKZF1 (2.1-fold) and IKZF3 (4.1-fold) mRNA levels compared with healthy volunteers. Iberdomide significantly reduced Ikaros and Aiolos protein levels in B cells, T cells and monocytes. In SLE PBMC cultures, iberdomide inhibited anti-dsDNA and anti-phospholipid autoantibody production (IC50 approximate to 10 nM). Single doses of iberdomide (0.3-6 mg) in healthy volunteers decreased intracellular Aiolos (minimum mean per cent of baseline: approximate to 12%-28% (B cells); approximate to 0%-33% (T cells)), decreased absolute CD19+ B cells, increased IL-2 and decreased IL-1 beta production ex vivo. Conclusions These findings demonstrate pharmacodynamic activity of iberdomide and support its further clinical development for the treatment of SLE.

BAFF is a B cell survival and maturation factor implicated in the pathogenesis of systemic lupus erythematosus (SLE). In this in vitro study, we describe that soluble BAFF in combination with IL-2 and IL-21 is a T cell contact-independent inducer of human B cell proliferation, plasmablast differentiation, and IgG secretion from circulating CD27(+) memory and memory-like CD27(-) IgD(-) double-negative (DN) B cells, but not CD27(-) IgD(+) naive B cells. In contrast, soluble CD40L in combination with IL-2 and IL-21 induces these activities in both memory and naive B cells. Blood from healthy donors and SLE patients have similar circulating levels of IL-2, whereas SLE patients exhibit elevated BAFF and DN B cells and reduced IL-21. B cell differentiation transcription factors in memory, DN, and naive B cells in SLE show elevated levels of Aiolos, whereas Ikaros levels are unchanged. Treatment with CC-220, a modulator of the cullin ring ligase 4-cereblon E3 ubiquitin ligase complex, reduces Aiolos and Ikaros protein levels and BAFF- and CD40L-induced proliferation, plasmablast differentiation, and IgG secretion. The observation that the soluble factors BAFF, IL-2, and IL-21 induce memory and DN B cell activation and differentiation has implications for extrafollicular plasmablast development within inflamed tissue. Inhibition of B cell plasmablast differentiation by reduction of Aiolos and Ikaros may have utility in the treatment of SLE, where elevated levels of BAFF and Aiolos may prime CD27+ memory and DN memory-like B cells to become Ab-producing plasmablasts in the presence of BAFF and proinflammatory cytokines.

Teriflunomide is an oral disease-modifying therapy recently approved in several locations for relapsing-remitting multiple sclerosis. To gain insight into the effects of teriflunomide, immunocyte population changes were measured during progression of experimental autoimmune encephalomyelitis in Dark Agouti rats. Treatment with teriflunomide attenuated levels of spinal cord-infiltrating T cells, natural killer cells, macrophages, and neutrophils. Teriflunomide also mitigated the disease-induced changes in immune cell populations in the blood and spleen suggesting an inhibitory effect on pathogenic immune responses.

Teriflunomide is an inhibitor of dihydro-orotate dehydrogenase (DHODH), and is hypothesized to ameliorate multiple sclerosis by reducing proliferation of stimulated lymphocytes. We investigated teriflunomide's effects on proliferation, activation, survival, and function of stimulated human peripheral blood mononuclear cell subsets in vitro. Teriflunomide had little/no impact on lymphocyte activation but exerted significant dose-dependent inhibition of T- and B-cell proliferation, which was uridine-reversible (DHODH-dependent). Viability analyses showed no teriflunomide-associated cytotoxicity. Teriflunomide significantly decreased release of several pro-inflammatory cytokines from activated monocytes in a DHODH-independent fashion. In conclusion, teriflunomide acts on multiple immune cell types and processes via DHODH-dependent and independent mechanisms.

Alzheimer's disease (AD) is characterized by neuropil threads composed of structurally abnormal neurites, neurons containing paired helical filaments of tau protein, and extracellular deposits of amyloid-beta (Abeta) peptide, a protein fragment having neurotoxic and glial immune response activating potential. In the present study, we demonstrate that an acute intracerebroventricular (icv) injection of Abeta(1-42) in the mouse induces a time- and dose-dependent production of IL-1alpha, IL-1beta, IL-6 and MCP-1 in the hippocampus and cortex as measured by ELISA. Cytokine and chemokine levels were maximal at 9 h, with MCP-1 and IL-1alpha remaining elevated over a 24 h period and IL-1beta remaining elevated over a 48 h period. The temporal profile of Abeta-induced cytokine induction differed from that observed for LPS. Following an icv injection of LPS, maximal levels of IL-1alpha, IL-1beta, IL-6 and MCP-1 were attained by 9 h and, except for MCP-1, returned to levels indistinguishable from control at 24 h. MCP-1 remained elevated at 24 h and returned to basal levels at 48 h. In contrast, little production of TNF-alpha was observed under either Abeta or LPS acute stimulus conditions. Treatment with anti-inflammatory agents such as prednisolone, dexamethasone, or IL-10 inhibited both Abeta- and LPS-induced cytokine and chemokine production in the brain. In summary, icv administration of Abeta and LPS induced elevated brain levels of pro-inflammatory cytokines that could be inhibited by immune suppressing drugs and anti-inflammatory proteins, thus providing support for the utility of anti-inflammatory therapeutics in modulating the immunopathology observed in brain inflammatory diseases such as AD.

Brain inflammation is typically involved in the pathogenesis of acute conditions such as stroke and brain trauma and in chronic neurodegenerative diseases, for instance, Alzheimer’s disease. Accordingly, a well-characterized in vivo model of brain inflammation can be a useful tool to evaluate specific drug effects focused on various inflammation targets in the pharmaceutical drug discovery process. A model of brain inflammation was induced by the injection of β-amyloid peptide (αβ) or the bacterial endotoxin lipopolysaccharide (LPS) into the lateral ventricles of CD-I mice. The time course and dose response kinetics of cytokine and chemokine production were characterized. Levels of the pro-inflammatory cytokines IL-1α, IL-1β, IL-6 and the chemokine MCP-1 were significantly increased with respect to both time and dose in the cortex and hippocampus as determined by ELISA. Immunohistochemical assays were developed to detect IL-1β to determine cellular localization of this cytokine to microglia and astrocytes. Astrocytes were labeled with antibodies to glial fibrillary acidic protein (GFAP) and microglia were labeled with F4/80 antibodies. IL-1β was localized to cell type in frozen sections using double immunofluorescence (IMF) tags and were visualized with traditional fluorescence and confocal imaging.

Annals of the New York Academy of SciencesVolume 903, Issue 1 p. 529-534 Glial Modulating and Neurotrophic Properties of Propentofylline and Its Application to Alzheimer's Disease and Vascular Dementia GARTH E. RINGHEIM, Corresponding Author GARTH E. RINGHEIM Department of Neuroscience, Aventis Pharmaceuticals, Inc., Bridgewater, New Jersey 08807, USA Address for correspondence: Garth E. Ringheim, Department of Neuroscience, Aventis Pharmaceuticals, Inc., Route 202–206, Bridgewater, NJ 08807. Tel.: (908) 231–4928; fax: (908) 231–4335. e-mail: [email protected]Search for more papers by this author GARTH E. RINGHEIM, Corresponding Author GARTH E. RINGHEIM Department of Neuroscience, Aventis Pharmaceuticals, Inc., Bridgewater, New Jersey 08807, USA Address for correspondence: Garth E. Ringheim, Department of Neuroscience, Aventis Pharmaceuticals, Inc., Route 202–206, Bridgewater, NJ 08807. Tel.: (908) 231–4928; fax: (908) 231–4335. e-mail: [email protected]Search for more papers by this author First published: 30 January 2006 https://doi.org/10.1111/j.1749-6632.2000.tb06409.xCitations: 14Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Citing Literature Volume903, Issue1VASCULAR FACTORS IN ALZHEIMER'S DISEASEApril 2000Pages 529-534 RelatedInformation

Astrocytes in culture have been previously shown to express inducible nitric oxide synthase (iNOS) following treatment with cytokines such as interleukin-1β (IL-1β) and interferon-γ (IFN-γ). We report here on the effects of the cyclic nucleotide analogues 8-bromo-cyclic AMP and 8-bromo-cyclic GMP on cytokine-stimulated iNOS gene expression in a cultured murine astrocyte cell line. In these cells, neither 8-bromo-cyclic AMP nor 8-bromo-cyclic GMP alone was able to stimulate iNOS activity. Similarly, neither IL-1β nor IFN-γ was capable of independently stimulating iNOS expression. Co-stimulation with both cytokines, however, resulted in measurable increases in iNOS activity, and correlated to increases in iNOS mRNA levels. The addition of 8-bromo-cyclic AMP, but not 8-bromo-cyclic GMP, was found to further enhance the expression of iNOS activity induced by IL-1β and IFN-γ co-stimulation. This potentiation effect of 8-bromo-cyclic AMP correlated to a further elevation in iNOS mRNA levels over that produced by cytokine co-stimulation alone. However, 8-bromo-cyclic AMP co-treatment with either cytokine alone did not stimulate iNOS activity, indicating that the signal transduction pathway(s) involved in the potentiation effect of 8-bromo-cyclic AMP is functional only in the presence of both cytokines. These results indicate that cyclic AMP-mediated processes can participate in modulating the expression of astrocyte iNOS when the appropriate combinations of stimulatory cytokines are present. © 1997 Elsevier Science Ltd. All rights reserved

The activation of cultured Raw 264.7 murine macrophages with interferon gamma and lipopolysaccharide results in the expression of inducible nitric oxide synthase (i_NOS) and the subsequent production of nitric oxide. In the present study, the i-NOS expressed in these activated cells was characterized for possible post-translational protein modification by endogenous tyrosine protein kinases. Western-blot analysis using phosphotyrosine antibodies revealed that i-NOS was phosphorylated on tyrosine residues and that this was an early event coinciding with the appearance of newly synthesized i-NOS. A brief exposure of activated cells to vanadate, a tyrosine phosphatase inhibitor, significantly increased the level of i-NOS tyrosine phosphorylation, suggesting that tyrosine phosphatases are dynamically involved in the regulation of this process. Vanadate treatment of activated cells also resulted in a rapid increase in enzyme activity, occurring within 5 min of exposure. Taken together, these results demonstrate that tyrosine kinases and phosphatases are involved in the post-translational modification of i-NOS and may potentially play a role in modulating the functional activity of the enzyme in macrophages.