Mouse IL-2/CD25 Fusion Protein Induces Regulatory T Cell Expansion and Immune Suppression in Preclinical Models of Systemic Lupus Erythematosus.

Systemic lupus erythematosus (SLE) is associated with an IL-2-deficient state, with regulatory T cells (Tregs) showing diminished immune regulatory capacity. A low dose of IL-2 has shown encouraging clinical benefits in SLE patients; however, its clinical utility is limited because of the requirement of daily injections and the observation of increase in proinflammatory cytokines and in non-Tregs. We recently showed that a fusion protein of mouse IL-2 and mouse IL-2Rα (CD25), joined by a noncleavable linker, was effective in treating diabetes in NOD mice by selectively inducing Treg expansion. In this report, we show that mouse IL-2 (mIL-2)/CD25 at doses up to 0.5 mg/kg twice a week induced a robust Treg expansion without showing signs of increase in the numbers of NK, CD4+Foxp3-, or CD8+ T cells or significant increase in proinflammatory cytokines. In both NZB × NZW and MRL/lpr mice, mIL-2/CD25 at 0.2-0.4 mg/kg twice a week demonstrated efficacy in inducing Treg expansion, CD25 upregulation, and inhibiting lupus nephritis based on the levels of proteinuria, autoantibody titers, and kidney histology scores. mIL-2/CD25 was effective even when treatment was initiated at the time when NZB × NZW mice already showed signs of advanced disease. Furthermore, we show coadministration of prednisolone, which SLE patients commonly take, did not interfere with the ability of mIL-2/CD25 to expand Tregs. The prednisolone and mIL-2/CD25 combination treatment results in improvements in most of the efficacy readouts relative to either monotherapy alone. Taken together, our results support further evaluation of IL-2/CD25 in the clinic for treating immune-mediated diseases such as SLE.

Identification of N-Methyl Nicotinamide and N-Methyl Pyridazine-3-Carboxamide Pseudokinase Domain Ligands as Highly Selective Allosteric Inhibitors of Tyrosine Kinase 2 (TYK2).

As a member of the Janus (JAK) family of nonreceptor tyrosine kinases, TYK2 plays an important role in mediating the signaling of pro-inflammatory cytokines including IL-12, IL-23, and type 1 interferons. The nicotinamide 4, identified by a SPA-based high-throughput screen targeting the TYK2 pseudokinase domain, potently inhibits IL-23 and IFNα signaling in cellular assays. The described work details the optimization of this poorly selective hit (4) to potent and selective molecules such as 47 and 48. The discoveries described herein were critical to the eventual identification of the clinical TYK2 JH2 inhibitor (see following report in this issue). Compound 48 provided robust inhibition in a mouse IL-12-induced IFNγ pharmacodynamic model as well as efficacy in an IL-23 and IL-12-dependent mouse colitis model. These results demonstrate the ability of TYK2 JH2 domain binders to provide a highly selective alternative to conventional TYK2 orthosteric inhibitors.

Highly Selective Inhibition of Tyrosine Kinase 2 (TYK2) for the Treatment of Autoimmune Diseases: Discovery of the Allosteric Inhibitor BMS-986165.

Small molecule JAK inhibitors have emerged as a major therapeutic advancement in treating autoimmune diseases. The discovery of isoform selective JAK inhibitors that traditionally target the catalytically active site of this kinase family has been a formidable challenge. Our strategy to achieve high selectivity for TYK2 relies on targeting the TYK2 pseudokinase (JH2) domain. Herein we report the late stage optimization efforts including a structure-guided design and water displacement strategy that led to the discovery of BMS-986165 (11) as a high affinity JH2 ligand and potent allosteric inhibitor of TYK2. In addition to unprecedented JAK isoform and kinome selectivity, 11 shows excellent pharmacokinetic properties with minimal profiling liabilities and is efficacious in several murine models of autoimmune disease. On the basis of these findings, 11 appears differentiated from all other reported JAK inhibitors and has been advanced as the first pseudokinase-directed therapeutic in clinical development as an oral treatment for autoimmune diseases.

Autoimmune pathways in mice and humans are blocked by pharmacological stabilization of the TYK2 pseudokinase domain.

TYK2 is a nonreceptor tyrosine kinase involved in adaptive and innate immune responses. A deactivating coding variant has previously been shown to prevent receptor-stimulated activation of this kinase and provides high protection from several common autoimmune diseases but without immunodeficiency. An agent that recapitulates the phenotype of this deactivating coding variant may therefore represent an important advancement in the treatment of autoimmunity. BMS-986165 is a potent oral agent that similarly blocks receptor-stimulated activation of TYK2 allosterically and with high selectivity and potency afforded through optimized binding to a regulatory domain of the protein. Signaling and functional responses in human TH17, TH1, B cells, and myeloid cells integral to autoimmunity were blocked by BMS-986165, both in vitro and in vivo in a phase 1 clinical trial. BMS-986165 demonstrated robust efficacy, consistent with blockade of multiple autoimmune pathways, in murine models of lupus nephritis and inflammatory bowel disease, supporting its therapeutic potential for multiple immune-mediated diseases.

Discovery of Branebrutinib (BMS-986195): A Strategy for Identifying a Highly Potent and Selective Covalent Inhibitor Providing Rapid in Vivo Inactivation of Bruton's Tyrosine Kinase (BTK).

Bruton's tyrosine kinase (BTK), a non-receptor tyrosine kinase, is a member of the Tec family of kinases and is essential for B cell receptor (BCR) mediated signaling. BTK also plays a critical role in the downstream signaling pathways for the Fcγ receptor in monocytes, the Fcε receptor in granulocytes, and the RANK receptor in osteoclasts. As a result, pharmacological inhibition of BTK is anticipated to provide an effective strategy for the clinical treatment of autoimmune diseases such as rheumatoid arthritis and lupus. This article will outline the evolution of our strategy to identify a covalent, irreversible inhibitor of BTK that has the intrinsic potency, selectivity, and pharmacokinetic properties necessary to provide a rapid rate of inactivation systemically following a very low dose. With excellent in vivo efficacy and a very desirable tolerability profile, 5a (branebrutinib, BMS-986195) has advanced into clinical studies.

Identification and Preclinical Pharmacology of ((1 R,3 S)-1-Amino-3-(( S)-6-(2-methoxyphenethyl)-5,6,7,8-tetrahydronaphthalen-2-yl)cyclopentyl)methanol (BMS-986166): A Differentiated Sphingosine-1-phosphate Receptor 1 (S1P1) Modulator Advanced into Clinical Trials.

Recently, our research group reported the identification of BMS-986104 (2) as a differentiated S1P1 receptor modulator. In comparison to fingolimod (1), a full agonist of S1P1 currently marketed for the treatment of relapse remitting multiple sclerosis (RRMS), 2 offers several potential advantages having demonstrated improved safety multiples in preclinical evaluations against undesired pulmonary and cardiovascular effects. In clinical trials, 2 was found to exhibit a pharmacokinetic half-life ( T1/2) longer than that of 1, as well as a reduced formation of the phosphate metabolite that is required for activity against S1P1. Herein, we describe our efforts to discover highly potent, partial agonists of S1P1 with a shorter T1/2 and increased in vivo phosphate metabolite formation. These efforts culminated in the discovery of BMS-986166 (14a), which was advanced to human clinical evaluation. The pharmacokinetic/pharmacodynamic (PK/PD) relationship as well as pulmonary and cardiovascular safety assessments are discussed. Furthermore, efficacy of 14a in multiple preclinical models of autoimmune diseases are presented.

Bruton's tyrosine kinase inhibitor BMS-986142 in experimental models of rheumatoid arthritis enhances efficacy of agents representing clinical standard-of-care.

Bruton's tyrosine kinase (BTK) regulates critical signal transduction pathways involved in the pathobiology of rheumatoid arthritis (RA) and other autoimmune disorders. BMS-986142 is a potent and highly selective reversible small molecule inhibitor of BTK currently being investigated in clinical trials for the treatment of both RA and primary Sjögren's syndrome. In the present report, we detail the in vitro and in vivo pharmacology of BMS-986142 and show this agent provides potent and selective inhibition of BTK (IC50 = 0.5 nM), blocks antigen receptor-dependent signaling and functional endpoints (cytokine production, co-stimulatory molecule expression, and proliferation) in human B cells (IC50 ≤ 5 nM), inhibits Fcγ receptor-dependent cytokine production from peripheral blood mononuclear cells, and blocks RANK-L-induced osteoclastogenesis. Through the benefits of impacting these important drivers of autoimmunity, BMS-986142 demonstrated robust efficacy in murine models of rheumatoid arthritis (RA), including collagen-induced arthritis (CIA) and collagen antibody-induced arthritis (CAIA). In both models, robust efficacy was observed without continuous, complete inhibition of BTK. When a suboptimal dose of BMS-986142 was combined with other agents representing the current standard of care for RA (e.g., methotrexate, the TNFα antagonist etanercept, or the murine form of CTLA4-Ig) in the CIA model, improved efficacy compared to either agent alone was observed. The results suggest BMS-986142 represents a potential therapeutic for clinical investigation in RA, as monotherapy or co-administered with agents with complementary mechanisms of action.

Identification of potent tricyclic prodrug S1P1 receptor modulators.

Recently, our research group reported the identification of prodrug amino-alcohol 2 as a potent and efficacious S1P1 receptor modulator. This molecule is differentiated preclinically over the marketed drug fingolimod (Gilenya 1), whose active phosphate metabolite is an S1P1 full agonist, in terms of pulmonary and cardiovascular safety. S1P1 partial agonist 2, however, has a long half-life in rodents and was projected to have a long half-life in humans. The purpose of this communication is to disclose highly potent partial agonists of S1P1 with shorter half-lives relative to the clinical compound 2. PK/PD relationships as well as their preclinical pulmonary and cardiovascular safety assessment are discussed.

Asymmetric Hydroboration Approach to the Scalable Synthesis of ((1R,3S)-1-Amino-3-((R)-6-hexyl-5,6,7,8-tetrahydronaphthalen-2-yl)cyclopentyl)methanol (BMS-986104) as a Potent S1P1 Receptor Modulator.

We describe a highly efficient route for the synthesis of 4a (BMS-986104). A key step in the synthesis is the asymmetric hydroboration of trisubstituted alkene 6. Particularly given the known difficulties involved in this type of transformation (6 → 7), the current methodology provides an efficient approach to prepare this class of compounds. In addition, we disclose the efficacy of 4a in a mouse EAE model, which is comparable to 4c (FTY720). Mechanistically, 4a exhibited excellent remyelinating effects on lysophosphatidylcholine (LPC) induced demyelination in a three-dimensional brain cell culture assay.

Discovery of 6-Fluoro-5-(R)-(3-(S)-(8-fluoro-1-methyl-2,4-dioxo-1,2-dihydroquinazolin-3(4H)-yl)-2-methylphenyl)-2-(S)-(2-hydroxypropan-2-yl)-2,3,4,9-tetrahydro-1H-carbazole-8-carboxamide (BMS-986142): A Reversible Inhibitor of Bruton's Tyrosine Kinase (BTK) Conformationally Constrained by Two Locked Atropisomers.

Bruton's tyrosine kinase (BTK), a nonreceptor tyrosine kinase, is a member of the Tec family of kinases. BTK plays an essential role in B cell receptor (BCR)-mediated signaling as well as Fcγ receptor signaling in monocytes and Fcε receptor signaling in mast cells and basophils, all of which have been implicated in the pathophysiology of autoimmune disease. As a result, inhibition of BTK is anticipated to provide an effective strategy for the clinical treatment of autoimmune diseases such as lupus and rheumatoid arthritis. This article details the structure-activity relationships (SAR) leading to a novel series of highly potent and selective carbazole and tetrahydrocarbazole based, reversible inhibitors of BTK. Of particular interest is that two atropisomeric centers were rotationally locked to provide a single, stable atropisomer, resulting in enhanced potency and selectivity as well as a reduction in safety liabilities. With significantly enhanced potency and selectivity, excellent in vivo properties and efficacy, and a very desirable tolerability and safety profile, 14f (BMS-986142) was advanced into clinical studies.

Identification and Preclinical Pharmacology of BMS-986104: A Differentiated S1P1 Receptor Modulator in Clinical Trials.

Clinical validation of S1P receptor modulation therapy was achieved with the approval of fingolimod (Gilenya, 1) as the first oral therapy for relapsing remitting multiple sclerosis. However, 1 causes a dose-dependent reduction in the heart rate (bradycardia), which occurs within hours after first dose. We disclose the identification of clinical compound BMS-986104 (3d), a novel S1P1 receptor modulator, which demonstrates ligand-biased signaling and differentiates from 1 in terms of cardiovascular and pulmonary safety based on preclinical pharmacology while showing equivalent efficacy in a T-cell transfer colitis model.

Dual Inhibition of Interleukin-23 and Interleukin-17 Offers Superior Efficacy in Mouse Models of Autoimmunity.

Therapies targeting either interleukin (IL)-23 or IL-17 have shown promise in treating T helper 17 (Th17)-driven autoimmune diseases. Although IL-23 is a critical driver of IL-17, recognition of nonredundant and independent functions of IL-23 and IL-17 has prompted the notion that dual inhibition of both IL-23 and IL-17 could offer even greater efficacy for treating autoimmune diseases relative to targeting either cytokine alone. To test this hypothesis, we generated selective inhibitors of IL-23 and IL-17 and tested the effect of either treatment alone compared with their combination in vitro and in vivo. In vitro, using a novel culture system of murine Th17 cells and NIH/3T3 fibroblasts, we showed that inhibition of both IL-23 and IL-17 completely suppressed IL-23-dependent IL-22 production from Th17 cells and cooperatively blocked IL-17-dependent IL-6 secretion from the NIH/3T3 cells to levels below either inhibitor alone. In vivo, in the imiquimod induced skin inflammation model, and in the myelin oligodendrocyte glycoprotein peptide-induced experimental autoimmune encephalomyelitis model, we demonstrated that dual inhibition of IL-17 and IL-23 was more efficacious in reducing disease than targeting either cytokine alone. Together, these data support the hypothesis that neutralization of both IL-23 and IL-17 may provide enhanced benefit against Th17 mediated autoimmunity and provide a basis for a therapeutic strategy aimed at dual targeting IL-23 and IL-17.