Effects on weight loss and glycemic control with SAR441255, a potent unimolecular peptide GLP-1/GIP/GCG receptor triagonist.

Unimolecular triple incretins, combining the activity of glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and glucagon (GCG), have demonstrated reduction in body weight and improved glucose control in rodent models. We developed SAR441255, a synthetic peptide agonist of the GLP-1, GCG, and GIP receptors, structurally based on the exendin-4 sequence. SAR441255 displays high potency with balanced activation of all three target receptors. In animal models, metabolic outcomes were superior to results with a dual GLP-1/GCG receptor agonist. Preclinical in vivo positron emission tomography imaging demonstrated SAR441255 binding to GLP-1 and GCG receptors. In healthy subjects, SAR441255 improved glycemic control during a mixed-meal tolerance test and impacted biomarkers for GCG and GIP receptor activation. Single doses of SAR441255 were well tolerated. The results demonstrate that integrating GIP activity into dual GLP-1 and GCG receptor agonism provides improved effects on weight loss and glycemic control while buffering the diabetogenic risk of chronic GCG receptor agonism.

Indatuximab ravtansine plus dexamethasone with lenalidomide or pomalidomide in relapsed or refractory multiple myeloma: a multicentre, phase 1/2a study.

BACKGROUND: Indatuximab ravtansine (BT062) is an antibody-drug conjugate that binds to CD138 and synergistically enhances the antitumor activity of lenalidomide in preclinical models of multiple myeloma. This phase 1/2a study was done to determine the safety, activity, and pharmacokinetics of indatuximab ravtansine in combination with immunomodulatory drugs in patients with relapsed or refractory multiple myeloma. METHODS: This open-label, phase 1/2a study took place at nine hospital sites in the USA. Eligible patients were aged 18 years or older, had relapsed or refractory multiple myeloma, and ECOG performance status or Zubrod score of 2 or below. Patients who received indatuximab ravtansine with lenalidomide and dexamethasone (indatuximab ravtansine plus lenalidomide) had failure of at least one previous therapy. Patients treated with indatuximab ravtansine with pomalidomide and dexamethasone (indatuximab ravtansine plus pomalidomide) had failure of at least two previous therapies (including lenalidomide and bortezomib) and had progressive disease on or within 60 days of completion of their last treatment. In phase 1, patients received indatuximab ravtansine intravenously on days 1, 8, and 15 of each 28-day cycle in escalating dose levels of 80 mg/m2, 100 mg/m2, and 120 mg/m2, with lenalidomide (25 mg; days 1 to 21 every 28 days orally) and dexamethasone (20-40 mg; days 1, 8, 15, and 22 every 28 days). In phase 2, the recommended phase 2 dose of indatuximab ravtansine was given to an expanded cohort of patients in combination with lenalidomide and dexamethasone. The protocol was amended to allow additional patients to be treated with indatuximab ravtansine plus pomalidomide (4 mg; days 1 to 21 every 28 days orally) and dexamethasone, in a more heavily pretreated patient population than in the indatuximab ravtansine plus lenalidomide group. The phase 1 primary endpoint was to determine the dose-limiting toxicities and the maximum tolerated dose (recommended phase 2 dose) of indatuximab ravtansine, and the phase 2 primary endpoint was to describe the objective response rate (ORR; partial response or better) and clinical benefit response (ORR plus minor response). All patients were analysed for safety and all patients with post-treatment response assessments were analysed for activity. This study is registered with ClinicalTrials.gov, number NCT01638936, and is complete. FINDINGS: 64 (86%) of 74 screened patients were enrolled between July 3, 2012, and June 30, 2015. 47 (73%) patients received indatuximab ravtansine plus lenalidomide (median follow-up 24·2 months [IQR 19·9-45·4]) and 17 (27%) received indatuximab ravtansine plus pomalidomide (24·1 months [17·7-36·7]). The maximum tolerated dose of indatuximab ravtansine plus lenalidomide was 100 mg/m2, and defined as the recommended phase 2 dose for indatuximab ravtansine plus pomalidomide. An objective response for indatuximab ravtansine plus lenalidomide was observed in 33 (71·7%) of 46 patients and in 12 (70·6%) of 17 patients in the indatuximab ravtansine plus pomalidomide group. The clinical benefit response for indatuximab ravtansine plus lenalidomide was 85% (39 of 46 patients) and for indatuximab ravtansine plus pomalidomide it was 88% (15 of 17 patients). The most common grade 3-4 adverse events in both groups were neutropenia (14 [22%] of 64 patients), anaemia (10 [16%]), and thrombocytopenia (seven [11%]). Treatment-emergent adverse events (TEAEs) that led to discontinuation occurred in 35 (55%) of the 64 patients. Five (8%) patients with a TEAE had a fatal outcome; none was reported as related to indatuximab ravtansine. INTERPRETATION: Indatuximab ravtansine in combination with immunomodulatory drugs shows preliminary antitumor activity, is tolerated, and could be further evaluated in patients with relapsed or refractory multiple myeloma. FUNDING: Biotest AG.

Indatuximab Ravtansine (BT062) Monotherapy in Patients With Relapsed and/or Refractory Multiple Myeloma.

BACKGROUND: Indatuximab ravtansine (BT062) is an antibody-drug conjugate that binds to CD138, which is overexpressed on multiple myeloma (MM) cells. PATIENTS AND METHODS: We report from 2 clinical studies of patients with relapsed and/or refractory MM previously treated with an immunomodulatory drug and a proteasome inhibitor. Single- and multi-dosing schedules were investigated to define dose-limiting toxicities, maximum tolerated dose (MTD), recommended phase II dose, and to describe safety, efficacy, and pharmacokinetics. RESULTS: In the first-in-human study, indatuximab ravtansine was administered to 32 patients on day 1 of each 21-day cycle. The MTD was 160 mg/m2. In the phase I/IIa study, indatuximab ravtansine was administered to 35 patients on days 1, 8, and 15 of each 28-day cycle, and the MTD/recommended phase II dose was 140 mg/m2. Most (88%) adverse events were grade 1 or 2, the most common being diarrhea and fatigue. There was rapid clearance of indatuximab ravtansine and no relevant accumulation. Over 75% of heavily pretreated patients achieved stable disease or better. With the multi-dose schedule, minor and partial responses occurred in 14.7% of patients, the median time to progression was 3 months, and the median overall survival was 26.7 months. CONCLUSION: Our data support further investigation of indatuximab ravtansine as part of a combination regimen for relapsed and/or refractory MM.

Efficacy and safety of tregalizumab in patients with rheumatoid arthritis and an inadequate response to methotrexate: results of a phase IIb, randomised, placebo-controlled trial.

OBJECTIVE: To evaluate the efficacy, biological activity and safety of tregalizumab in patients with active rheumatoid arthritis (RA) and an inadequate response to methotrexate (MTX). METHODS: 321 patients were randomised (1:1:1:1) to placebo or tregalizumab 25, 100 or 200 mg once-weekly subcutaneously in addition to MTX treatment. Responders at week 12 continued the same treatment, and non-responders at week 12 were escalated to the next higher tregalizumab dose level or re-randomised from placebo to active treatment. After 24 weeks, patients could continue treatment with tregalizumab for 24 weeks (extension phase). The primary endpoint was the American College of Rheumatology 20% improvement criteria (ACR20) response rate at week 12. Safety and biological activity were monitored through week 48. RESULTS: At week 12, ACR20 response rates were not statistically significantly different between placebo and any of the tregalizumab doses. Tregalizumab injections were well tolerated; most adverse events were mild to moderate and comparable among treatment and placebo groups. Biological activity was shown by dose-dependent CD4 downmodulation. CONCLUSION: Treatment with tregalizumab did not show significant clinical efficacy in patients with active RA compared with placebo but resulted in the expected biological effect on CD4 modulation. Tregalizumab was generally well tolerated, and no new safety findings were identified. TRIAL REGISTRATION NUMBER: NCT01999192; Results.

Tregalizumab - A Monoclonal Antibody to Target Regulatory T Cells.

Regulatory T cells (Tregs) represent a subpopulation of CD4(+) T cells, which are essential for the maintenance of immunological tolerance. The absence or dysfunction of Tregs can lead to autoimmunity and allergies. The restoration of functional Tregs and/or Treg cell numbers represents a novel and attractive approach for the treatment of autoimmune diseases, e.g., rheumatoid arthritis (RA). The CD4 cell surface receptor is a target for modulation of T cell function. Monoclonal antibodies (mAbs) against CD4 have previously been tested for the treatment of autoimmune diseases, including RA. Furthermore, in model systems, anti-CD4 antibodies are able to induce tolerance and mediate immunomodulatory effects through a variety of mechanisms. Despite the availability of innovative and effective therapies for RA, many patients still have persistently active disease or experience adverse events that can limit use. A growing body of evidence suggests that Treg modulation could offer a new therapeutic strategy in RA and other autoimmune disorders. Here, we describe tregalizumab (BT-061), which is a novel, non-depleting IgG1 mAb that binds to a unique epitope of CD4. Tregalizumab represents the first humanized anti-CD4 mAb that selectively induces Treg activation.

High thioredoxin-1 levels in rheumatoid arthritis patients diminish binding and signalling of the monoclonal antibody Tregalizumab.

The humanized non-depleting anti-CD4 monoclonal antibody Tregalizumab (BT-061) is able to selectively activate the suppressive function of regulatory T cells and has been investigated up to phase IIb in clinical trials in patients suffering from rheumatoid arthritis (RA). A pharmacokinetic-pharmacodynamic model based on clinical data from RA and healthy volunteers, which used the cell surface CD4 downmodulation as marker of activity, confirmed a stronger effect in healthy volunteers compared with RA patients. We tried to understand this phenomenon and evaluated the influence of the small oxidoreductase thioredoxin-1 (Trx1). To counteract oxidative stress that is strongly associated with RA pathophysiology, the organism employs Trx1. Therefore, increased expression and secretion of Trx1 is found in the synovial fluid and plasma of RA patients. Moreover, the binding site of Tregalizumab is in close proximity to a disulphide bond in domain 2 (D2) of CD4, which is a known target for a reduction by oxidoreductase Trx1. With the experiments reported herein, we demonstrated that specific reduction of the D2 disulphide bond by Trx1 led to diminished binding of Tregalizumab to recombinant human soluble CD4 and membrane-bound CD4 on T cells. Moreover, we showed that this caused changes in the Tregalizumab-induced CD4 signalling pathway via the lymphocyte-specific protein tyrosine kinase p56 Lck and CD4 downmodulation. In summary, we provide evidence that high Trx1 levels in RA patients compared with healthy subjects are a potential reason for diminished binding of Tregalizumab to CD4-positive T cells and offer an explanation for the observed decreased CD4 downmodulation in RA patients in comparison to healthy subjects.

A selective inhibitor reveals PI3Kγ dependence of T(H)17 cell differentiation.

We devised a high-throughput chemoproteomics method that enabled multiplexed screening of 16,000 compounds against native protein and lipid kinases in cell extracts. Optimization of one chemical series resulted in CZC24832, which is to our knowledge the first selective inhibitor of phosphoinositide 3-kinase γ (PI3Kγ) with efficacy in in vitro and in vivo models of inflammation. Extensive target- and cell-based profiling of CZC24832 revealed regulation of interleukin-17-producing T helper cell (T(H)17) differentiation by PI3Kγ, thus reinforcing selective inhibition of PI3Kγ as a potential treatment for inflammatory and autoimmune diseases.

Intranasal immunization promotes th17 immune responses.

Th17 cells are a lineage of CD4+ T cells characterized by IL-17 secretion, which plays a crucial role in immune responses against important respiratory pathogens, such as Mycobacterium tuberculosis. In this study, we demonstrated that intranasal (i.n.) immunization leads per se to Th17-biased immune responses, regardless of the adjuvant used. The activated CD4+ T cells also showed an up-regulated expression of the chemokine receptor CCR6, which is a marker for murine Th17 cells. These results have important implications in the context of optimizing rational vaccine design, since i.n. immunization appears to be the strategy of choice for situations where the induction of a Th17 phenotype would be beneficial.

An SopB-mediated immune escape mechanism of Salmonella enterica can be subverted to optimize the performance of live attenuated vaccine carrier strains.

Salmonellae have evolved several mechanisms to evade host clearance. Here, we describe the influence on bacterial immune escape of the effector protein SopB, which is translocated into the cytosol through a type III secretion system. Wild-type bacteria, as well as the sseC and aroA attenuated mutants exerted a stronger cytotoxic effect on dendritic cells (DC) than their SopB-deficient derivatives. Cells infected with the double sseC sopB, phoP sopB and aroA sopB mutants also exhibited higher expression of MHC, CD80, CD86 and CD54 molecules, and showed a stronger capacity to process and present an I-E(d)-restricted epitope from the influenza hemagglutinin (HA) to CD4+ cells from TCR-HA transgenic mice in vitro. The incorporation of an additional mutation into the sopB locus of the attenuated sseC, phoP and aroA mutants resulted in the stimulation of improved humoral and cellular immune responses following oral vaccination. The obtained results define a new potential immune escape strategy of this important pathogen, and also demonstrate that this mechanism can be subverted to optimize the immune responses elicited using Salmonella as a live vaccine carrier.

Characterization of a B220+ lymphoid cell subpopulation with immune modulatory functions in nasal-associated lymphoid tissues.

Complex mechanisms operate on mucosal tissues to regulate immune responsiveness and tolerance. When the lymphocyte subpopulations from murine nasal-associated lymphoid tissues (NALT) were characterized, we observed an accumulation of B220(low)CD3(low)CD4(-)CD8(-)CD19(-)c-Kit(+) cells. TCR transgenic mice and athymic mice were used for monitoring T cell lineage and the presence of extrathymic T cell precursors. The majority of cells from NALT exhibited a T cell precursor phenotype (CD4(-)CD8(-)CD19(-)c-Kit(+)). Fas-independent apoptosis was their main mechanism of cell death. We also demonstrated that B220(low)CD4(-)CD8(-)CD19(-) cells from NALT exhibited the potential to down-regulate the activation of mature T cells. However, the innate immunity receptor TLR2 was also highly expressed by this cell subpopulation. Moreover, nasal stimulation with a TLR2/6 agonist resulted in a partial activation of the double-negative cells. These results suggest that the immune responses in NALT may be in part modulated by a cell subpopulation that maintains a tolerogenic milieu by its proapoptotic status and suppressive activity, which can be reverted through stimulation of a TLR signaling cascade.

The Mycoplasma-derived macrophage-activating 2-kilodalton lipopeptide triggers global immune activation on nasal mucosa-associated lymphoid tissues.

A better knowledge on how immune responses are initiated in mucosal tissues would facilitate the design of new mucosal vaccines, as well as improve our understanding on host defense against infection. We investigated the mechanisms of adjuvanticity of the Mycoplasma-derived macrophage-activating 2-kDa lipopeptide (MALP-2), which binds to the heterodimer formed by the Toll-like receptors 2 and 6 (TLR2 and -6), at the level of the murine nasal mucosa-associated lymphoid tissues (NALT). TLR2 expression analysis demonstrated that several cell types from the nasal cavity were able to overexpress this receptor, either constitutively (such as B cells) or after stimulation (i.e., T cells). MALP-2 stimulated a strong B-cell activation. In addition, the antigen presentation capacity of dendritic cells was improved after in vivo loading with antigen in the presence of MALP-2. We also observed an up-regulated expression of activation markers and adhesion molecules on T cells, suggesting that they have enhanced responsiveness and interaction potential. Quantitative reverse transcription-PCR analysis showed that MALP-2 administration resulted in the stimulation of a proinflammatory cascade. We observed an early up-regulated expression of IP-10, MCP-1, MCP-3, MIP-1alpha, MIP-2, and CCR-2 which was reversed within 36 h. The obtained results demonstrated that MALP-2 creates a reversible local microenvironment which promotes effective priming of T and B cells in the NALT.

Efficient mucosal delivery of the HIV-1 Tat protein using the synthetic lipopeptide MALP-2 as adjuvant.

A major requirement for HIV/AIDS research is the development of a mucosal vaccine that stimulates humoral and cell-mediated immune responses at systemic and mucosal levels, thereby blocking virus replication at the entry port. Thus, a vaccine prototype based on biologically active HIV-1 Tat protein as antigen and the synthetic lipopeptide, macrophage-activating lipopeptide-2 (MALP-2), asa mucosal adjuvant was developed. Intranasal administration to mice stimulated systemic and mucosal anti-Tat antibody responses, and Tat-specific T cell responses, that were more efficient than those observed after i.p. immunization with Tat plus incomplete Freund's adjuvant. Major linear B cell epitopes mapped within aa 1-20 and 46-60, whereas T cell epitopes were identified within aa 36-50 and 56-70. These epitopes have also been described in vaccinated primates and in HIV-1-infected individuals with better prognosis. Analysis of the anti-Tat IgG isotypes in serum, and the cytokine profile of spleen cells indicated that a dominant Th1 helper response was stimulated by Tat plus MALP-2, as opposed to the Th2 response observed with Tat plus incomplete Freund's adjuvant. Tat-specific IFN-gamma-producing cells were significantly increased only in response to Tat plus MALP-2. These data suggest that Malp-2 may represent an optimal mucosal adjuvant for candidate HIV vaccines based on Tat alone or in combination with other HIV antigens.

The Mycoplasma-derived lipopeptide MALP-2 is a potent mucosal adjuvant.

The adjuvanticity of MALP-2, a 2-kDa synthetic lipopeptide with macrophage-stimulatory activity, was evaluated in BALB/c mice using beta-galactosidase (beta-gal) as model antigen. When co-administered with beta-gal by either the intranasal (i.n.) or i.p. route, MALP-2 (0.5 microg) was capable of increasing beta-gal-specific serum IgG titers by 675-3,560-fold (i.n.) and 64-128-fold (i.p.), respectively, as compared to immunization with beta-gal alone. Using MALP-2, almost maximal IgG responses were already stimulated following the first immunization, and the IgG titers were similar to those observed using 10 microg of cholera toxin B subunit (CTB) as adjuvant. The mucosal immune system was also effectively stimulated (p<0.05) when MALP-2 was administered by the i.n. route (36% and 23% of beta-gal-specific IgA in lung and vaginal lavages, respectively). The i.n. co-administration of MALP-2 stimulated a stronger cellular immune response than CTB, both in submandibular lymph nodes and spleen (p<0.05). The analysis of beta-gal-specific IgG isotypes and the profiles of cytokines secreted by in vitro re-stimulated cells showed that co-administration of MALP-2 triggered a dominant Th2-response pattern. A recruitment of B220(+) and MAC-1(+) cells with an up-regulated expression of MHC class I, CD80 (B7.1) and CD54 (ICAM-1) was observed in nasal associated lymphoid tissues from MALP-2 treated mice. Taken together, our results demonstrated that the synthetic lipopeptide MALP-2 represents a very promising adjuvant for the mucosal delivery of vaccine antigens.

Characterization of a novel intracellularly activated gene from Salmonella enterica serovar typhi.

A Salmonella enterica serovar Typhi gene that is selectively up-regulated upon bacterial invasion of eukaryotic cells was characterized. The open reading frame encodes a 298-amino-acid hydrophobic polypeptide (30.8 kDa), which is predicted to be an integral membrane protein with nine membrane-spanning domains. The protein is closely related (87 to 94% reliability) to different transport and permease systems. Gene expression under laboratory conditions was relatively weak; however, sevenfold induction was observed in a high-osmolarity medium (300 mM NaCl). The growth pattern in a laboratory medium of a serovar Typhi strain Ty2 derivative containing a 735-bp in-frame deletion in this gene, named gaiA (for gene activated intracellularly), was not affected. In contrast, the mutant was partially impaired in intracellular survival in murine peritoneal macrophages, as well as in human monocyte-derived macrophages. However, in the case of human macrophages, this survival defect was modest and evident only at late infection times (24 h). Despite the distinct intracellular survival kinetics displayed in macrophages of different species, the gaiA null mutant was significantly affected in its potential to trigger apoptosis in both murine and human macrophages. Provision of the gaiA gene in trans resulted in complementation of these phenotypes. Interestingly, the absence of a functional gaiA gene caused a marked attenuation in the mouse mucin model, as shown by the increase (3 orders of magnitude) in the 50% lethal dose of the mutant strain over that of the parental strain Ty2 (P