Gerard Bruin

Effects of AIN457, a Fully Human Antibody to Interleukin-17A, on Psoriasis, Rheumatoid Arthritis, and Uveitis

A human antibody to interleukin-17A is well tolerated and may be effective in the treatment of psoriasis, rheumatoid arthritis, and noninfectious uveitis. Stopping Inflammation in Its Tracks Inflammation—characterized by redness, swelling, and pain and derived from the Latin word inflammare (to set on fire)—is the body’s principal defense against infection and injury. Once the infection has been squelched by the immune system, the inflammatory response is usually switched off. Sometimes, however, immune cells activated during inflammation elude the “off switch,” resulting in tissue destruction and various diseases—including cancer, rheumatoid arthritis, and skin disorders such as psoriasis. Cytokines that activate immune cells are key drivers of inflammation. To address whether blocking one of these cytokines, interleukin-17A (IL-17A), might be a useful therapeutic strategy for treating inflammatory diseases, Hueber and colleagues used a human monoclonal antibody (AIN457) against IL-17A to treat patients in three small proof-of-concept trials for psoriasis, rheumatoid arthritis, and uveitis (eye inflammation). Their results demonstrate that IL-17A participates in these diseases and that the antibody against this cytokine may be an effective therapeutic agent. The proinflammatory cytokine IL-17A is produced by T helper 17 (TH17) cells and affects many different cell types including macrophages and dendritic cells of the immune system, as well as epithelial, endothelial, and skin cells. IL-17A has been implicated in psoriasis, rheumatoid arthritis, and uveitis, but its exact role is unclear. The etiologies and symptoms of these three diseases are very different. TH17 and TH1 cells have been implicated in both psoriasis (characterized by excessive turnover of skin cells resulting in scaly skin patches) and uveitis (intraocular inflammation that can lead to vision loss). In contrast, in the autoimmune disease rheumatoid arthritis, autoreactive T and B cells together with autoantibodies promote prolonged inflammation, ultimately resulting in the destruction of cartilage and bone. In their three proof-of-concept trials, Hueber and co-workers treated a total of 60 patients with the human monoclonal antibody AIN457 at different doses and observed no major adverse effects. Although the trials were small and the results were preliminary, improvements were seen in all three disease groups. Psoriasis patients receiving AIN457 showed reduced scaly skin patches, decreased production of inflammatory cytokines, and a reduction in T cells infiltrating the skin lesions compared with placebo-treated patients. After receiving infusions of AIN457, rheumatoid arthritis patients exhibited reduced inflammation of the synovial joints as shown by improvements in three different clinical scores compared with placebo-treated patients. Meanwhile, patients with uveitis treated with AIN457 showed improved visual acuity, reduced ocular inflammation, or a reduced need for steroid drugs after 8 weeks. These encouraging results warrant larger clinical trials to assess further the safety and efficacy of AIN457 for treating psoriasis, rheumatoid arthritis, and uveitis and perhaps other inflammatory diseases in which IL-17A has been implicated. Interleukin-17A (IL-17A) is elaborated by the T helper 17 (TH17) subset of TH cells and exhibits potent proinflammatory properties in animal models of autoimmunity, including collagen-induced arthritis, experimental autoimmune encephalomyelitis, and experimental autoimmune uveitis. To determine whether IL-17A mediates human inflammatory diseases, we investigated the efficacy and safety of AIN457, a human antibody to IL-17A, in patients with psoriasis, rheumatoid arthritis, and chronic noninfectious uveitis. Patients with chronic plaque-type psoriasis (n = 36), rheumatoid arthritis (n = 52), or chronic noninfectious uveitis (n = 16) were enrolled in clinical trials to evaluate the effects of neutralizing IL-17A by AIN457 at doses of 3 to 10 mg/kg, given intravenously. We evaluated efficacy by measuring the psoriasis area and severity index (PASI), the American College of Rheumatology 20% response (ACR20) for rheumatoid arthritis, or the number of responders for uveitis, as defined by either vision improvement or reduction in ocular inflammation or corticosteroid dose. AIN457 treatment induced clinically relevant responses of variable magnitude in patients suffering from each of these diverse immune-mediated diseases. Variable response rates may be due to heterogeneity in small patient populations, differential pathogenic roles of IL-17A in these diseases, and the different involvement or activation of IL-17A–producing cells. The rates of adverse events, including infections, were similar in the AIN457 and placebo groups. These results support a role for IL-17A in the pathophysiology of diverse inflammatory diseases including psoriasis, rheumatoid arthritis, and noninfectious uveitis.

Secukinumab, a human anti-IL-17A monoclonal antibody, for moderate to severe Crohn's disease: unexpected results of a randomised, double-blind placebo-controlled trial

Objective The authors tested whether the anti-interleukin (IL)-17A monoclonal antibody secukinumab was safe and effective for the treatment of active Crohns disease. Design In a double-blind, randomised, placebo-controlled proof-of-concept study, 59 patients with moderate to severe Crohns disease (Crohns Disease Activity Index (CDAI) ≥220 to ≤450) were assigned in a 2:1 ratio to 2×10 mg/kg intravenous secukinumab or placebo. The primary end point, addressed by Bayesian statistics augmented with historical placebo information, was the probability that secukinumab reduces the CDAI by ≥50 points more than placebo at week 6. Ancillary analyses explored associations of 35 candidate genetic polymorphisms and faecal calprotectin response. Results 59 patients (39 secukinumab, 20 placebo, mean baseline CDAI 307 and 301, respectively) were recruited. 18/59 (31%) patients discontinued prematurely (12/39 (31%) secukinumab, 6/20 (30%) placebo), 10/59 (17%) due to insufficient therapeutic effect (8/39 (21%) secukinumab, 2/20 (10%) placebo). Fourteen serious adverse events occurred in 10 patients (seven secukinumab, three placebo); 20 infections, including four local fungal infections, were seen on secukinumab versus none on placebo. Primary end point analysis estimated <0.1% probability (∆CDAI (SD) =33.9 (19.7), 95% credible interval −4.9 to 72.9) that secukinumab reduces CDAI by ≥50 points more than placebo. Secondary area under the curve analysis (weeks 4–10) showed a significant difference (mean ΔCDAI=49; 95% CI (2 to 96), p=0.043) in favour of placebo. Post hoc subgroup analysis showed that unfavourable responses on secukinumab were driven by patients with elevated inflammatory markers (CRP≥10 mg/l and/or faecal calprotectin≥200 ng/ml; mean ΔCDAI=62; 95% CI (−1 to 125), p=0.054 in favour of placebo). Absence of the minor allele of tumour necrosis factor-like ligand 1A was strongly associated with lack of response measured by baseline-adjusted changes in calprotectin at week 6 (p=0.00035 Bonferroni-corrected). Conclusions Blockade of IL-17A was ineffective and higher rates of adverse events were noted compared with placebo. Clinical trial registration This trial was registered at ClinicalTrial.gov with the number NCT01009281.

Recent developments in electrokinetically driven analysis on microfabricated devices

This review is devoted to the rapid developments in the field of microfluidic separation devices in which the flow is electrokinetically driven, and where the separation element forms the heart of the system, in order to give an overview of the trends of the last three years. Examples of microchip layouts that were designed for various application areas are given. Optimization of mixing and injection strategies, designs for the handling of multiple samples, and capillary array systems show the enormous progress made since the first proof‐of‐concept papers about lab‐on‐a‐chip devices. Examples of functional elements for on‐chip preconcentration, filtering, DNA amplification and on‐chip detection indicate that the real integration of various analytical tasks on a single microchip is coming into reach. The use of materials other than glass, such as poly(dimethylsiloxane) and polymethylmethacrylate, for chip fabrication and detection methods other than laser‐induced fluorescence (LIF) detection, such as mass spectrometry and electrochemical detection, are described. Furthermore, it can be observed that the separation modes known from capillary electrophoresis (CE) in fused‐silica capillaries can be easily transferred to the microchip platform. The review concludes with an overview of applications of microchip CE and with a brief outlook.

Fritless capillary electrochromatography.

The preparation of packed capillaries with stable frits of good quality can be a hurdle to obtain efficient separations in capillary electrochromatography (CEC). Especially with particles smaller than 3 μm, frit preparation is cumbersome. Highly efficient separations using packed capillaries without frits are presented. Under appropriate CEC conditions the particles were retained by electrophoretic attraction towards the anode by a tapered capillary inlet, without the need of a frit at the outlet end. Such fritless capillaries, packed with 1.5 μm nonporous reversed‐phase particles, allowed separations with efficiencies of more than 500 000 plates/m. Once the capillaries were conditioned properly, more than 100 separations could be performed with good repeatability. With respect to separation efficiency, fritless capillaries packed with 3 μm particles were comparable with standard CEC capillaries with frits. Examples of separations of steroids, a pesticide and its by‐products, and cardiac glycosides under various CEC conditions are shown.

Pharmacokinetics, metabolism, and disposition of deferasirox in beta-thalassemic patients with transfusion-dependent iron overload who are at pharmacokinetic steady state.

Deferasirox (ICL670) is a novel once-daily, orally administered iron chelator to treat chronic iron overload in patients with transfusion-dependent anemias. Absorption, distribution, metabolism, and excretion of [14C]deferasirox at pharmacokinetic steady state was investigated in five adult β-thalassemic patients. Deferasirox (1000 mg) was given orally once daily for 6 days to achieve steady state. On day 7, patients received a single oral 1000-mg dose (∼20 mg/kg) of [14C]deferasirox (2.5 MBq). Blood, plasma, feces, and urine samples collected over 7 days were analyzed for radioactivity, deferasirox, its iron complex Fe-[deferasirox]2, and metabolites. Deferasirox was well absorbed. Deferasirox and its iron complex accounted for 87 and 10%, respectively, of the radioactivity in plasma (area under the curve at steady state). Excretion occurred largely in the feces (84% of dose), and 60% of the radioactivity in the feces was identified as deferasirox. Apparently unchanged deferasirox in feces was partly attributable to incomplete intestinal absorption and partly to hepatobiliary elimination of deferasirox (including first-pass elimination) and of its glucuronide. Renal excretion was only 8% of the dose and included mainly the glucuronide M6. Oxidative metabolism by cytochrome 450 enzymes to M1 [5-hydroxy (OH) deferasirox, presumably by CYP1A] and M4 (5′-OH deferasirox, by CYP2D6) was minor (6 and 2% of the dose, respectively). Direct and indirect evidence indicates that the main pathway of deferasirox metabolism is via glucuronidation to metabolites M3 (acyl glucuronide) and M6 (2-O-glucuronide).

ATF936, a novel oral calcilytic, increases bone mineral density in rats and transiently releases parathyroid hormone in humans.

Parathyroid hormone (PTH), when injected daily as either the intact hormone PTH(1-84) or the active fragment PTH(1-34) (teriparatide), is an efficacious bone anabolic treatment option for osteoporosis patients. Injections lead to rapid and transient spikes in hormone exposure levels, a profile which is a prerequisite to effectively form bone. Oral antagonists of the calcium-sensing receptor (calcilytics) stimulate PTH secretion and represent thus an alternative approach to elevate hormone levels transiently. We report here on ATF936, a novel calcilytic, which triggered rapid, transient spikes in endogenous PTH levels when given orally in single doses of 10 and 30mg/kg to growing rats, and of 1mg/kg to dogs. Eight weeks daily oral application of 30mg/kg of ATF936 to aged female rats induced in the proximal tibia metaphysis increases in bone mineral density, cancellous bone volume and cortical and trabecular thickness as evaluated by computed tomography. In healthy humans, single oral doses of ATF936 produced peak PTH levels in plasma after a median time of 1h and levels returned to normal at 24-h post-dose. The average maximum PTH concentration increase from baseline was 1.9, 3.6, and 6.0-fold at doses of 40, 70, and 140mg. ATF936 was well tolerated. The sharp, transient increase in PTH levels produced by the oral calcilytic ATF936 was comparable to the PTH profile observed after subcutaneous administration of teriparatide. In conclusion, ATF936 might hold potential as an oral bone-forming osteoporosis therapy.

β-Defensin 2 is a responsive biomarker of IL-17A-driven skin pathology in patients with psoriasis.

Background: IL‐17A is a key driver of human autoimmune diseases, particularly psoriasis. Objective: We sought to determine the role of IL‐17A in psoriasis pathogenesis and to identify a robust and measurable biomarker of IL‐17A–driven pathology. Methods: We studied 8 healthy subjects and 8 patients with psoriasis before and after administration of secukinumab, a fully human anti–IL‐17A mAb, and used a combination of classical techniques and a novel skin microperfusion assay to evaluate the expression of 170 proteins in blood, nonlesional skin, and lesional skin. For validation, we also tested stored sera from 601 patients with a variety of autoimmune diseases. Results: IL‐17A was specifically expressed in lesional compared with nonlesional psoriatic skin (9.8 vs 0.8 pg/mL, P < .001). Proteomic and gene transcription analyses revealed dysregulated antimicrobial peptides, proinflammatory cytokines, and neutrophil chemoattractants, levels of which returned to normal after treatment with secukinumab. &bgr;‐Defensin 2 (BD‐2) was identified as a biomarker of IL‐17A–driven pathology by comparing protein expression in patients with psoriasis versus that in healthy subjects (5746 vs 82 pg/mL in serum, P < .0001; 2747 vs <218 pg/mL in dermis, P < .001), responsiveness to secukinumab therapy, and synergistic induction by IL‐17A and TNF‐&agr; in epidermal keratinocytes. In a validation set of sera from 601 patients with autoimmune diseases thought to be IL‐17A driven, we found that BD‐2 levels are most highly increased in patients with psoriatic skin lesions, and in patients with psoriasis, BD‐2 levels correlated well with IL‐17A levels (r = 0.70, n = 199, P < .001) and Psoriasis Area and Severity Index scores (r = 0.53, n = 281, P < .001). Conclusion: IL‐17A is a primary driver of skin pathology in patients with psoriasis, and serum BD‐2 is an easily measurable biomarker of IL‐17A–driven skin pathology.

AXT914 a novel, orally-active parathyroid hormone-releasing drug in two early studies of healthy volunteers and postmenopausal women

Antagonism of the calcium-sensing receptor in the parathyroid gland leads to parathyroid hormone (PTH) release. Calcilytics are a new class of molecules designed to exploit this mechanism. In order to mimic the known bone-anabolic pharmacokinetic (PK) profile of s.c. administered PTH, such molecules must trigger sharp, transient and robust release of PTH. The results of two early clinical studies with the orally-active calcilytic AXT914, a quinazolin-2ne derivative are reported. These were GCP-compliant, single and multiple dose studies of PK/PD and tolerability in healthy volunteers and postmenopausal women. The first study, examined single ascending doses (4 to 120 mg) and limited multiple doses (60 or 120 mgq.d. for 12 days) of AXT914. The second study was a randomized, double-blind, active- and placebo-controlled, 4-week repeat-dose parallel group study of healthy postmenopausal women (45 and 60 mg AXT914, placebo, 20 μg Forteo/teriparatide/PTH(1-34) fragment). AXT914 was well tolerated at all doses and reproducibly induced the desired PTH-release profiles. Yet, 4 weeks of 45 or 60 mg AXT914 did not result in the expected changes in circulating bone biomarkers seen with teriparatide. However total serum calcium levels increased above baseline in the 45 and 60 mg AXT914 treatment groups (8.0% and 10.7%, respectively), compared to that in the teriparatide and placebo groups (1.3% and 1.0%, respectively). Thus the trial was terminated after a planned interim analysis due to lack of effect on bone formation biomarkers and dose-limiting effects on serum calcium. In conclusion, AXT914 was well tolerated but the observed transient and reproducible PTH-release after repeat oral administration of AXT914 which showed an exposure profile close to that of s c. PTH, did not translate into a bone anabolic response and was associated with a persistent dose-related increase in serum calcium concentrations.

Secukinumab, a fully human anti-interleukin-17a monoclonal antibody, exhibits minimal immunogenicity in patients with moderate-to-severe plaque psoriasis

The proinflammatory cytokine interleukin (IL)‐17A plays a pivotal role in psoriasis pathogenesis. Secukinumab, a fully human monoclonal antibody (mAb) that selectively targets IL‐17A, has been demonstrated to be highly efficacious for the treatment of moderate‐to‐severe psoriasis, starting at early time points, with a sustained effect and a favourable safety profile. mAb therapies may be associated with production of antidrug antibodies (ADAs) that can affect drug pharmacokinetics, diminish response or cause hypersensitivity reactions.

Secukinumab distributes into dermal interstitial fluid of psoriasis patients as demonstrated by open flow microperfusion

1 Vanbokhoven H, Melino G, Candi E et al. J Invest Dermatol 2011: 131: 1196–1207. 2 Koster M I, Kim S, Mills A A et al. Genes Dev 2004: 18: 126–131. 3 Nelson A M, Reddy S K, Ratliff T S et al. Cell Stem Cell 2015: 17: 139–151. 4 Su X, Paris M, Gi Y J et al. Cell Stem Cell 2009: 5: 64–75. 5 Koster M I, Roop D R. Cell Cycle 2004: 3: 411– 413. 6 Chu W K, Dai P M, Li H L et al. J Biol Chem 2008: 283: 7328–7337. 7 Yang J, Liao X, Agarwal M K et al. Genes Dev 2007: 21: 1396–1408. 8 Battle T E, Frank D A. Curr Mol Med 2002: 2: 381–392. 9 Hagihara K, Nishikawa T, Sugamata Y et al. Genes Cells 2005: 10: 1051–1063.