Replacement of mycophenolate mofetil with a JAK inhibitor, AS2553627, in combination with low-dose tacrolimus, for renal allograft rejection in non-human primates.

In renal transplant patients, using mycophenolate mofetil (MMF) with calcineurin inhibitors (CNIs; cyclosporine and tacrolimus [TAC]) has led to a significant improvement in graft survival. However, reducing or withholding MMF due to its gastrointestinal adverse events increases rejection risk. CNI-sparing strategies are important to avoid CNI-related nephrotoxicity in clinical settings. Here, we investigated AS2553627, a JAK inhibitor replacing MMF in combination with a sub-therapeutic dose of TAC to treat allograft rejection in a monkey model. AS2553627 inhibited proliferation of IL-2 stimulated T cells with little species difference between monkeys and humans. In MMF monotherapy, oral administration of 20 or 40 mg/kg/day prolonged graft survival with median survival times (MSTs) of 16.5 days and 33 days, respectively, whereas untreated animals showed MST of 6 days. In MMF/TAC (1 mg/kg/day, p.o.) combination therapy, pharmacokinetic analysis indicated that MMF 20 mg/kg/day achieved the clinical target AUC0-24h and prolonged renal allograft survival, with MST of 24 days. Oral administration of AS2553627 0.24 mg/kg/day in combination with TAC significantly prolonged renal allograft survival to MST of >90 days with low plasma creatinine levels. Histopathological analysis revealed that acute T cell-mediated rejection events such as vasculitis and interstitial mononuclear cell infiltration were significantly inhibited in AS2553627/TAC-treated allografts compared with MMF/TAC-treated allografts. All AS2553627/TAC-treated monkeys surviving >90 days exhibited less interstitial fibrosis/tubular atrophy than monkeys in the MMF/TAC group. These results suggest that AS2553627 replacing MMF is an attractive CNI-sparing strategy to prevent renal allograft rejection.

Optimization and in vivo evaluation of pyrazolopyridines as a potent and selective PI3Kδ inhibitor.

Chemical optimization of pyrazolopyridine 1, focused on cellular potency, isoform selectivity and microsomal stability, led to the discovery of the potent, selective and orally available PI3Kδ inhibitor 5d. On the basis of its desirable potency, selectivity and pharmacokinetic profiles, 5d was tested in the trinitrophenylated aminoethylcarboxymethyl-Ficoll (TNP-Ficoll)-induced antibody production model, and showed higher antibody inhibition than a 4-fold oral dose of the starting compound 1. These excellent results suggest that 5d is a potential candidate for further studies in the treatment of autoimmune diseases and leukocyte malignancies.

A sphingosine-1-phosphate receptor type 1 agonist, ASP4058, suppresses intracranial aneurysm through promoting endothelial integrity and blocking macrophage transmigration.

BACKGROUND AND PURPOSE: Intracranial aneurysm (IA), common in the general public, causes lethal subarachnoid haemorrhage on rupture. It is, therefore, of utmost importance to prevent the IA from rupturing. However, there is currently no medical treatment. Recent studies suggest that IA is the result of chronic inflammation in the arterial wall caused by endothelial dysfunction and infiltrating macrophages. The sphingosine-1-phosphate receptor type 1 (S1P1 receptor) is present on the endothelium and promotes its barrier function. Here we have tested the potential of an S1P1 agonist, ASP4058, to prevent IA in an animal model. EXPERIMENTAL APPROACH: The effects of a selective S1P1 agonist, ASP4058, on endothelial permeability and migration of macrophages across an endothelial cell monolayer were tested in vitro using a Transwell system, and its effects on the size of IAs were evaluated in a rat model of IA. KEY RESULTS: S1P1 receptor was expressed in endothelial cells of human IA lesions and control arterial walls. ASP4058 significantly reduced FITC-dextran leakage through an endothelial monolayer and suppressed the migration of macrophages across the monolayer in vitro. Oral administration of ASP4058 reduced the vascular permeability, macrophage infiltration and size of the IAs by acting as an S1P1 agonist in the rat model. This effect was mimicked by another two structurally-unrelated S1P1 agonists. CONCLUSION AND IMPLICATIONS: A selective S1P1 agonist is a strong drug candidate for IA treatment as it promotes the endothelial cell barrier and suppresses the trans-endothelial migration of macrophages in IA lesions.

AS1069562, the (+)-isomer of indeloxazine, exerts analgesic effects in a rat model of neuropathic pain with unique characteristics in spinal monoamine turnover.

AS1069562 [(R)-2-[(1H-inden-7-yloxy)methyl]morpholine monobenzenesulfonate] is the (+)-isomer of indeloxazine, which had been used clinically for the treatment of cerebrovascular diseases with multiple pharmacological actions, including serotonin (5-HT) and norepinephrine (NE) reuptake inhibition. Here we investigated the analgesic effects of AS1069562 in a rat model of chronic constriction injury (CCI)-induced neuropathic pain and the spinal monoamine turnover. These effects were compared with those of the antidepressants duloxetine and amitriptyline. AS1069562 significantly elevated extracellular 5-HT and NE levels in the rat spinal dorsal horn, although its 5-HT and NE reuptake inhibition was much weaker than that of duloxetine in vitro. In addition, AS1069562 increased the ratio of the contents of both 5-HT and NE to their metabolites in rat spinal cord, whereas duloxetine slightly increased only the ratio of the content of 5-HT to its metabolite. In CCI rats, AS1069562 and duloxetine significantly ameliorated mechanical allodynia, whereas amitriptyline did not. AS1069562 and amitriptyline significantly ameliorated thermal hyperalgesia, and duloxetine tended to ameliorate it. Furthermore, AS1069562, duloxetine, and amitriptyline significantly improved spontaneous pain-associated behavior. In a gastric emptying study, AS1069562 affected gastric emptying at the same dose that exerted analgesia in CCI rats. On the other hand, duloxetine and amitriptyline significantly reduced gastric emptying at lower doses than those that exerted analgesic effects. These results indicate that AS1069562 broadly improved various types of neuropathic pain-related behavior in CCI rats with unique characteristics in spinal monoamine turnover, suggesting that AS1069562 may have potential as a treatment option for patients with neuropathic pain, with a different profile from currently available antidepressants.

AS1069562, the (+)-isomer of indeloxazine, but not duloxetine has a curative-like analgesic effect in a rat model of streptozotocin-induced diabetic neuropathy.

AS1069562 is the (+)-isomer of indeloxazine, which had been clinically used as a cerebral activator for the treatment of cerebrovascular diseases with serotonin and norepinephrine reuptake inhibition (SNRI) and neuroprotection. Here, we compared the analgesic effects of repeated treatment with AS1069562 and duloxetine, a selective SNRI, on pain-related behavior in a rat model of streptozotocin (STZ)-induced diabetic neuropathy. Further, we also evaluated the effects on the expression of neurotrophic factors and nerve conduction velocity. AS1069562 and duloxetine by single daily administration for 4 weeks significantly improved mechanical allodynia in STZ-induced diabetic rats and did not affect plasma glucose level or body weight. Interestingly, the analgesic effect of AS1069562 continued after a consecutive 1-week treatment discontinuation, although the plasma concentration of AS1069562 was reduced to undetectable levels. In contrast, the efficacy of duloxetine disappeared after treatment discontinuation. Expression analysis demonstrated that AS1069562 significantly restored decreased insulin-like growth factor 1 and fibroblast growth factor 2 mRNA levels in dorsal root ganglion and spinal cord, respectively, whereas duloxetine did not affect the expression levels of neurotrophic factors. In addition, AS1069562 reversed the slowing of nerve conduction velocity. The results of this study indicate that the analgesic effect of repeated dosing of AS1069562 but not duloxetine is persistent even after a 1-week drug discontinuation in STZ-induced diabetic rats. Restoration of neurotrophic factors may be involved in the curative-like pharmacological effect of this agent. Thus, AS1069562 may potentially offer a better treatment option for patients with painful diabetic neuropathy than duloxetine via different mechanisms.

Exploratory population pharmacokinetics (e-PPK) analysis for predicting human PK using exploratory ADME data during early drug discovery research.

We have proposed a novel method by population pharmacokinetics analysis for forecasting the drug concentration time-course in humans. This method is based on the non-linear mixed effect model (NONMEM) combined with in vitro-in vivo extrapolation (IVIVE). Eleven clinically tested compounds were selected for retrospective analysis. The in vivo pharmacokinetic (pk) profiles (rats, dogs, monkeys, and humans) and in vitro ADME data [intrinsic clearance (CLint), plasma unbound fraction (fp), and blood-plasma partition ratio (Rb)] for each compound was routinely tested via a screening system to account for inter-compound differences in pk properties. When evaluating the pk parameters, the hepatic plasma flow (Qph) and plasma volume (Vp) were taken into account to compensate for differences in body size among species. All these data were used to conduct population pk (PPK) analyses under the hypothesis that all species constituted one population. The two-compartment model (ADVAN4 TRANS3) and NONMEM software were used for this analysis. The fixed effect model for total body clearance (CL) and central distribution volume (Vd) were constructed as theta(CL)Qph x Eh and theta(Vd) x Vp, respectively, where the hepatic extraction ratio Eh was calculated using the traditional dispersion model. NONMEM generates both fixed and random effects (eta). The key point of this concept was to substitute the eta values of each species (rats, dogs, and monkeys) into the human PPK model to simulate three kinds of pk profiles, compound by compound, for use as a general scaling factor. The NONMEM post hoc option was used to perform the simulation, after which the concentration vs. time courses were compared with actual clinical pk data. The true values were almost within the dynamic range. Thus, the advantage of this concept is that it can generate time-courses without the detail of drug-specific parameters, from which the elimination half time can be determined. This proposed exploratory population pharmacokinetic (e-PPK) approach is a useful and progressive tool that can be applied during the early stages of drug discovery research.