Development of Cilofexor, an intestinally-biased Farnesoid X Receptor agonist, for the treatment of fatty liver disease.

The farnesoid X receptor (FXR) is a nuclear receptor that controls bile acid, lipid, and cholesterol metabolism. FXR-targeted drugs have shown promise in late-stage clinical trials for non-alcoholic steatohepatitis. Herein, we used clinical results from our first non-steroidal FXR agonist, Px-102 (4-[2-[2-chloro-4-[[5-cyclopropyl-3-(2,6-dichlorophenyl)-4-isoxazolyl]methoxy]phenyl]cyclopropyl] benzoic acid), to develop cilofexor, a potent, non-steroidal FXR agonist with a more manageable safety profile. Px-102 demonstrated the anticipated pharmacodynamic (PD) effects in healthy volunteers but caused a 2-fold increase in alanine aminotransferase (ALT) activity and changes in cholesterol levels. These data guided development of a high fat diet mouse model to screen FXR agonists based on ALT and cholesterol changes. Cilofexor was identified to elicit only minor changes in these parameters. The differing effects of cilofexor and Px-102 on ALT/cholesterol in the model could not be explained by potency or specificity, and we hypothesized that the relative contribution of intestinal and liver FXR activation may be responsible. Gene expression analysis from rodent studies revealed that cilofexor, but not Px-102, had a bias for FXR transcriptional activity in the intestine compared to the liver. Fluorescent imaging in hepatoma cells demonstrated similar subcellular localization for cilofexor and Px-102, but cilofexor was more rapidly washed out, consistent with a lower membrane residence time contributing to reduced hepatic transcriptional effects. Cilofexor demonstrated antisteatotic and antifibrotic efficacy in rodent models and antisteatotic efficacy in a monkey model, with the anticipated PD and a manageable safety profile in human phase I studies. Significance Statement FXR (farnesoid X receptor) agonists have shown promise in treating non-alcoholic steatohepatitis and other liver diseases in the clinic, but balancing efficacy with undesired side effects has been difficult. Here, we examined the preclinical and clinical effects of the first-generation FXR agonist, Px-102 (4-[2-[2-chloro-4-[[5-cyclopropyl-3-(2,6-dichlorophenyl)-4-isoxazolyl]methoxy]phenyl]cyclopropyl] benzoic acid), to enable the selection of an analog, cilofexor, with unique properties that reduced side effects yet maintained efficacy. Cilofexor is one of few remaining FXR agonists in clinical development.

The Non-Steroidal FXR Agonist Cilofexor Improves Portal Hypertension and Reduces Hepatic Fibrosis in a Rat NASH Model.

BACKGROUND: The farnesoid X receptor (FXR) influences hepatic metabolism, inflammation and liver fibrosis as key components of non-alcoholic steatohepatitis (NASH). We studied the effects of the non-steroidal FXR agonist cilofexor (formerly GS-9674) on portal pressure and fibrosis in experimental NASH. METHODS: NASH was induced in Wistar rats using a choline-deficient high-fat diet plus intraperitoneal sodium nitrite injections. First, a dose-finding study was performed with 10 mg/kg and 30 mg/kg of cilofexor, focusing on histological readouts. Liver fibrosis was assessed by Picro-Sirius-Red, desmin staining and hepatic hydroxyproline content. Gene expression was determined by RT-PCR. In a subsequent hemodynamic study, rats received 30 mg/kg cilofexor with or without propranolol (25 mg/kg). Portal pressure, systemic hemodynamics and splanchnic blood flow were measured. RESULTS: Cilofexor dose-dependently induced FXR target genes shp, cyp7a1 and fgf15 in hepatic and ileal tissues, paralleled by a dose-dependent reduction in liver fibrosis area (Picro-Sirius-Red) of -41% (10 mg/kg) and -69% (30 mg/kg), respectively. The 30 mg/kg cilofexor dose significantly reduced hepatic hydroxyproline content (-41%), expression of col1a1 (-37%) and pdgfr-ß (-36%), as well as desmin area (-42%) in NASH rats. Importantly, cilofexor decreased portal pressure (11.9 ± 2.1 vs. 8.9 ± 2.2 mmHg; p = 0.020) without affecting splanchnic blood-flow or systemic hemodynamics. The addition of propranolol to cilofexor additionally reduced splanchnic inflow (-28%) but also mean arterial pressure (-25%) and heart rate (-37%). CONCLUSION: The non-steroidal FXR agonist cilofexor decreased portal hypertension and reduced liver fibrosis in NASH rats. While cilofexor seems to primarily decrease sinusoidal resistance in cirrhotic portal hypertension, the combination with propranolol additionally reduced mesenteric hyperperfusion.

The nuclear bile acid receptor FXR controls the liver derived tumor suppressor histidine-rich glycoprotein.

The nuclear bile acid receptor Farnesoid X receptor (FXR) is strongly expressed in liver and intestine, controls bile acid and lipid homeostasis and exerts tumor-protective functions in liver and intestine. Histidine-rich glycoprotein (HRG) is an abundant plasma protein produced by the liver with the proposed function as a pattern recognition molecule involved in the clearance of immune complexes, necrotic cells and pathogens, the modulation of angiogenesis, the normalization of deranged endothelial vessel structure in tumors and tumor suppression. FXR recognition sequences were identified within a human HRG promoter fragment that mediated FXR/FXR-agonist dependent reporter gene activity in vitro. We show that HRG is a novel transcriptional target gene of FXR in human hepatoma cells, human upcyte® primary hepatocytes and 3D human liver microtissues in vitro and in mouse liver in vivo. Prolonged administration of the potent nonsteroidal FXR agonist PX20606 increases HRG levels in mouse plasma. Finally, daily oral administration of this FXR agonist for seven days resulted in a significant increase of HRG levels in the plasma of healthy human male volunteers during a clinical Phase I safety study. HRG might serve as a surrogate marker indicative of liver-specific FXR activation in future human clinical studies. Furthermore, potent FXR agonists might be beneficial in serious health conditions where HRG is reduced, for example, in hepatocellular carcinoma but also other solid cancers, liver failure, sepsis and pre-eclampsia.

Fluorescence characteristics and pharmacokinetic properties of a novel self-adhesive 5-ALA patch for photodynamic therapy of actinic keratoses.

Actinic keratosis (AK) can be treated by photodynamic therapy (PDT), which is becoming a well-established tool in dermatology. Normally a precursor of the photosensitiser is applied topically and converted into protoporphyrin IX (PPIX) in the cells. By activating PPIX with light, the dysplastic cells will be destroyed. We report the results of two clinical studies investigating the properties of a novel self-adhesive 5-ALA-patch (PD P 506 A) intended for PDT of mild to moderate AK on the face and head. The studies investigated the influence of patch application duration on PPIX-specific fluorescence and the pharmacokinetic properties of the 5-ALA patch. The PPIX fluorescence in AK lesions and normal skin after patch application (intraindividual comparison; application for 2, 3, 4, 5 h) was investigated in 13 patients using DYADERM Professional (Biocam). In the subsequent pharmacokinetic study 12 patients were treated with 8 patches each (4 h application). 5-ALA and PPIX were analysed in plasma (over 24 h) and urine (over 12 h). PPIX-specific fluorescence measured immediately after patch removal increased with increasing application duration to a maximum at 4-h application. The fluorescence in AK lesions was more intense than in normal skin. A small increase of 5-ALA plasma concentrations was observed in 10 of 12 patients after applying 8 patches for 4 h, which rapidly declined to normal values after patch removal. The maximum increase was 3.7-fold of the pre-dose 5-ALA plasma concentration. No PPIX-concentrations above the lower limit of quantification were observed. PPIX-specific fluorescence in AK lesions can be steered by application duration of this novel 5-ALA patch. Application is safe and well tolerable. The observed small rise in 5-ALA plasma concentrations is regarded clinically irrelevant. Clinical efficacy of the patch in PDT will be investigated in further clinical trials.

Evaluation of the effect of candesartan cilexetil on the steady-state pharmacokinetics of tacrolimus in renal transplant patients.

BACKGROUND: Candesartan cilexetil is a possible treatment for hypertension in renal allograft recipients. Tacrolimus is widely used as an immunosuppressant following renal transplantation. The aim of this study was to evaluate the effect of multiple doses of candesartan cilexetil on the steady-state pharmacokinetics of tacrolimus. METHODS: Twelve patients received oral doses of tacrolimus twice daily for 12 days from study day -2 until day 10, single oral doses of candesartan cilexetil placebo on study days -2 to -1, single oral doses of 2 mg candesartan cilexetil once daily on study days 1 to 3, oral doses of 4 mg candesartan cilexetil once daily on study days 4 to 6, and oral doses of 16 mg candesartan cilexetil once daily on study days 7 to 9. Serial blood samples were collected on days -1, 6 and 9 and were analysed for tacrolimus using microparticle enzyme immunoassay. RESULTS: Mean C(max,ss) and AUC(tau,ss) values for tacrolimus on day 6 (4 mg candesartan) and day 9 (16 mg candesartan cilexetil) were similar to those on day -1 (tacrolimus alone). Renal function did not change under treatment with candesartan cilexetil compared with baseline. The co-administration of multiple oral doses of cardesartan cilexetil with oral doses of tacrolimus was well tolerated. CONCLUSIONS: Concomitant administration of multiple doses of candesartan cilexetil does not alter the steady-state pharmacokinetics of tacrolimus.

Pharmacokinetic interaction study of a fixed combination of 500 mg acetylsalicylic acid/30 mg pseudoephedrine versus each of the single active ingredients in healthy male volunteers.

UNLABELLED: Acetylsalicylic acid (CAS 50-78-2, ASA) and pseudoephedrine (CAS 90-82-4, PSE) both are remedies given together for the treatment of the symptoms of a common cold, i.e. mainly nasal congestion, running nose, sore throat and headache. The aim of this open, randomized, three-factorial (three-treatment, three-period, six-sequence) Latin Square clinical study was to investigate if there were any pharmacokinetic interactions between ASA and PSE when given as fixed combination of 500 mg ASA/30 mg PSE.HCl. Lack of interaction was assessed by determination of pharmacokinetic characteristics and relative bioavailability of both substances and salicylic acid (CAS 69-72-7, SA), administered in combination and as equally single dosed drugs. In total, the data of 12 healthy male volunteers were included into the pharmacokinetic evaluation. Primary target parameters were ratios combination/equally dosed single drugs of AUCnorm and Cmax, norm of ASA, its metabolite SA and PSE. The primary target parameters were analyzed using an analysis of variance (ANOVA) after logarithmic transformation of the data. 90% confidence intervals were calculated for the geometric means of ratios using the mean square error term of the ANOVA. RESULTS: Bioequivalence was given for AUCnorm and Cmax, norm for all ratios calculated. No interaction was found for AUCnorm and Cmax, norm between the fixed combination ASA/PSE and the equally single dosed drugs as reference. The supplementary evaluation for the non-normalized original parameters AUC and Cmax also revealed bioequivalence. All treatments were safe and well tolerated.