Days Of Daily Dosing Research Articles

A Placebo-Controlled, Multiple Ascending Dose Study to Evaluate the Safety, Pharmacokinetics and Pharmacodynamics of Avagacestat (BMS-708163) in Healthy Young and Elderly Subjects

Avagacestat is an orally active γ-secretase inhibitor that selectively inhibits amyloid β (Aβ) synthesis in cell culture and animal models. The objective of the current study was to assess the pharmacokinetics, pharmacodynamics, safety and tolerability of multiple doses of avagacestat over 28 days in healthy young men and elderly men and women in a placebo-controlled, sequential-panel, ascending multiple-dose study. Thirty-three young men were assigned to four serial dose groups of avagacestat 15, 50, 100 or 150 mg (n = 6-7 per dose), or placebo (n = 2 per dose panel; 8 subjects total) once daily for 28 days. Elderly men and women were assigned to serial dose groups of avagacestat 50 mg and then 100 mg (n = 7 men, 6 women) or placebo (n = 2 men, 2 women) once daily for 14 days per dose level. Avagacestat was rapidly absorbed, had a terminal elimination half-life of 38-65 h, and reached a steady-state concentration by day 10 of daily dosing. Exposure in young subjects increased in proportion to dose. There were no apparent differences in steady-state area under the plasma concentration-time curve between young and elderly subjects; however, elderly subjects demonstrated a higher maximum plasma concentration for avagacestat. Doses of avagacestat >50 mg/day reduced steady-state trough concentrations of CSF Aβ(1-38), Aβ(1-40) and Aβ(1-42) in a dose-dependent fashion over 28 days of daily dosing. There were no signs of potential Notch-related dose-limiting toxicities. The results support continued evaluation of avagacestat in an elderly target population with predementia and mild to moderate Alzheimer's disease.

Multiple ascending dose study of BMS-790052, a nonstructural protein 5A replication complex inhibitor, in patients infected with hepatitis C virus genotype 1

The antiviral activity, resistance profile, pharmacokinetics (PK), safety, and tolerability of BMS-790052, a nonstructural protein 5A (NS5A) replication complex inhibitor, were evaluated in a double-blind, placebo-controlled, sequential panel, multiple ascending dose study. Thirty patients with chronic hepatitis C virus (HCV) genotype 1 infection were randomized to receive a 14-day course of BMS-790052 (1, 10, 30, 60, or 100 mg once daily or 30 mg twice daily) or placebo in a ratio of 4:1. The mean maximum decline from baseline in HCV RNA ranged from 2.8 to 4.1 log(10) IU/mL; the placebo group showed no evidence of antiviral activity. Most patients experienced viral rebound on or before day 7 of treatment with BMS-790052 monotherapy; viral rebound was associated with viral variants that had been previously implicated in resistance development in the in vitro replicon system. The PK profile was supportive of once-daily dosing with median peak plasma concentrations at 1-2 hours postdose and mean terminal half-life of 12-15 hours. Steady state was achieved following 3-4 days of daily dosing. BMS-790052 was well tolerated in all dose groups, with adverse events occurring with a similar frequency in BMS-790052- and placebo-treated groups. There were no clinically relevant changes in vital signs, laboratory, or electrocardiogram parameters. BMS-7590052 is the first NS5A replication complex inhibitor with multiple dose proof-of-concept in clinic. At doses of 1-100 mg daily, BMS-790052 was well tolerated, had a PK profile supportive of once-daily dosing, and produced a rapid and substantial decrease in HCV-RNA levels in patients chronically infected with HCV genotype 1.

Absorption, distribution, metabolism, and excretion of [1- 14C]-perfluorohexanoate ([ 14C]-PFHx) in rats and mice

The absorption, tissue distribution, elimination, and metabolism of [1- 14C]-PFHx in rats and mice dosed orally at 2 or 100 mg/kg was evaluated following a single dose or after 14 consecutive doses. Absorption was rapid in rats as evidenced by a short time to maximum concentration ( C max) of 30 min in male rats and 15 min in female rats at both the 2 and 100 mg/kg dose level. The plasma elimination half-life was somewhat longer in males (1.5–1.7 h) than in females (0.5–0.7 h). Absorption in the mouse was also rapid with the maximum plasma concentration occurring between 15 and 30 min after dosing. The maximum concentration was not appreciably different between male and female mice (8 μg equiv./g at 2 mg/kg; ∼350 μg equiv./g at 100 mg/kg). The primary route of elimination was via the urine. PFHx was not metabolized in rat or mouse hepatocytes, nor were any metabolites observed after oral dosing in either rodent species. Essentially 100% of the dose was eliminated in urine within 24 h demonstrating that PFHx is readily absorbed and bioavailability approaches 100%, even at a dose as high as 100 mg/kg. The route and extent of elimination was unchanged after 14 days of daily dosing. Tissues were collected at three time points (rat: 0.5, 2, and 24 h; mice: 0.25, 1, and 24 h) after dosing to investigate the tissue clearance kinetics of PFHx following a single dose at 2 or 100 mg/kg. In all tissues except skin, PFHx was not quantifiable 24 h after dosing in both sexes of the two species.

The Activity of Proximal Tubule Enzymes in the Urine of Cephalexin-Treated Patients

The Activity of Proximal Tubule Enzymes in the Urine of Cephalexin-Treated PatientsThe activities of alanine aminopeptidase (AAP), γ-glutamyltransferase (GGT) and N-acetyl-β-D-glucosaminidase (NAG), enzymes dominantly localised in the epithelial proximal tubule cells, were measured with an aim of determining the nephrotoxicity of a cephalosporin antibiotic cephalexin. Enzymatic activities were measured in the 12-h urine samples of patients receiving cephalexin orally for 15 days in daily doses of 50 mg/kg body mass against Gram-positive infections of the respiratory or urinary tract. The same enzymes were determined in the 12-h urine samples of the corresponding control. Both the control and the experimental group consisted of 30 examinees of both sexes, age range 3-10 years. Statistically significant differences in AAP and GGT activities expressed as U/mmol creatinine were recorded after 12 days of cephalexin therapy in comparison with the control (p < 0.01). At the same time, no significant differences in NAG activity of the patients in relation to the control were observed during the entire course of the therapy. Based on the obtained results it can be concluded that treatment of 3-10 years old patients with the applied cephalexin doses for 15 days results in mild nephrotoxic changes close to the end of therapy accompanied by increased activities of AAP and GGT, the enzymes known as very sensitive indicators of nephrotoxicity. The results showing that during the entire period of cephalexin application no changes in NAG, as a lysosomal enzyme, were observed, could be taken as a proof that this antibiotic did not lead to severe injuries of epithelial proximal tubule cells at the level of cell organelles.

Impulsiveness, overactivity, and poorer sustained attention improve by chronic treatment with low doses of l-amphetamine in an animal model of Attention-Deficit/Hyperactivity Disorder (ADHD)

BackgroundADHD is currently defined as a cognitive/behavioral developmental disorder where all clinical criteria are behavioral. Overactivity, impulsiveness, and inattentiveness are presently regarded as the main clinical symptoms. There is no biological marker, but there is considerable evidence to suggest that ADHD behavior is associated with poor dopaminergic and noradrenergic modulation of neuronal circuits that involve the frontal lobes. The best validated animal model of ADHD, the Spontaneously Hypertensive Rat (SHR), shows pronounced overactivity, impulsiveness, and deficient sustained attention. The primary objective of the present research was to investigate behavioral effects of a range of doses of chronic l-amphetamine on ADHD-like symptoms in the SHR.MethodsThe present study tested the behavioral effects of 0.75 and 2.2 mg l-amphetamine base/kg i.p. in male SHRs and their controls, the Wistar Kyoto rat (WKY). ADHD-like behavior was tested with a visual discrimination task measuring overactivity, impulsiveness and inattentiveness.ResultsThe striking impulsiveness, overactivity, and poorer sustained attention seen during baseline conditions in the SHR were improved by chronic treatment with l-amphetamine. The dose-response curves were, however, different for the different behaviors. Most significantly, the 0.75 mg/kg dose of l-amphetamine improved sustained attention without reducing overactivity and impulsiveness. The 2.2 mg/kg dose improved sustained attention as well as reduced SHR overactivity and impulsiveness.DiscussionThe effects of l-amphetamine to reduce the behavioral symptoms of ADHD in the SHR were maintained over the 14 days of daily dosing with no evidence of tolerance developing.

Acute and sub-chronic toxicity of a lyophilised aqueous extract of Centaurium erythraea in rodents

An aqueous concoction made from centaury (Centaurium erythraea (L.) Rafn., (Gentianaceae) whole plant is used in the Moroccan traditional medicine for the treatment of diabetes, as well as a number of other diseases. No systematic study of the potential toxicity of the plant has been described. The present investigation was carried out to evaluate the safety of an aqueous extract of Centaurium erythraea whole plant (CE-extract) by determining its potential toxicity after acute and sub-chronic administration in rats and mice. For the acute study, the lyophilised CE-extract was administered to adult IOPS OFA mice in single oral doses of 1-15 g/kg given by gavage, and single intraperitoneal (i.p.) doses of 1-14 g/kg. General behavioral adverse effects, mortality, and latency of mortality were determined for up to 14 days. In the sub-chronic dose study, the CE-extract was administered orally at doses of 100, 600 and 1200 mg/kg daily for 90 days to Wistar rats. Body weight and selected biochemical and hematological parameters were determined every 30 days and at the end of 90 days of daily administration; sections of liver and kidney were examined histologically for any signs of organ damage at the end of the treatment. In the acute study in mice, there were no deaths or any signs of toxicity observed after oral administration of single doses of the CE-extract at any dose level up to the highest dose tested (15 g/kg), which was the no-observed-adverse-effect level (NOAEL). However, the mortality rate as well as the acute toxicity of the i.p. administered CE-extract increased progressively with increasing dose. The NOAEL for the i.p. dose was 6 g/kg while the lowest-observed-adverse-effect level (LOAEL) was 8 g/kg; the calculated acute toxicity (LD(50)) of i.p. administered CE-extract in mice was 12.13 g/kg. In sub-chronic studies in rats, the CE-extract (administered orally at daily doses of 100, 600 and 1200 mg/kg for 90 days), did not cause any changes in hematological and biochemical parameters, except a small reduction of mean corpuscular volume, and a decrease in serum glucose and triglyceride levels at the higher doses. Histopathological examination of the liver and kidneys at the end of the study showed normal architecture suggesting no morphological disturbances. Because of the lack of toxicity of the CE-extract given by the oral route, and relatively high NOAEL values for the i.p. dose in the acute study in mice, as well as lack of mortality or clinically significant adverse changes in the biological and hematological parameters, and the morphology of liver and kidneys in rats after 90 days of daily dosing, it may be concluded that the CE-extract is relatively non-toxic. Also, in view of the doses consumed empirically in traditional medicine in Morocco, there is a wide margin of safety for the therapeutic use of Centaurium erythraea.

Effects of Chronic Introduction of Antidepressants on NMDA-Induced Damage to Neurons of the Rat Hippocampus and Cerebral Cortex

In in vitro studies on superfused slices obtained from the rat hippocampus and cortex, we found that 50 μM N-methyl-D-aspartate (NMDA) applied to the slices in the presence of 10 μM glycine for 15 min exerts a significant damaging action to neurons of these structures. One hour after termination of the action of NMDA, this was manifested in more than a twofold decrease in the synaptic reactivity of pyramidal neurons of the hippocampal СА1 area and layers II/III of the cerebral cortex. The excitotoxic effect of NMDA was prevented by application of competitive (D-2-amino-5-phosphonovaleric acid, 50 μM) and noncompetitive (ketamine, 100 μM) blockers of NMDA receptors. A blocker of glycine-binding sites of NMDA receptors (compound ТСВ 24.15, 10 μM) weakened NMDA-induced damage to the neurons. A competitive blocker of glutamate АМРА receptors, 6,7-dinitroquinoxaline-2,3-dione (DNQX, 10 μM), and a local anesthetic, lidocaine hydrochloride (50 μM), did not modify the excitotoxic effect of NMDA. A blocker of voltagedependent L-type calcium channels, verapamil (20 μM), demonstrated some trend to intensification of NMDA excitotoxic action. An inhibitor of tyrosine-protein phosphatases, sodium vanadate, when i.p. injected into rats in a dose of 15 mg/kg 6 h prior to the electrophysiological experiment, decreased the damaging action of NMDA. Two-hour-long treatment of cerebral slices with 1 μM genistein, an inhibitor of tyrosine kinases, weakened the neuroprotective effect of sodium vanadate. Chronic injections (14 days in daily doses of 20 mg/kg) of antidepressants belonging to different functional classes (imipramine, fluoxetine, and pyrazidol) into rats decreased (similarly to blockers of NMDA receptors) the excitotoxic action of NMDA receptors. Neuroprotective effects of antidepressants were weakened upon the action of genistein. We conclude that the neuroprotective activity of antidepressants under conditions of excitotoxic action of NMDA is mainly determined by an increase in the activity of tyrosine kinases in the cytoplasm and/or neuronal nucleus.

Effect of abomasal prebiotic supplementation on sheep faecal microbiota

The effect of abomasal fructo-oligosaccharides supplementation on sheep faecal microbiota was investigated in a balanced, two Latin square, cross-over design experiment. Ten fistulated sheep were managed in five consecutive periods, with each of five treatments (an ‘acidified saline’ control or one of four prebiotic candidates chosen to represent different types of oligosaccharides: Arabinogalactan, Fibruline, Raftilose, or Yacon) administered to two sheep in each period. Seven grams of fructo-oligosaccharides were used daily for each animal. In each period, fresh faecal samples were collected before, during and after ‘supplementation’ for the analysis of bifidobacteria, lactobacilli, Escherichia coli, sulphite-reducing clostridia, total anaerobes, pH and dry matter. The treatments with Fibruline, Raftilose and Yacon increased the sheep faecal bifidobacteria after 9 days of daily dosing. Compared with the control, the Raftilose treatment caused the greatest increase by 2.128 log10 CFU/g of faeces (P<0.01), followed by the Yacon and Fibruline treatments, by 0.990 (P<0.05) and 0.925 log10 CFU/g of faeces (P=0.05), respectively. Both Raftilose and Yacon treatments increased the number of lactobacilli by 1.286 (P<0.05) and 1.138 log10 CFU/g of faeces (P<0.05) after 9 days of daily dosing. All tested fructo-oligosaccharides had no effect on sulphite-reducing clostridia and E. coli. There were no changes in sheep faecal pH or dry matter between the treatments. These data provide the first evidence that the bifidogenic effects of fructo-oligosaccharides, previously shown to be gained in the large intestine of monogastric animals, are also efficacious in the ruminant.

Mechanism of subendocardial cell proliferation in the rat and relevance for understanding drug-induced valvular heart disease in humans

A number of drugs and drug candidates, including fenfluramine and ergot derivatives, are associated with valvulopathy in humans; however, these responses are poorly predicted from animal studies. In vitro and in vivo evidence suggests that these compounds exert their pathological effect through activation of serotonin 2B receptor (5HT2BR) signaling. However, the variable effect of fenfluramine and other 5HT2BR agonists in rodents has cast doubt on the relevance of animal findings to predicting human risk. Herein, a candidate compound, RO3013, induced subendocardial cell proliferation in the mitral and tricuspid valves in rats after only 3 days of daily dosing. Additionally, there was a treatment-related increase in immunostaining of the proliferation marker Ki67, and phosphorylated Smad3 in the heart indicative of TGFβ signaling co-localized with 5HT2BR expression. To substantiate the hypothesis that RO3013-induced valvular proliferation is secondary to 5HT2BR activation, the compound was evaluated in vitro and found to bind to the human 5HT2BR with a K i of 3.8 μM; however, it was virtually devoid of agonist activity in a functional assay in human cells. By contrast, RO3013 bound to the rat 5HT2BR with a K i of 1.2 μM and activated the receptor with an EC50 of 0.5 μM. This agonist potency estimate is in good agreement with the free plasma concentrations of RO3013 at which valvular proliferation was observed. These results suggest that the rat may be susceptible to 5HT2BR-mediated valvular proliferation similar to humans; yet, the significant differences between binding and functional activities can be a possible explanation for the observed species-selective receptor responses.

Ovarian LH/hCG receptors and plasma level of LH,17-beta estradiol and progesterone in gonadotropin--induced PCO syndrome in rats.

The aim of this work was to investigate the morphologic changes, LH/hCG receptor content in the ovaries and plasma levels of LH, progesterone and estradiol of hypo--and hyperthyroid rats injected with PMSG and hCG. The hypothyroid state was induced by thyreoidectomy (Tr-X) and the hyperthyroid condition by injections of 40 micrograms L-thyroxine daily during 21 days (T4). Gonadotropins were injected during 14 days in daily doses: PMSG--5 i.u. and hCG--10 i.u. The following 8 groups (n = 10-20) were established: control (euthyroid, no treatment), Tr-X, PMSG + hCG, Tr-X + hCG, Tr-X + PMSG, Tr-X + PMSG + hCG, T4 and T4 + PMSG. At the end of experiments rats were sacrificed, ovaries weighed, macroscopically inspected and concentration of LH/hCG receptors was estimated. In blood plasma the level of LH, progesterone and 17-beta estradiol was also analysed. The experiments showed that injections of PMSG alone, or PMSG + hCG in eu-or hypothyroid rats, appear the most effective in induction of PCO syndrome in rats. Low levels of thyroid hormones sensitized the ovaries to gonadotropin action, but a hyperthyroid status diminished or inhibited this response. Thyroid function is also essential in production of LH/hCG receptors in the ovaries. In hypothyroid animals the amount of these receptors was greatly increased, while in hyperthyroid animals they decreased. The level of plasma LH, progesterone, and estradiol showed insignificantly differences and various inconsiderable deviations from norm. These differences were not dependent on large doses of gonadotropins, altered thyroid function, or on cystic or luteinizing changes in the ovary.

Safety, Tolerability, and Pharmacokinetics of PA-824 in Healthy Subjects

PA-824 is a novel antibacterial agent that has shown in vitro activity against both drug-sensitive and drug-resistant Mycobacterium tuberculosis. The compound's MIC is between 0.015 and 0.25 microg/ml for drug-sensitive strains and between 0.03 and 0.53 microg/ml for drug-resistant strains. In addition, it is active against nonreplicating anaerobic Mycobacterium tuberculosis. The safety, tolerability, and pharmacokinetics of PA-824 were evaluated in two escalating-dose clinical studies, one a single-dose study and the other a multiple-dose study (up to 7 days of daily dosing). In 58 healthy subjects dosed with PA-824 in these studies, the drug candidate was well tolerated, with no significant or serious adverse events. In both studies, following oral administration PA-824 reached maximal plasma levels in 4 to 5 h independently of the dose. Maximal blood levels averaged approximately 3 microg/ml (1,500-mg dose) in the single-dose study and 3.8 microg/ml (600-mg dose) in the multiple-dose study. Steady state was achieved after 5 to 6 days of daily dosing, with an accumulation ratio of approximately 2. The elimination half-life averaged 16 to 20 h. Overall, PA-824 was well tolerated following oral doses once daily for up to 7 days, and pharmacokinetic parameters were consistent with a once-a-day regimen. The results of these studies, combined with the demonstrated activity of PA-824 against drug-sensitive and multidrug-resistant Mycobacterium tuberculosis, support the investigation of this novel compound for the treatment of tuberculosis.

Plant-Derived Polysaccharide Supplements Inhibit Dextran Sulfate Sodium-Induced Colitis in the Rat

Several plant-derived polysaccharides have been shown to have anti-inflammatory activity in animal models. Ambrotose complex and Advanced Ambrotose are dietary supplements that include aloe vera gel, arabinogalactan, fucoidan, and rice starch, all of which have shown such activity. This study was designed to evaluate these formulations against dextran sulfate sodium (DSS)-induced colitis in rats and to confirm their short-term safety after 14 days of daily dosing. Rats were dosed daily orally with vehicle, Ambrotose or Advanced Ambrotose. On day six groups of rats received tap water or 5% Dextran Sulfate sodium. Ambrotose and Advanced Ambrotose significantly lowered the disease scores and partially prevented the shortening of colon length. An increase in monocyte count was induced by dextran sulfate sodium and inhibited by Ambrotose and Advanced Ambrotose. There were no observable adverse effects after 14-day daily doses. The mechanism of action of the formulations against DSS-induced colitis may be related to its effect on monocyte count.

Aerosolized Phosphoinositide 3-Kinase γ/δ Inhibitor TG100-115 [3-[2,4-Diamino-6-(3-hydroxyphenyl)pteridin-7-yl]phenol] as a Therapeutic Candidate for Asthma and Chronic Obstructive Pulmonary Disease

Phosphatidylinositol 3-kinases (PI3Ks) are key elements in the signaling cascades that lie downstream of many cellular receptors. In particular, PI3K delta and gamma isoforms contribute to inflammatory cell recruitment and subsequent activation. For this reason, in a series of preclinical studies, we tested the potential of a recently developed small-molecule inhibitor of these two isoforms, TG100-115 [3-[2,4-diamino-6-(3-hydroxyphenyl)pteridin-7-yl]phenol], as a form of anti-inflammatory therapy for respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD). To determine pharmacokinetic profiles, aerosolized formulations of the drug were delivered to mice by a nose-only inhalation route, yielding high pulmonary TG100-115 levels with minimal systemic exposure. Safety assessments were favorable, with no clinical or histological changes noted after 21 days of daily dosing. In a murine asthma model, aerosolized TG100-115 markedly reduced the pulmonary eosinophilia and the concomitant interleukin-13 and mucin accumulation characteristic of this disease. As a functional benefit, interventional dosing schedules of this inhibitor also reduced airway hyper-responsiveness. To model the pulmonary neutrophilia characteristic of COPD, mice were exposed to either intranasal lipopolysaccharide or inhaled smoke. Aerosolized TG100-115 again inhibited these inflammatory patterns, most notably in the smoke model, where interventional therapy overcame the steroid-resistant nature of the pulmonary inflammation. In conclusion, aerosolized TG100-115 displays pharmacokinetic, safety, and biological activity profiles favorable for further development as a therapy for both asthma and COPD. Furthermore, these studies support the hypothesis that PI3K delta and gamma are suitable molecular targets for these diseases.

Acute and sub-chronic toxicity of an aqueous extract of the leaves of Herniaria glabra in rodents

Aim of the study The present investigation was carried out to evaluate the safety of an aqueous extract of Herniaria glabra (caryophyllaceae) (HG) plant by determining its potential toxicity after acute and sub-chronic administration in rodents. Materials and Methods For the acute study, a lyophilized aqueous extract of HG plant was administered to adult IOPS OFA mice in single doses of 5–14.5 g/kg given by gavage. General behavior adverse effects and mortality were determined for up to 14 days. In the sub-chronic dose study, the HG-extract was administered orally at doses of 1, 2 and 4 g/kg daily for 90 days to Wistar rats. Selected biochemical and hematological parameters were determined after 30 and 60 days, and then at the end of 90 days of daily administration. Results In the acute study in mice, the crude aqueous extract of HG plant caused dose-dependent general behavior adverse effects and mortality. The no-observed adverse effect levels (NOAEL) of the HG extract was 5 g/kg and the lowest-observed adverse effect levels (LOAEL) was 5.5 g/kg. Mortality increased with increasing doses: the calculated LD 50 was 8.50 + 0.42 g/kg in mice. In the sub-chronic study in rats, daily oral administration of the crude HG extract for up to 90 days resulted in a significant attenuation of the normal increase in the body weight. At the highest dose, the HG-extract caused a significant increase in erythrocytes, leukocytes (WBC), platelets, and eosinophils, but it had no effect on the differential WBC counts (lymphocytes, monocytes, neutrophils and basophils). Only at the highest dose, the HG-extract caused a significant increase in serum levels of the liver enzymes, alanine aminotransferase and aspartate aminotransferase, as well as serum creatinine, indicating toxic effect of the high dose of the extract on the liver and kidney. The organ toxicity was confirmed by histopathological examination, which showed centrolobular sinusoidal congestion, disruption of the central vein and hepatocellular necrosis in the liver, and interstitial and intraglomerular congestion, tubular atrophy, and inflammation in the kidney. This study also revealed the hypoglycemic activity of the HG-extract in normoglycemic rats. The suppression of the normal weight gain and the hypoglycemic action of HG-extract should be investigated further for possible therapeutic implications. Conclusions Because of the relatively high NOAEL values in the acute study in mice, and lack of mortality or clinically significant changes in the biological (except for hypoglycemia) and hematological parameters in rats after 90 days of daily dosing, it may be concluded that the HG extract does not appear to have significant toxicity (except at high doses). In view of the doses consumed empirically in traditional medicine in Morocco, there is a wide margin of safety for the therapeutic use of Herniaria glabra.

A Phase I Pharmacokinetic and Pharmacodynamic Study of TKI258, an Oral, Multitargeted Receptor Tyrosine Kinase Inhibitor in Patients with Advanced Solid Tumors

To determine the maximum tolerated dose (MTD) dose-limiting toxicity, and pharmacokinetic and pharmacodynamic profile of TKI258 (formerly CHIR-258). A phase I dose escalating trial in patients with advanced solid tumors was performed. Treatment was initially as single daily doses on an intermittent 7-day on/7-day off schedule. Following a protocol amendment, a second schedule comprised, during cycle 1, 7-day on/7-day off treatment followed by 14 days of continuous daily dosing; subsequent cycles comprised 28 days of daily dosing. Pharmacokinetics and evaluation of phosphorylated extracellular signal-regulated kinase (ERK) in peripheral blood mononuclear cells were done during the first 28 days of each schedule. Thirty-five patients were treated in four intermittent (25-100 mg/d) and three continuous (100-175 mg/d) dosing cohorts. Observed drug-related toxicities were nausea and vomiting, fatigue, headache, anorexia, and diarrhea. Dose-limiting toxicities were grade 3 hypertension in one patient at 100 mg continuous dosing, grade 3 anorexia in a second patient at 175 mg, and grade 3 alkaline phosphatase elevation in a third patient at 175 mg. One patient had a partial response (melanoma) and two patients had stable disease >6 months. TKI258 pharmacokinetics were linear over the dose range of 25 to 175 mg. Five of 14 evaluable patients had modulation of phosphorylated ERK levels. The MTD was defined as 125 mg/d. Evidence of antitumor activity in melanoma and gastrointestinal stromal tumors warrants further investigation, and other phase I studies are ongoing. Further pharmacodynamic evaluation is required in these studies to evaluate the biological effects of TKI258.

Acute and chronic toxicity of a lyophilised aqueous extract of Tanacetum vulgare leaves in rodents

Aim of the study The present investigation was carried out to evaluate the safety of an aqueous extract of tansy (Tanacetum vulgare L.) leaves by determining its potential toxicity after acute and chronic administration in rodents. Materials and Methods For the acute study, a lyophilized aqueous extract of tansy leaves was administered to mice in single doses of 0-13 g/kg given by gavage as well as intraperitoneal doses of 0–4.5 g/kg. General behavior adverse effects and mortality were determined for up to 14 days. In the chronic dose study, the extract was administered orally at doses of 0, 100, 300 and 600 mg/kg daily for 90 days to rats. Biochemical and hematological parameters were determined after 30 and 60 days, and then at the end of 90 days of daily administration. Results In the acute study in mice, the crude aqueous extract of tansy leaves caused dose-dependent general behavior adverse effects and mortality. The no-observed adverse effect levels (NOAEL) of the tansy extract were 7.0 g/kg and 1.0 g/kg, and the lowest-observed adverse effect levels (LOAEL) were 9.0 g/kg and 1.5 g/kg, when given by the oral and intraperitoneal routes, respectively. Mortality increased with increasing doses, with LD 50 of 9.9 g/kg and 2.8 g/kg for the oral and intraperitonal modes of administration, respectively. In the chronic study in rats, daily oral administration of the crude aqueous extract of tansy leaves for up to 90 days did not result in death or significant changes in the biological (except for hypoglycemia) and hematological parameters. Conclusions Because of the relatively high NOAEL values in the acute study in mice, and lack of significant effect on biological and hematological parameters in rats after 90 days of daily doses, the tansy extract does not appear to have significant toxicity. In view of the dose of tansy consumed in traditional medicine, there is a wide margin of safety for the therapeutic use of the aqueous extract of Tanacetum vulgare leaves.

Testicular functions and serum titers of LH and testosterone in methyl parathion-fed roseringed parakeets

Adult male roseringed parakeets were fed concentrations (0, 10 or 20 μg/100 g body wt./day) of methyl parathion (MP) for 5 or 10 days. There were four sampling periods for each treatment group. The first two sampling periods were after 5 or 10 days of daily dosing. In two other sampling periods, birds were given daily doses for 10 days, and sampling occurred at 5 or 10 days after the end of treatment. A significant dose- and duration-dependent reduction in the paired testicular weight, seminiferous tubular diameters, the number of tubules with healthy germ cells, plasma acetylcholinesterase (AChE) activity and plasma levels of luteinizing hormone (LH) and testosterone occurred in MP-fed birds. The inhibitory influences of MP persisted till day-5 and followed by recovery from the gonado-suppressive effects of MP at day-10 after the end of last treatment for 10 days. These findings provide the first experimental evidence that MP-induced testicular dysfunctions in parakeets possibly results from an impaired activity of hypophysial-gonadal axis. Moreover, it is evident that the organophosphorous (OP)-induced changes in the avian testes are reversible.

First in-human phase 1 trial of a novel amino-peptidase inhibitor, CHR-2797

3537 Background: CHR-2797 is a novel, orally bioavailable agent which displays potent, tumor cell-selective, anti-proliferative properties. It is an inhibitor of Zn++-dependent aminopeptidases and generates signs of amino acid deprivation in sensitive cells, decreased protein synthesis and an increase in the level of the pro-apoptotic protein, Noxa. CHR-79888 is an active metabolite of CHR-2797. Patients and Methods: This study was conducted according to an accelerated titration design to define the MTD, DLT, toxicity profile and PK of CHR-2797 when administered orally for 28 days or longer. Patients (ECOG PS = 2) with histologically confirmed advanced solid tumors resistant or refractory to standard therapy were eligible. Results: 37 pts (median age 61.5 years [range 22.4–80.1]; 30M/7F; median ECOG PS 1; median prior regimens 2, range 0–6) enrolled in 12 cohorts (doses between 10 and 320mg). The first four patients received a 10 mg dose for 7, 14, 21 or 28 days respectively. Subsequent cohorts received 28 days continuous dosing, with dose doubling in single patient cohorts until drug-related toxicity = Grade 2. Thereafter the study followed a 3+3 design with = 40% dose increments. Common (gr 1–2) toxicity included fatigue (47%), diarrhea (47%), dizziness (24%), constipation, vomiting, abdominal pain (all 21%), and thrombocytopenia (18%). Toxicities show dose dependency for thrombocytopenia and fatigue. MTD was declared at 320 mg after 2 DLT’s were reported: 2 patients were unable to complete 28 days of daily dosing due to syncope/anemia, and dizziness/visual disturbances/thrombocytopenia, respectively. Patients recovered fully after cessation of the drug. The dose level below (240 mg) was expanded to 13 patients. Plasma PK was determined for both CHR-2797 and -79888, on days 1 and 28, which showed dose proportional increases in AUC and Cmax. Intracellular and intratumoral levels of both the parent and metabolite were also measured. So far 4 patients continued therapy for 7–9 months: one patient (RCC [130 mg]) achieved a PR, and 3 patients (ovarian ca [40 mg], NSCLC [130 mg], and breast ca [180 mg] had confirmed SD (&gt; 3 months). Conclusion: Once daily oral CHR-2797 can be administered safely for 28 days in doses up to 240 mg and exhibits favorable PK. No significant financial relationships to disclose.

Chronic PYY3–36 treatment promotes fat oxidation and ameliorates insulin resistance in C57BL6 mice

PYY(3-36) is a gut-derived hormone acting on hypothalamic nuclei to inhibit food intake. We recently showed that PYY(3-36) acutely reinforces insulin action on glucose disposal in mice. We aimed to evaluate effects of PYY(3-36) on energy metabolism and the impact of chronic PYY(3-36) treatment on insulin sensitivity. Mice received a single injection of PYY(3-36) or were injected once daily for 7 days, and energy metabolism was subsequently measured in a metabolic cage. Furthermore, the effects of chronic PYY(3-36) administration (continuous and intermittent) on glucose turnover were determined during a hyperinsulinemic-euglycemic clamp. PYY(3-36) inhibited cumulative food intake for 30 min of refeeding after an overnight fast (0.29 +/- 0.04 vs. 0.56 +/- 0.12 g, P = 0.036) in an acute setting, but not after 7 days of daily dosing. Body weight, total energy expenditure, and physical activity were not affected by PYY(3-36). However, it significantly decreased the respiratory quotient. Both continuous and intermittent PYY(3-36) treatment significantly enhanced insulin-mediated whole body glucose disposal compared with vehicle treatment (81.2 +/- 6.2 vs. 77.1 +/- 5.2 vs. 63.4 +/- 5.5 micromol.min(-1).kg(-1), respectively). In particular, PYY(3-36) treatment increased glucose uptake in adipose tissue, whereas its impact on glucose disposal in muscle did not attain statistical significance. PYY(3-36) treatment shifts the balance of fuel use in favor of fatty acids and enhances insulin sensitivity in mice, where it particularly promotes insulin-mediated glucose disposal. Notably, these metabolic effects of PYY(3-36) remain unabated after chronic administration, in contrast to its anorexic effects.

Preclinical Efficacy of the Camptothecin-Polymer Conjugate IT-101 in Multiple Cancer Models

Preclinical efficacy of i.v. IT-101, a nanoparticulate conjugate of 20(S)-camptothecin and a cyclodextrin-based polymer, was investigated in several mouse xenografts. The effects of different multiple dosing schedules on tumor growth of LS174T colon carcinoma xenografts are elucidated. All multiple dosing schedules administered over 15 to 19 days resulted in enhanced efficacy compared with untreated or single-dose groups. Further improvements in antitumor efficacy were not observed when the dosing frequency was increased from three weekly doses to five doses at 4-day intervals or 5 days of daily dosing followed by 2 days without dosing repeated in three cycles using similar cumulative doses. This observation was attributed to the extended release characteristics of camptothecin from the polymer. Antitumor efficacy was further evaluated in mice bearing six different s.c. xenografts (LS174T and HT29 colorectal cancer, H1299 non-small-cell lung cancer, H69 small-cell lung cancer, Panc-1 pancreatic cancer, and MDA-MB-231 breast cancer) and one disseminated xenograft (TC71-luc Ewing's sarcoma). In all cases, a single treatment cycle of three weekly doses of IT-101 resulted in a significant antitumor effect. Complete tumor regression was observed in all animals bearing H1299 tumors and in the majority of animals with disseminated Ewing's sarcoma tumors. Importantly, IT-101 is effective in a number of tumors that are resistant to treatment with irinotecan (MDA-MB-231, Panc-1, and HT29), consistent with the hypothesis that polymeric drug conjugates may be able to overcome certain kinds of multidrug resistance. Taken together, these results indicate that IT-101 has good tolerability and antitumor activity against a wide range of tumors.