Urinary Pharmacokinetics Research Articles

An Extended Minimal Physiologically Based Pharmacokinetic Model: Evaluation of Type II Diabetes Mellitus and Diabetic Nephropathy on Human IgG Pharmacokinetics in Rats.

Although many studies have evaluated the effects of type 2 diabetes mellitus (T2DM) on the pharmacokinetics (PK) of low molecular weight molecules, there is limited information regarding effects on monoclonal antibodies. Our previous studies have reported significant increases in total (2-4 fold) and renal (100-300 fold) clearance of human IgG, an antibody isotype, in Zucker diabetic fatty (ZDF) rats. Pioglitazone treatment incompletely reversed the disease-related PK changes. The objective of this study was to construct a mechanistic model for simultaneous fitting plasma and urine data, to yield physiologically relevant PK parameters. We propose an extended minimal physiologically based PK (mPBPK) model specifically for IgG by classifying organs as either leaky or tight vascular tissues, and adding a kidney compartment. The model incorporates convection as the primary mechanism of IgG movement from plasma into tissues, interstitial fluid (ISF) in extravascular distribution space, and glomerular filtration rate (GFR), sieving coefficient and fraction reabsorbed in the kidney. The model captured the plasma and urine PK profiles well, and simulated concentrations in ISF. The model estimated a 2-4 fold increase in nonrenal clearance from plasma and 30-120 fold increase in renal clearance with T2DM, consistent with the experimental findings, and these differences in renal clearance were related to changes in GFR, sieving coefficient, and proximal tubular reabsorption. In conclusion, the mPBPK model offers a more relevant approach for analyzing plasma and urine IgG concentration-time data than conventional models and provides insight regarding alterations in distributional and elimination parameters occurring with T2DM.

An indirect evaluation of bone saturation with zoledronic acid after long-term Q4 week dosing using plasma and urine pharmacokinetics.

537 Background: Zoledronic acid (ZA) has a high binding affinity for human bone. This post-hoc analysis from the OPTIMIZE-2 trial evaluated whether there is evidence for bone saturation of ZA follo...

The Effect of Intravenous Sulfobutylether7-β-Cyclodextrin on the Pharmacokinetics of a Series of Adamantane-Containing Compounds

Intravenously administered (i.v.) drug-cyclodextrin (CD) inclusion complexes are generally expected to dissociate rapidly and completely, such that the i.v. pharmacokinetic profile of a drug is unchanged in the presence of CD. The altered pharmacokinetics of a synthetic ozonide in rats has been attributed to an unusually high-binding affinity (2.3 × 10(6) M(-1) ) between the drug and sulfobutylether7 -β-cyclodextrin (SBE7 -β-CD) with further studies suggesting a significant binding contribution from the adamantane ring. This work investigated the binding affinity of three adamantane derivatives [amantadine (AMA), memantine (MEM) and rimantadine (RIM)] to SBE7 -β-CD and the impact of complexation on their i.v. pharmacokinetics. In vitro studies defined the plasma protein binding, as well as the impact of SBE7 -β-CD on erythrocyte partitioning of each compound. SBE7 -β-CD binding constants for the compounds were within the typical range for drug-like molecules (10(2) -10(4) M(-1) ). The pharmacokinetics of AMA and MEM were unchanged; however, significant alteration of RIM plasma and urinary pharmacokinetics was observed when formulated with CD. In vitro studies suggested two factors contributing to the altered pharmacokinetics: (1) low plasma protein binding of RIM, and (2) decreased erythrocyte partitioning in the presence of high SBE7 -β-CD concentrations. This work demonstrated the potential for typical drug-cyclodextrin interactions to alter drug plasma pharmacokinetics.

A randomized, crossover study to investigate the pharmacokinetics and safety of inhaled fluticasone furoate and umeclidinium, administered separately and in combination via dry powder inhaler in healthy adult volunteers.

A combination of fluticasone furoate (FF) and umeclidinium (UMEC) has been considered for development for the treatment of asthma. The primary objectives were to investigate the plasma and urine pharmacokinetics (PK) of FF/UMEC in combination compared with FF and UMEC monotherapies. This randomized, double-blind, three-period crossover, single-center study in healthy volunteers assessed the PK of FF 400 mcg and UMEC 500 mcg administered separately and in combination (four inhalations of FF/UMEC 100/125 mcg, FF 100 mcg, or UMEC 125 mcg) via dual-strip dry powder inhaler. Subjects were randomized based on codes generated using a validated computerized system (Randall, GlaxoSmithKline). Eighteen subjects were enrolled; 17 received all three scheduled doses of study medication. Plasma FF and UMEC concentrations peaked at 0.5 and 0.08 h post-dose, respectively, for FF/UMEC and the monotherapies. FF and UMEC co-administration resulted in slightly lower or similar systemic exposure for both drugs versus the monotherapies. In post hoc sensitivity analyses (performed because two subjects administered inhalations incorrectly), the ratio of adjusted geometric means (maximum plasma concentration and area under the curve) was closer to unity than in the planned analyses. Cumulative urinary UMEC excretion (Ae) was similar for FF/UMEC and UMEC. Post hoc sensitivity analyses on Ae(0-24) suggested a small carryover effect but results were similar to those of the population as a whole. Urinary UMEC excretion following FF/UMEC was low (~1.5% over 24 h) and unlikely to have impacted upon PK comparisons. Three adverse events were reported; none were severe or led to withdrawal. There were no clinically significant effects on electrocardiogram, vital sign, or laboratory parameters. Fluticasone furoate and umeclidinium co-administration was well tolerated and was not associated with meaningful changes in systemic or urinary PK versus the monotherapies. GlaxoSmithKline.

Midazolam microdose to determine systemic and pre‐systemic metabolic CYP3A activity in humans

We aimed to establish a method to assess systemic and pre-systemic cytochrome P450 (CYP) 3A activity using ineffective microgram doses of midazolam. In an open, one sequence, crossover study, 16 healthy participants received intravenous and oral midazolam at microgram (0.001 mg intravenous and 0.003 mg oral) and regular milligram (1 mg intravenous and 3 mg oral) doses to assess the linearity of plasma and urine pharmacokinetics. Dose-normalized AUC and Cmax were 37.1 ng ml(-1 ) h [95% CI 35.5, 40.6] and 39.1 ng ml(-1) [95% CI 30.4, 50.2] for the microdose and 39.0 ng ml(-1 ) h [95% CI 36.1, 42.1] and 37.1 ng ml(-1) [95% CI 26.9, 51.3] for the milligram dose. CLmet was 253 ml min(-1) [95% CI 201, 318] vs. 278 ml min(-1) [95% CI 248, 311] for intravenous doses and 1880 ml min(-1) [95% CI 1590, 2230] vs. 2050 ml min(-1) [95% CI 1720, 2450] for oral doses. Oral bioavailability of a midazolam microdose was 23.4% [95% CI 20.0, 27.3] vs. 20.9% [95% CI 17.1, 25.5] after the regular dose. Hepatic and gut extraction ratios for microgram doses were 0.44 [95% CI 0.39, 0.49] and 0.53 [95% CI 0.45, 0.63] and compared well with those for milligram doses (0.43 [95% CI 0.37, 0.49] and 0.61 [95% CI 0.53, 0.70]). The pharmacokinetics of an intravenous midazolam microdose is linear to the applied regular doses and can be used to assess safely systemic CYP3A activity and, in combination with oral microdoses, pre-systemic CYP3A activity.

Novel alkylresorcinol metabolites in human urine as potential exposure biomarkers for whole grain wheat and rye intake (270.6)

Biomarkers of dietary intake are prominent tools in nutritional research. Alkylresorcinol (AR) metabolites, 3,5‐dihydroxybenzoic acid (3,5‐DHBA) and 3‐(3,5‐dihydroxyphenyl)propanoic acid (3,5‐DHPPA), have been proposed as exposure biomarkers of whole grain (WG) wheat and rye intake. However, the profile of AR metabolites is not fully understood. The aim of this study was to investigate the metabolism of ARs in mice and in humans, while further determining urinary pharmacokinetics of the novel AR metabolites to explore their potential as biomarkers of WG wheat intake. Utilization of LC‐MS approach resulted in ten AR metabolites (1‐10) identified in mice and in humans, including three phenolic acids and seven of their phase II conjugates. Among them, two novel metabolites were discovered, 5‐(3,5‐dihydroxyphenyl)pentanoic acid (3,5‐DHPPTA) and 2‐(3,5‐dihydroxybenzamido)acetic acid (3,5‐DHBA glycine). The structures of these two metabolites were confirmed by comparing with authentic standards synthesized in house. In the pharmacokinetic study, a group of twelve volunteers followed a polyphenolic restricted diet for 4 d before ingesting WG wheat bread containing 61mg ARs. Urine samples were collected for 32 h, and AR metabolites were quantified with HPLC‐CEAD. The mean urinary excretion rates and mean t1/2 of 3,5‐DHPPTA, 3,5‐DHBA glycine, 3,5‐DHBA and 3,5‐DHPPA at each time point were determined. Our results suggest that 3,5‐DHPPTA and 3,5‐DHBA glycine may be utilized in combination with 3,5‐DHBA and 3,5‐DHPPA as potential biomarkers to increase the accuracy of recording WG wheat and rye intake in epidemiologic studies. Further validation of 3,5‐DHPPTA and 3,5‐DHBA glycine as potential biomarkers is warranted.Grant Funding Source: 1This work was partially supported by funding from USDA‐NIFA grant 2012‐38821‐20012 to S. Sang.

Phase I Study of Oral Rigosertib (ON 01910.Na), a Dual Inhibitor of the PI3K and Plk1 Pathways, in Adult Patients with Advanced Solid Malignancies

To determine the pharmacokinetics (PK), maximum tolerated dose (MTD), safety, and antitumor activity of an oral formulation of rigosertib, a dual phosphoinositide 3-kinase (PI3K) and polo-like kinase 1 (Plk1) pathway inhibitor, in patients with advanced solid malignancies. Patients with advanced solid malignancies received rigosertib twice daily continuously in 21-day cycles. Doses were escalated until intolerable grade ≥2 toxicities, at which point the previous dose level was expanded to define the MTD. All patients were assessed for safety, PK, and response. Urinary PK were performed at the MTD. Archival tumors were assessed for potential molecular biomarkers with multiplex mutation testing. A subset of squamous cell carcinomas (SCC) underwent exome sequencing. Forty-eight patients received a median of 2 cycles of therapy at 5 dose levels. Rigosertib exposure increased with escalating doses. Dose-limiting toxicities were hematuria and dysuria. The most common grade ≥2 drug-related toxicities involved urothelial irritation. The MTD is 560 mg twice daily. Activity was seen in head and neck SCCs (1 complete response, 1 partial response) and stable disease for ≥12 weeks was observed in 8 additional patients. Tumors experiencing ≥partial response had PI3K pathway activation, inactivated p53, and unique variants in ROBO3 and FAT1, two genes interacting with the Wnt/β-catenin pathway. The recommended phase II dose of oral rigosertib is 560 mg twice daily given continuously. Urinary toxicity is the dose-limiting and most common toxicity. Alterations in PI3K, p53, and Wnt/β-catenin pathway signaling should be investigated as potential biomarkers of response in future trials.

Pharmacodynamic, pharmacokinetic and tolerability evaluation of concomitant administration of lesinurad and febuxostat in gout patients with hyperuricaemia

The aim of this study was to evaluate the pharmacodynamics (PDs), pharmacokinetics (PKs) and safety of lesinurad (selective uric acid reabsorption inhibitor) in combination with febuxostat (xanthine oxidase inhibitor) in patients with gout. This study was a phase IB, multicentre, open-label, multiple-dose study of gout patients with serum uric acid (sUA) >8 mg/dl following washout of urate-lowering therapy with colchicine flare prophylaxis. Febuxostat 40 or 80 mg/day was administered on days 1-21, lesinurad 400 mg/day was added on days 8-14 and then lesinurad was increased to 600 mg/day on days 15-21. sUA, urine uric acid and PK profiles were evaluated at the end of each week. Safety was assessed by adverse events, laboratory tests and physical examinations. Initial treatment with febuxostat 40 or 80 mg/day monotherapy resulted in 67% and 56% of subjects, respectively, achieving a sUA level <6 mg/dl. Febuxostat 40 or 80 mg/day plus lesinurad 400 or 600 mg/day resulted in 100% of subjects achieving sUA <6 mg/dl and up to 100% achieving sUA <5 mg/dl. No clinically relevant changes in the PKs of either drug were noted. The combination was well tolerated. The clinically important targets of sUA <6 mg/dl and <5 mg/dl are achievable in 100% of patients when combining lesinurad and febuxostat.

Identification and Pharmacokinetics of Novel Alkylresorcinol Metabolites in Human Urine, New Candidate Biomarkers for Whole-Grain Wheat and Rye Intake1–3

Biomarkers of dietary intake are prominent tools in nutritional research. The alkylresorcinol metabolites 3,5-dihydroxybenzoic acid (3,5-DHBA) and 3-(3,5-dihydroxyphenyl)propanoic acid (3,5-DHPPA) have been proposed as exposure biomarkers of whole-grain (WG) wheat and rye intake. However, the profile of alkylresorcinol metabolites is not fully understood. The aim of this study was to investigate the metabolism of alkylresorcinols in mice and in humans, while further determining urinary pharmacokinetics of the novel alkylresorcinol metabolites to explore their potential as biomarkers of WG wheat intake. Utilization of the liquid chromatography–mass spectrometry approach resulted in 10 alkylresorcinol metabolites identified in mice and in humans, including 3 phenolic acids and 7 of their phase II conjugates. Among them, 2 novel metabolites were discovered: 5-(3,5-dihydroxyphenyl)pentanoic acid (3,5-DHPPTA) and 2-(3,5-dihydroxybenzamido)acetic acid (3,5-DHBA glycine). The structures of these 2 metabolites were confirmed by comparing with authentic standards synthesized in-house. In the pharmacokinetic study, a group of 12 volunteers consumed a polyphenolic-restricted diet for 4 d before ingesting WG wheat bread containing 61 mg of alkylresorcinols. Urine samples were collected for 32 h, and alkylresorcinol metabolites were quantified with HPLC–coulometric electrode array detection. The mean urinary excretion rates and mean apparent half-life of 3,5-DHPPTA, 3,5-DHBA glycine, 3,5-DHBA, and 3,5-DHPPA at each time point were determined. Our results suggest that 3,5-DHPPTA and 3,5-DHBA glycine may be used in combination with 3,5-DHBA and 3,5-DHPPA as potential biomarkers to increase the accuracy of recording WG wheat and rye intake in epidemiologic studies. Further validation of 3,5-DHPPTA and 3,5-DHBA glycine as potential biomarkers is warranted.

Effect of moderate liver impairment on the pharmacokinetics of opicapone

Opicapone (OPC) is a novel catechol-O-methyltransferase (COMT) inhibitor to be used as adjunctive therapy in levodopa-treated patients with Parkinson's disease. The purpose of this study was to evaluate the effect of moderate liver impairment on the pharmacokinetics (PK) and pharmacodynamics (PD; effect on COMT activity) of OPC. An open-label, parallel-group study in patients (n = 8) with moderate liver impairment (Child-Pugh category B, score of 7 to 9) and matched healthy subjects (n = 8, control) with normal liver function. All subjects received a single 50-mg oral dose of OPC, with plasma and urine concentrations of opicapone and its metabolites measured up to 72h post-dose, including soluble COMT (S-COMT) activity. A one-way analysis of variance (ANOVA) was used to compare the main PK and PD parameters between groups. Point estimates (PE) of geometric mean ratios (GMR) and corresponding 90% confidence intervals (90%CI) for the ratio hepatic/control subjects of each parameter were calculated and compared with the reference interval (80-125%). Exposure to opicapone (AUC and Cmax) increased significantly in patients with moderate hepatic impairment (PE [90%CI]: AUC0-∞, 184% [135-250%]; Cmax, 189% [144-249%]). Although apparent total clearance (CL/F) of opicapone was decreased by ∼35%, similar elimination half-life and unbound/bound fractions of opicapone were observed between the two groups. Both rate and extent of exposure to BIA 9-1103 were higher in the hepatically impaired group, but not statistically significant compared with the control group. Similar to the parent (opicapone), the observed increase in exposure to BIA 9-1106 was statistically significant in the hepatically impaired group over the control group. BIA 9-1106 was the only metabolite detected in urine and its urine PK parameters were in accordance with plasma data. Maximum S-COMT inhibition (Emax) occurred earlier for the hepatically impaired group with values of 100% and 91.2% for the hepatically impaired and control groups respectively. Both Emax and AUEC for the hepatically impaired group reached statistical significance over the control group. OPC was well tolerated in both hepatically impaired and control groups. The bioavailability of an orally administered single dose of 50mg OPC was significantly higher in patients with moderate chronic hepatic impairment, perhaps by a reduced first-pass effect. As the tolerability profile of OPC was favourable under the conditions of this study and its exposure is completely purged from systemic circulation before the subsequent dose administration, no OPC dose adjustment is needed in patients with mild to moderate chronic hepatic impairment. However, as OPC is under clinical development for use as adjunctive therapy in levodopa-treated patients with Parkinson's disease, an adjustment of levodopa and/or OPC regimens in patients should be carefully considered based on a potentially enhanced levodopa dopaminergic response and the associated tolerability.

Safety, Tolerability and Pharmacokinetics and Pharmacodynamics of Inhaled Once-Daily Umeclidinium in Healthy Adults Deficient in CYP2D6 Activity: A Double-Blind, Randomized Clinical Trial

Umeclidinium is a new, long-acting, muscarinic receptor antagonist currently in development for the treatment of chronic obstructive pulmonary disease (COPD). In vitro cell culture data suggest that up to 99 % of umeclidinium is potentially metabolized by cytochrome P450 2D6 (CYP2D6), but without a definitive human metabolism radiolabel study, the extrapolation of in vitro to in vivo is only an estimate. The objective of this study was to investigate the safety, tolerability, pharmacokinetics and pharmacodynamics of umeclidinium in patients with normal and deficient CYP2D6 metabolism. This was a randomized, placebo-controlled study to assess the safety, tolerability, pharmacokinetics and pharmacodynamics of inhaled single and repeat doses (for 7 days) of umeclidinium. The study took place at a single clinical site, at which subjects remained throughout the study. Healthy volunteers (HVTs) who were normal CYP2D6 metabolizers (HVT-NMs) [n = 20] and poor CYP2D6 metabolizers (HVT-PMs) [n = 16] participated in the study. The subjects received umeclidinium (100-1,000 μg) and placebo as single and repeat doses. The primary outcome measurements were protocol-defined safety and tolerability endpoints. Thirteen subjects in each population reported adverse events (AEs); none were considered serious. No clinically significant abnormalities in vital signs, lung function, haematology, biochemistry, 12-lead electrocardiograms (ECGs) or 24-h Holter ECGs were attributable to the study drug. There were no differences in plasma and urine pharmacokinetics between populations: the plasma area under the concentration-time curve over the dosing interval (from 0 to 24 h for the once-daily drug) [AUC(τ) (ng·h/mL)] and the maximum plasma concentration [C(max) (ng/mL)] ratios (with 90 % confidence intervals [CIs]) following repeat dosing with 500 μg umeclidinium for HVT-PMs (as compared with HVT-NMs) were 1.03 (0.79-1.34) and 0.80 (0.59-1.08), respectively; the cumulative amount of the unchanged drug excreted into the urine at 24 h (Ae(24)) [ng] ratio was 1.01 (0.82-1.26). Following repeat dosing with umeclidinium 1,000 μg, the plasma AUC(τ) [ng·h/mL] and C(max) (ng/mL) ratios (with 90 % CIs) were 1.33 (0.98-1.81) and 1.07 (0.76-1.51); the urine Ae(24) (ng) ratio was 1.47 (1.15-1.88). Similar ratios for urine and plasma were observed following single and repeat-dose regimens. Umeclidinium has favourable safety and pharmacokinetic profiles in both HVT-NM and HVT-PM populations.

Serum and urine pharmacokinetics of tigecycline in obese class III and normal weight adults

To compare the serum and urine pharmacokinetics (PK) of intravenous tigecycline in obese class III (obese-C3) adults with those in normal weight (NW) adults. Obese-C3 (n = 8) and NW (n = 4) healthy adult volunteers received a single intravenous dose of 100 mg of tigecycline for 30 min. Serum (0-96 h) and urine (0-48 h) tigecycline concentrations were assayed by liquid chromatography with tandem mass spectrometry. Parametric population PK systems analyses were used to model the data and assess the effects of total body weight (TBW) on PK parameters. The area under the concentration-time curve extrapolated to infinity (AUC0-∞) was simulated to estimate the probability of AUC0-∞ : MIC target attainment and cumulative fraction of response (CFR) based on wild-type MIC distributions of select pathogens. Clinicaltrials.gov: NCT01560143. The median (range) age, TBW and initial body mass index were 42 (20-50) years, 121 (61-160) kg and 43.8 (20.8-53.8) kg/m(2), respectively. The serum concentration-time profiles and exposures were similar in the obese-C3 and NW adults, with a mean urine recovery of 15.8% and 13.4%, respectively. The median (range) AUC0-∞ was 8.19 (6.12, 11.2) and 7.50 (6.78, 9.13) mg · h/L in the obese-C3 and NW groups, respectively. The clearance of tigecycline was not related to TBW. The CFR was calculated to be <90% against Acinetobacter baumannii, Enterobacter cloacae and Klebsiella pneumoniae for an AUC0-∞ : MIC target ≥ 6.96. The serum and urine PK of tigecycline is similar in obese-C3 and NW healthy adults. A lower CFR is predicted against certain Gram-negative pathogens with the current standard tigecycline dosing regimen, irrespective of TBW.

Darexaban (YM150), an oral direct factor Xa inhibitor, has no effect on the pharmacokinetics of digoxin

To investigate the impact of the direct Factor Xa inhibitor darexaban administered in a modified-release formulation (darexaban-MR) on the pharmacokinetic (PK) profile of digoxin. In this Phase I, randomized, double-blind, two-period crossover study (8 days for each treatment, 10 days washout), 24 healthy subjects received darexaban-MR 120 mg once/day (qd) + digoxin 0.25 mg qd in one treatment period, and placebo + digoxin 0.25 mg qd in the other treatment period. Blood for PK assessment of digoxin and darexaban was obtained in serial profile on day 8, as well as pre-dose on day 6-7; urinary PK samples were obtained up to 24 h after the last dose on day 8. A lack of interaction was determined if 90 % confidence intervals (CIs) for the geometric mean ratios (GMR) of digoxin C max,ss and AUC0-24h,ss with and without darexaban-MR co-administration were within 0.80-1.25 limits. Pharmacodynamic activity was assessed by international normalized ratio and activated partial thromboplastin time. Twenty-three subjects completed the study. The GMR (90 % CI) for C max,ss and AUC0-24h,ss of digoxin plus darexaban versus digoxin plus placebo was 1.03 (90 % CI: 0.94-1.12) and 1.11 (90 % CI: 1.05-1.17), respectively. The 90 % CI for the GMRs fell within the limits of 0.80-1.25, indicating a lack of drug-drug interaction. Co-administration of digoxin with darexaban-MR was well tolerated, with no unexpected treatment-emergent adverse events or safety concerns. Co-administration of darexaban-MR did not impact the steady-state PK profile of digoxin.

Overall clinical evaluation of panipenem/betamipron against infections in pediatric field

To conduct a basic-clinical study on newly developed panipenem/betamipron (CS-533/CS-443, PAPM/BP) against various infections in pediatrics, a study group was organized and a joint research by 17 institutions and their related hospitals was undertaken. The obtained results are as follows. 1. Blood concentrations and urinary excretion Pharmacokinetics of PAPM/BP in children was studied using 30 minutes intravenous drip infusion of 10 mg/10 mg/kg, 20 mg/20 mg/kg and 30 mg/30 mg/kg, respectively. Maximum blood levels of PAPM/BP were observed at the completion of drip infusion and were 26.72 +/- 8.78 micrograms/ml/18.33 +/- 8.54 micrograms/ml (mean +/- S.D.) with administration of 10 mg/10 mg, 64.80 +/- 18.50 micrograms/ml/38.74 +/- 16.41 micrograms/ml with administration of 20 mg/20 mg and 91.70 +/- 29.42 micrograms/ml/50.08 +/- 22.41 micrograms/ml with administration of 30 mg/30 mg. Dose dependency was noted with these doses. The half-life was about 1 hour for PAPM and about 0.5 hour for BP. As for urinary excretion, PAPM was excreted about 30% and BP about 70% in the first 6 hours after the start of drip infusion. 2. Clinical results Twenty-five cases of exclusion and drop-out were deducted from a total of 391 cases and 8 cases having 2 diseases concurrently were added to the remaining 366 cases, hence 374 cases were evaluated in the study as the subjects of analysis of clinical effects. As for clinical effects in cases where pathogenic bacteria were detected, 215 out of 221 cases were rated as effective or above, hence the efficacy rate of 97.3% was obtained. In cases where pathogenic bacteria were not detected, 145 out of 153 cases were rated as effective or above, thus the efficacy rate was 94.8% which is similar to that in the cases where pathogenic bacteria were detected. The daily dose levels most commonly employed were 30 to 60 mg/kg (as PAPM) administered in 3 divided doses a day, and this regimen method accounted for 52.7% of the total cases, and the efficacy rate with this regimen was 97.0%. As for the bacteriological effect 87 (96.7%) out of 90 strains of Gram-positive bacteria (GPB) disappeared and 136 (91.3%) out of 149 strains of Gram-negative bacteria (GNB) disappeared upon the treatment. The overall bacterial eradication rate for the pathogenic bacteria was 93.4%.(ABSTRACT TRUNCATED AT 400 WORDS)

Abstract LB-198: Phase I and molecular correlates study of oral rigosertib in patients with refractory metastatic head and neck cancer and advanced solid tumors.

Abstract Background: Rigosertib (ON 01910.Na) is a novel inhibitor of several kinases, including polo-like kinase 1 and PI-3 kinase, in advanced trials for myelodysplastic syndrome and pancreatic cancer as an IV agent. An oral formulation with good bioavailability was developed and tested in a phase I clinical evaluation in patients with advanced solid tumors. The goals of this study were to determine the dose limiting toxicities, recommended phase II dose, pharmacokinetic (PK) profiles, to document any antitumor activity, and to conduct exome sequencing in selected cohorts. Methods: Patients (pts) with histologically confirmed solid tumors refractory to standard therapy were given escalating doses of rigosertib (70, 140, 280, 560, 700 mg) twice daily continuously. Doses were escalated until intolerable grade 2 or grade 3/4 toxicities were achieved, at which point the previous dose level was expanded to define the MTD. All pts were assessed for safety, PK, PD and response. At the MTD. Urinary PK assessments were performed at the MTD. Results: Forty eight pts were treated at 5 dose levels: (70mg n=3; 140mg n=2; 280mg n=3; 560mg n=33; 700mg n=7). The dose limiting toxicity (DLT) was dysuria at 700 mg and led to expansion at 560mg bid. The drug was well tolerated, the primary toxicity being urinary. Grade 2/3 urinary toxicities related to rigosertib at the 560mg recommended phase II dose included dysuria (12/2), cystitis (3/0), hematuria (0/1), urinary frequency/urgency (1/0), urinary hesitancy (1/0), bladder irritation (1/0). Improvements in dysuria were seen with oral hydration and sodium bicarbonate. Two metastatic head and neck squamous cell carcinoma patients refractory to platinum-based therapy had confirmed CR (disappearance of mediastinal and lung disease) and PR (53% decrease of liver metastasis), and have been 98+ and 48+ weeks on study. These patients had pre-treatment PIK3CA copy gain and PTEN loss, respectively. In addition, SD was observed in 2 pts with ovarian cancer (56 weeks, 28 weeks), and 1 pt each with pancreatic neuroendocrine (40 weeks), carcinoid (32 weeks), nasopharyngeal (24 weeks) and renal cell (37 weeks) tumors. A patient with SCC of the cervix developed hemoperitoneum suspected to be related to tumor necrosis, and also had PIK3CA copy gain. Exome sequencing of the entire cohort of HNSCC and SCC has been conducted. Preliminary PK data reveals plasma rigosertib levels above the predicted pharmacodynamically active levels. Conclusions: Here we present final results of the phase I study or daily rigosertib given orally BID, and molecular correlates in a cohort reflective of the efficacy signal. Based on these dramatic responses to rigosertib in two patients with metastatic HNSCC refractory to platinum-based therapy, a phase II trial is underway in this patient population. Whole exome sequencing analyses from archival tissue will be presented at the meeting. Citation Format: Antonio Jimeno, Daniel Bowles, Dara Aisner, Jennifer Diamond, Elaine Lam, Colin Weekes, Stephen Leong, Lia Gore, Elizabeth Freas, Gail Eckhardt, Wells Messersmith, Marileila Garcia-Varella, Francois Wilhelm. Phase I and molecular correlates study of oral rigosertib in patients with refractory metastatic head and neck cancer and advanced solid tumors. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-198. doi:10.1158/1538-7445.AM2013-LB-198

Impact of low-level fluoroquinolone resistance genes qnrA1, qnrB19 and qnrS1 on ciprofloxacin treatment of isogenic Escherichia coli strains in a murine urinary tract infection model

To study the impact of qnrA1, qnrB19 and qnrS1 on the ciprofloxacin treatment of urinary tract infection (UTI). From a wild-type (wt) Escherichia coli UTI isolate, three isogenic strains were constructed carrying low-level ciprofloxacin resistance genes qnrA1, qnrB19 or qnrS1 (ciprofloxacin MIC range: 0.19-0.38 mg/L). Time-kill studies were performed for all four isogenic strains at the following concentrations: 1×, 2×, 4×, 8× and 16× MIC. Ciprofloxacin serum and urine pharmacokinetics was determined to calculate a murine dose equivalent (AUC(24)) to the standard human dose of 500 mg twice daily, which corresponded to 0.2 mg/mouse four times daily. In the murine UTI model, mice infected with each of the isogenic qnr strains or the wt strain were treated with ciprofloxacin (0.2 mg/mouse) or saline (only the E. coli wt) subcutaneously four times daily for 3 days starting 24 h after bacterial inoculation. In vitro, the strains responded to ciprofloxacin concentrations of 4-16× MIC by several log(10) reductions. In vivo, despite ciprofloxacin reaching urine concentrations far exceeding the MICs for the strains (500 mg/L), ciprofloxacin was significantly less efficient at reducing the urine and bladder bacterial counts of qnrA1-, qnrB19- and qnrS1-positive strains compared with the ciprofloxacin-treated wt strain (P < 0.05). None of the four strains infected the kidneys well, with median cfu counts of <1 log(10). Although qnr genes only confer low levels of resistance to ciprofloxacin, a reduced bactericidal activity of ciprofloxacin was observed in both urine and bladder in the murine model of UTI.

Phase I study of oral rigosertib in patients with advanced solid tumors.

3017 Background: Rigosertib (ON 01910.Na) is a new multi-targeted inhibitor of several kinases, including polo-like kinase 1 and PI-3 kinase, and is in advanced trials for myelodysplastic syndrome and pancreatic cancer as an IV agent. An oral formulation with good oral bioavailability has entered phase 1 in patients (pts) with advanced solid tumors to determine the dose limiting toxicities (DLT), recommended phase II dose, pharmacokinetic (PK) profiles, and to document any antitumor activity of this compound. Methods: Pts with histologically confirmed solid tumors refractory to standard therapy were given escalating doses of rigosertib (70, 140, 280, 560, 700 mg) twice daily continuously. Doses were escalated until intolerable grade 2 or grade 3/4 toxicities, at which point the previous dose level was expanded to define the MTD. All pts were assessed for safety, PK, PD and response. Urinary PK assessments were also performed at the MTD. Results: 25 pts (median age= 59; median ECOG PS= 1) received a median of 6 weeks of therapy at 5 dose levels: (70 mg n=3; 140 mg n=2 ; 280 mg n=3; 560 mg n=10; 700 mg n=7). The DLT was dysuria at 700 mg and led to expansion at 560 mg bid. There were no DLTs in the expansion cohort. Grade 2/3 toxicities related to rigosertib included dysuria (5/1), cystitis (4/0), urinary frequency (3/0), hematuria (2/1), abdominal pain (2/0), pelvic pain (1/1), nausea (1/0), distention/bloating (1/0) and hyponatremia (0/1). Improvements in dysuria were seen with oral hydration and sodium bicarbonate. A confirmed PR occurred in 1 pt (HN squamous cell ca, 42+ weeks), and SD was observed in 2 pts with ovarian cancer (56 weeks, 28 weeks), and 1 pt each with pancreatic neuroendocrine (40 weeks), carcinoid (32 weeks), nasopharyngeal (24 weeks) and renal cell (32+ weeks) tumors. Preliminary PK data reveal plasma rigosertib levels above the predicted pharmacodynamically active levels. Conclusions: The MTD of oral rigosertib administered twice daily continuously is 560mg. Dysuria is the dose limiting and most common toxicity and can be managed with oral hydration and sodium bicarbonate. Antitumor activity has been observed. Final safety and efficacy results, plasma and urinary PK relationships, and mutational analyses from archival tissue will be presented.

Abstract 67: Phase I Safety, Pharmacokinetic, and Pharmacodynamic Results for ALN-PCS, a Novel RNAi Therapeutic for the Treatment of Hypercholesterolemia

Proprotein convertases subtilisin/kexin type 9 (PCSK9) is a member of the proprotein convertase (PC) family of subtilisin-like serine endoproteases that regulates low density lipoprotein receptor (LDLR) levels and function. Murine models and human genetic studies indicate that loss of PCSK9 protein increases LDLR levels while excess PCSK9 decreases LDLR levels. These changes in LDLR protein levels coincide with reciprocal changes in circulating levels of plasma LDL cholesterol (LDL-C). We have developed a highly potent RNA interference (RNAi) therapeutic, ALN-PCS, targeting both intra and extracellular PCSK9 for inhibition through an RNAi mechanism. Pre-clinical data in non-human primate models, indicate that a single intravenous dose of ALN-PCS results in rapid, dose dependent, and significant lowering of liver PCSK9 transcript, plasma PCSK9 protein and subsequently serum LDL-C and ApoB levels, without impacting serum HDL-C. Here we report on interim data from an ongoing Phase 1 trial of ALN-PCS being conducted as a randomized, single-blind, placebo-controlled, single-ascending dose study in healthy volunteer subjects with elevated baseline LDL-C (&gt;116mg/dL) who are not on any lipid lowering therapy. The primary objective of the study is to evaluate the safety and tolerability of a single dose of ALN-PCS, with subjects being enrolled into sequential cohorts of increasing doses. Secondary objectives of the study include characterization of plasma and urine pharmacokinetics of ALN-PCS, assessment of pharmacodynamic effects of the drug on plasma PCSK9 protein levels, and evaluation of clinical efficacy as measured by LDL-C levels. Data from 20 subjects enrolled in five sequential dose cohorts ranging from 0.015 to 0.250 mg/kg in a 3:1 randomization of drug to placebo will be presented. ALN-PCS was safe and well tolerated in this study and there have been no serious adverse events related to study drug administration to date. There have been no drug-related discontinuations from the study and no liver enzyme elevations. A mild, transient rash that resolved spontaneously was observed in three subjects that received ALN-PCS, and in two that received placebo. To date, administration of ALN-PCS resulted in a rapid, dose-dependent, and durable silencing of PCSK9 protein levels in plasma of up to 66% relative to baseline, with a statistically significant mean reduction of 60% at day four in the current high dose group of 0.250 mg/kg (p&lt;0.001). In addition, administration of ALN-PCS resulted in dose-dependent reductions in LDL-C of up to 50% relative to baseline, with a statistically significant mean reduction of 39% at day four (p&lt;0.05) at the 0.250 mg/kg dose level. There was no significant decrease in high-density lipoprotein (HDL). Dosing of further cohorts at the current top dose (0.25 mg/kg) and at a higher dose is planned. Additional data will be presented as available.

Modulation of pharmacokinetics of theophylline by antofloxacin, a novel 8-amino-fluoroquinolone, in humans

To evaluate the pharmacokinetic interactions between theophylline and antofloxacin in vivo and in vitro. A randomized, 5-day treatment and 3-way crossover design was documented in 12 healthy subjects. The subjects were orally administered with antofloxacin (400 mg on d 1 and 200 mg on d 2 to 5), theophylline (100 mg twice a day and morning dose 200 mg on d 1 and 5), or theophylline plus antofloxacin. The plasma and urinary pharmacokinetics of antofloxacin and theophylline were characterized after the first and last dose. The effect of antofloxacin on theophylline metabolism was also investigated in pooled human liver microsomes. The 5-day treatment with antofloxacin significantly increased the area of the plasma concentration-time curve and peak plasma concentration of theophylline, accompanied by a decrease in the excretion of theophylline metabolites. On the contrary, theophylline did not affect the pharmacokinetics of antofloxacin. In vitro studies using pooled human hepatic microsomes demonstrated that antofloxacin was a weak reversible and mechanism-based inhibitor of CYP1A2. The clinical interaction between theophylline and antofloxacin was further validated by the in vitro results. The results showed that antofloxacin increases the plasma theophylline concentration, partly by acting as a mechanism-based inhibitor of CYP1A2.

Twenty-Four Hour Human Urine and Serum Profiles of Bisphenol A during High-Dietary Exposure

By virtue of its binding to steroid hormone receptors, bisphenol A (BPA, the unconjugated bioactive monomer) is hypothesized to be estrogenic when present in sufficient quantities in the body, raising concerns that widespread exposure to BPA may impact human health. To better understand the internal exposure of adult humans to BPA and the relationship between the serum and urinary pharmacokinetics of BPA, a clinical exposure study was conducted. Blood and urine samples were collected approximately hourly over a 24-h period from 20 adult volunteers who ingested 100% of one of three specified meals comprising standard grocery store food items for breakfast, lunch, and dinner. The volunteers' average consumption of BPA, estimated from the urinary excretion of total BPA ((TOT)BPA = conjugated BPA + BPA), was 0.27 μg/kg body weight (range, 0.03-0.86), 21% greater than the 95th percentile of aggregate exposure in the adult U.S. population. A serum time course of (TOT)BPA was observable only in individuals with exposures 1.3-3.9 times higher than the 95th percentile of aggregate U.S. exposure. The (TOT)BPA urine concentration T(max) was 2.75 h (range, 0.75-5.75 h) post-meal, lagging the serum concentration T(max) by ∼1 h. Serum (TOT)BPA area under the curve per unit BPA exposure was between 21.5 and 79.0 nM•h•kg/μg BPA. Serum (TOT)BPA concentrations ranged from less than or equal to limit of detection (LOD, 1.3 nM) to 5.7 nM and were, on average, 42 times lower than urine concentrations. During these high dietary exposures, (TOT)BPA concentrations in serum were undetectable in 83% of the 320 samples collected and BPA concentrations were determined to be less than or equal to LOD in all samples.