Pharmacokinetics and Pharmacodynamics of the SGLT2 Inhibitor Remogliflozin Etabonate in Subjects with Mild and Moderate Renal Impairment.

Remogliflozin etabonate (RE), the prodrug of remogliflozin, is an inhibitor of the sodium glucose-dependent renal transporter 2 (SGLT2), enabling urinary glucose excretion to reduce hyperglycemia for the treatment of type 2 diabetes. Renal function declines more rapidly in patients with type 2 diabetes, making it difficult or unsafe to continue on some antidiabetic therapeutics. In an initial effort to understand the potential utility of RE in patients with renal impairment, the pharmacodynamics and pharmacokinetics of RE were evaluated in a single oral dose (250 mg) in patients with renal impairment as compared with control subjects. As shown by pharmacodynamic measurements of urinary glucose excretion, there was no clinically significant reduction in the ability of remogliflozin to inhibit SGLT2. In addition, there were no significant changes in area under the curve (from 0 to infinity) or half-life of remogliflozin, suggesting renal impairment does not alter the pharmacokinetics of remogliflozin. In contrast to other SGLT2 inhibitors which accumulate in patients with renal impairment, adjustment of the dosage of RE in subjects with mild or moderate renal impairment is not indicated based on the observations in this study.

Safety, pharmacokinetics and pharmacodynamics of remogliflozin etabonate, a novel SGLT2 inhibitor, and metformin when co-administered in subjects with type 2 diabetes mellitus.

BACKGROUND: The sodium-dependent glucose co-transporter-2 (SGLT2) is expressed in absorptive epithelia of the renal tubules. Remogliflozin etabonate (RE) is the prodrug of remogliflozin, the active entity that inhibits SGLT2. An inhibitor of this pathway would enhance urinary glucose excretion (UGE), and potentially improve plasma glucose concentrations in diabetic patients. RE is intended for use for the treatment of type 2 diabetes mellitus (T2DM) as monotherapy and in combination with existing therapies. Metformin, a dimethylbiguanide, is an effective oral antihyperglycemic agent widely used for the treatment of T2DM. METHODS: This was a randomized, open-label, repeat-dose, two-sequence, cross-over study in 13 subjects with T2DM. Subjects were randomized to one of two treatment sequences in which they received either metformin alone, RE alone, or both over three, 3-day treatment periods separated by two non-treatment intervals of variable duration. On the evening before each treatment period, subjects were admitted and confined to the clinical site for the duration of the 3-day treatment period. Pharmacokinetic, pharmacodynamic (urine glucose and fasting plasma glucose), and safety (adverse events, vital signs, ECG, clinical laboratory parameters including lactic acid) assessments were performed at check-in and throughout the treatment periods. Pharmacokinetic sampling occurred on Day 3 of each treatment period. RESULTS: This study demonstrated the lack of effect of RE on steady state metformin pharmacokinetics. Metformin did not affect the AUC of RE, remogliflozin, or its active metabolite, GSK279782, although Cmax values were slightly lower for remogliflozin and its metabolite after co-administration with metformin compared with administration of RE alone. Metformin did not alter the pharmacodynamic effects (UGE) of RE. Concomitant administration of metformin and RE was well tolerated with minimal hypoglycemia, no serious adverse events, and no increase in lactic acid. CONCLUSIONS: Coadministration of metformin and RE was well tolerated in this study. The results support continued development of RE as a treatment for T2DM. TRIAL REGISTRATION: ClinicalTrials.gov, NCT00376038.

First human dose-escalation study with remogliflozin etabonate, a selective inhibitor of the sodium-glucose transporter 2 (SGLT2), in healthy subjects and in subjects with type 2 diabetes mellitus.

BACKGROUND: Remogliflozin etabonate (RE) is the prodrug of remogliflozin, a selective inhibitor of the renal sodium-dependent glucose transporter 2 (SGLT2), which could increase urine glucose excretion (UGE) and lower plasma glucose in humans. METHODS: This double-blind, randomized, placebo-controlled, single-dose, dose-escalation, crossover study is the first human trial designed to evaluate safety, tolerability, pharmacokinetics (PK) and pharmacodynamics of RE. All subjects received single oral doses of either RE or placebo separated by approximately 2 week intervals. In Part A, 10 healthy subjects participated in 5 dosing periods where they received RE (20 mg, 50 mg, 150 mg, 500 mg, or 1000 mg) or placebo (4:1 active to placebo ratio per treatment period). In Part B, 6 subjects with type 2 diabetes mellitus (T2DM) participated in 3 dose periods where they received RE (50 mg and 500 mg) or placebo (2:1 active to placebo per treatment period). The study protocol was registered with the NIH clinical trials data base with identifier NCT01571661. RESULTS: RE was generally well-tolerated; there were no serious adverse events. In both populations, RE was rapidly absorbed and converted to remogliflozin (time to maximum plasma concentration [Cmax;Tmax] approximately 1 h). Generally, exposure to remogliflozin was proportional to the administered dose. RE was rapidly eliminated (mean T½ of ~25 min; mean plasma T½ for remogliflozin was 120 min) and was independent of dose. All subjects showed dose-dependent increases in 24-hour UGE, which plateaued at approximately 200 to 250 mmol glucose with RE doses ≥150 mg. In T2DM subjects, increased plasma glucose following OGTT was attenuated by RE in a drug-dependent fashion, but there were no clear trends in plasma insulin. There were no apparent effects of treatment on plasma or urine electrolytes. CONCLUSIONS: The results support progression of RE as a potential treatment for T2DM. TRIAL REGISTRATION: ClinicalTrials.gov NCT01571661.

Assessment of the drug interaction risk for remogliflozin etabonate, a sodium-dependent glucose cotransporter-2 inhibitor: evidence from in vitro, human mass balance, and ketoconazole interaction studies.

Remogliflozin etabonate is the ester prodrug of remogliflozin, a selective sodium-dependent glucose cotransporter-2 inhibitor. This work investigated the absorption, metabolism, and excretion of [(14)C]remogliflozin etabonate in humans, as well as the influence of P-glycoprotein (Pgp) and cytochrome P450 (P450) enzymes on the disposition of remogliflozin etabonate and its metabolites to understand the risks for drug interactions. After a single oral 402 ± 1.0 mg (106 ± 0.3 µCi) dose, [(14)C]remogliflozin etabonate is rapidly absorbed and extensively metabolized. The area under the concentration-time curve from 0 to infinity [AUC((0-∞))] of plasma radioactivity was approximately 14-fold higher than the sum of the AUC((0-∞)) of remogliflozin etabonate, remogliflozin, and 5-methyl-4-({4-[(1-methylethyl)oxy]phenyl}methyl)-1H-pyrazol-3-yl-ß-d-glucopyranoside (GSK279782), a pharmacologically active N-dealkylated metabolite. Elimination half-lives of total radioactivity, remogliflozin etabonate, and remogliflozin were 6.57, 0.39, and 1.57 h, respectively. Products of remogliflozin etabonate metabolism are eliminated primarily via renal excretion, with 92.8% of the dose recovered in the urine. Three glucuronide metabolites made up the majority of the radioactivity in plasma and represent 67.1% of the dose in urine, with 5-methyl-1-(1-methylethyl)-4-({4-[(1-methylethyl)oxy]phenyl}methyl)-1H-pyrazol-3-yl-ß-d-glucopyranosiduronic acid (GSK1997711) representing 47.8% of the dose. In vitro studies demonstrated that remogliflozin etabonate and remogliflozin are Pgp substrates, and that CYP3A4 can form GSK279782 directly from remogliflozin. A ketoconazole clinical drug interaction study, along with the human mass balance findings, confirmed that CYP3A4 contributes less than 50% to remogliflozin metabolism, demonstrating that other enzyme pathways (e.g., P450s, UDP-glucuronosyltransferases, and glucosidases) make significant contributions to the drug's clearance. Overall, these studies support a low clinical drug interaction risk for remogliflozin etabonate due to the availability of multiple biotransformation pathways.

Multiple-dose pharmacokinetics and pharmacodynamics of sergliflozin etabonate, a novel inhibitor of glucose reabsorption, in healthy overweight and obese subjects: a randomized double-blind study.

Sergliflozin, the active entity of sergliflozin etabonate, is a selective inhibitor of the sodium-dependent glucose cotransporter-2 in the renal tubule. The pharmacokinetics and pharmacodynamics of sergliflozin were examined during administration of sergliflozin etabonate (500 or 1000 mg) or placebo 3 times daily (tid) for 14 days in healthy overweight or obese human volunteers (n = 18). At the doses tested, sergliflozin showed less than dose-proportional pharmacokinetic characteristics. Mean half-life of the active entity was approximately 2 hours; there was no evidence of drug accumulation. Sergliflozin etabonate produced rapid and sustained suppression of renal glucose reabsorption, resulting in a dose-related glucosuria, and a transient increase in urinary electrolyte and fluid loss; plasma glucose, insulin, and electrolyte levels were unchanged. Sergliflozin etabonate produced a rapid, dose-related reduction in body weight (mean changes of -0.09, -1.55, and -1.74 kg from baseline to day 15 with placebo, sergliflozin etabonate 500 mg, and sergliflozin etabonate 1000 mg, respectively), apparently through increased urinary calorie loss rather than through osmotic diuresis. Sergliflozin etabonate 500 or 1000 mg tid was generally well tolerated; no clinically significant adverse events were identified. Renal function (creatinine clearance) was not affected by sergliflozin etabonate, although urinary microalbumin, N-acetyl-beta-D-glucosaminidase, and beta(2)-microglobulin levels tended to increase.

Structural and functional analysis of rice genome.

Rice is an excellent system for plant genomics as it represents a modest size genome of 430 Mb. It feeds more than half the population of the world. Draft sequences of the rice genome, derived by whole-genome shotgun approach at relatively low coverage (4-6 X), were published and the International Rice Genome Sequencing Project (IRGSP) declared high quality (>10 X), genetically anchored, phase 2 level sequence in 2002. In addition, phase 3 level finished sequence of chromosomes 1, 4 and 10 (out of 12 chromosomes of rice) has already been reported by scientists from IRGSP consortium. Various estimates of genes in rice place the number at >50,000. Already, over 28,000 full-length cDNAs have been sequenced, most of which map to genetically anchored genome sequence. Such information is very useful in revealing novel features of macro- and micro-level synteny of rice genome with other cereals. Microarray analysis is unraveling the identity of rice genes expressing in temporal and spatial manner and should help target candidate genes useful for improving traits of agronomic importance. Simultaneously, functional analysis of rice genome has been initiated by marker-based characterization of useful genes and employing functional knock-outs created by mutation or gene tagging. Integration of this enormous information is expected to catalyze tremendous activity on basic and applied aspects of rice genomics.

Sequence analysis of the long arm of rice chromosome 11 for rice-wheat synteny.

The DNA sequence of 106 BAC/PAC clones in the minimum tiling path (MTP) of the long arm of rice chromosome 11, between map positions 57.3 and 116.2 cM, has been assembled to phase 2 or PLN level. This region has been sequenced to 10x redundancy by the Indian Initiative for Rice Genome Sequencing (IIRGS) and is now publicly available in GenBank. The region, excluding overlaps, has been predicted to contain 2,932 genes using different software. A gene-by-gene BLASTN search of the NCBI wheat EST database of over 420,000 cDNA sequences revealed that 1,143 of the predicted rice genes (38.9%) have significant homology to wheat ESTs (bit score >/= 100). Further BLASTN search of these 1,143 rice genes with the GrainGenes database of sequence contigs containing bin-mapped wheat ESTs allowed 113 of the genes to be placed in bins located on wheat chromosomes of different homoeologous groups. The largest number of genes, about one-third, mapped to the homoeologous group 4 chromosomes of wheat, suggesting a common evolutionary origin. The remaining genes were located on wheat chromosomes of different groups with significantly higher numbers for groups 3 and 5. Location of bin-mapped wheat contigs to chromosomes of all the seven homoeologous groups can be ascribed to movement of genes (transpositions) or chromosome segments (translocations) within rice or the hexaploid wheat genomes. Alternatively, it could be due to ancient duplications in the common ancestral genome of wheat and rice followed by selective elimination of genes in the wheat and rice genomes. While there exists definite conservation of gene sequences and the ancestral chromosomal identity between rice and wheat, there is no obvious conservation of the gene order at this level of resolution. Lack of extensive colinearity between rice and wheat genomes suggests that there have been many insertions, deletions, duplications and translocations that make the synteny comparisons much more complicated than earlier thought. However, enhanced resolution of comparative sequence analysis may reveal smaller conserved regions of colinearity, which will facilitate selection of markers for saturation mapping and sequencing of the gene-rich regions of the wheat genome.

Evaluation of parameters for high efficiency gene transfer via particle bombardment in Indian mulberry.

Particle bombardment is a popular method of direct gene delivery into cell, tissue and organs since it requires minimum pre- and post-bombardment manipulation. In addition, this technique is much easier and fast to perform with intact tissue/organ and reduces the period of in vitro culture. Genetic transformation of mulberry, Morus indica cv. K2 was attempted by particle bombardment using hypocotyl, cotyledon, leaf and leaf callus explants. The effect of various physical and biological parameters during bombardment were studied by the histochemical localization of GUS reporter gene following two days of bombardment and by assessing the number of blue spots per explant. p35SGUSINT was used for optimization of different parameters. The percentage of GUS positive explants was very low with tungsten (20%) as compared to gold particles (36%) indicating tungsten toxicity to the tissue. Maximum GUS activity was observed at 1100 psi helium pressure and 9 cm target distance for hypocotyl, cotyledon and leaf. Double bombardment of explants with 10 microg of DNA loaded on macrocarriers clearly yielded a better (up to 56%) result as compared to a single bombardment (30%). Amongst the various plasmids tested, pBI221 gave the highest (100%) GUS positive explants in the leaf callus.