NAD+ biosynthesis ameliorates a zebrafish model of muscular dystrophy.

Muscular dystrophies are common, currently incurable diseases. A subset of dystrophies result from genetic disruptions in complexes that attach muscle fibers to their surrounding extracellular matrix microenvironment. Cell-matrix adhesions are exquisite sensors of physiological conditions and mediate responses that allow cells to adapt to changing conditions. Thus, one approach towards finding targets for future therapeutic applications is to identify cell adhesion pathways that mediate these dynamic, adaptive responses in vivo. We find that nicotinamide riboside kinase 2b-mediated NAD+ biosynthesis, which functions as a small molecule agonist of muscle fiber-extracellular matrix adhesion, corrects dystrophic phenotypes in zebrafish lacking either a primary component of the dystrophin-glycoprotein complex or integrin alpha7. Exogenous NAD+ or a vitamin precursor to NAD+ reduces muscle fiber degeneration and results in significantly faster escape responses in dystrophic embryos. Overexpression of paxillin, a cell adhesion protein downstream of NAD+ in this novel cell adhesion pathway, reduces muscle degeneration in zebrafish with intact integrin receptors but does not improve motility. Activation of this pathway significantly increases organization of laminin, a major component of the extracellular matrix basement membrane. Our results indicate that the primary protective effects of NAD+ result from changes to the basement membrane, as a wild-type basement membrane is sufficient to increase resilience of dystrophic muscle fibers to damage. The surprising result that NAD+ supplementation ameliorates dystrophy in dystrophin-glycoprotein complex- or integrin alpha7-deficient zebrafish suggests the existence of an additional laminin receptor complex that anchors muscle fibers to the basement membrane. We find that integrin alpha6 participates in this pathway, but either integrin alpha7 or the dystrophin-glycoprotein complex is required in conjunction with integrin alpha6 to reduce muscle degeneration. Taken together, these results define a novel cell adhesion pathway that may have future therapeutic relevance for a broad spectrum of muscular dystrophies.

Pharmacokinetics of vildagliptin in patients with varying degrees of renal impairment.

OBJECTIVE: The kidney plays a key role in both the metabolism and excretion of vildagliptin. This study was designed to investigate the effects of varying degrees of renal impairment (RI) on the pharmacokinetics of vildagliptin. METHODS: A total of 96 subjects were enrolled, and each subject received vildagliptin 50 mg dosed orally once daily for 14 days. Vildagliptin and metabolite concentrations in plasma and urine were measured on Days 1 and 14. RESULTS: Compared to age-, gender-, BMI-matched subjects with normal renal function, the mean AUC of vildagliptin after 14 days in patients with mild, moderate, and severe RI increased by 40%, 71%, and 100%, respectively, and the Cmax of vildagliptin showed similar and minimal increases of 37%, 32% and 36%, respectively. CONCLUSIONS: These pharmacokinetics results suggest that 50 mg once daily is an appropriate dose and recommended for patients with moderate and severe renal impairment.

Metabolism and pharmacokinetics of indacaterol in humans.

The metabolism, pharmacokinetics, and excretion of [(14)C]indacaterol were investigated in healthy male subjects. Although indacaterol is administered to patients via inhalation, the dose in this study was administered orally. This was done to avoid the complications and concerns associated with the administration of a radiolabeled compound via the inhalation route. The submilligram doses administered in this study made metabolite identification and structural elucidation by mass spectrometry especially challenging. In serum, the mean t(max), C(max), and AUC(0-last) values were 1.75 h, 0.47 ng/ml, and 1.81 ng · h/ml for indacaterol and 2.5 h, 1.4 ngEq/ml, and 27.2 ngEq · h/ml for total radioactivity. Unmodified indacaterol was the most abundant drug-related compound in the serum, contributing 30% to the total radioactivity in the AUC(0-24h) pools, whereas monohydroxylated indacaterol (P26.9), the glucuronide conjugate of P26.9 (P19), and the 8-O-glucuronide conjugate of indacaterol (P37) were the most abundant metabolites, with each contributing 4 to 13%. In addition, the N-glucuronide (2-amino) conjugate (P37.7) and two metabolites (P38.2 and P39) that resulted from the cleavage about the aminoethanol group linking the hydroxyquinolinone and diethylindane moieties had a combined contribution of 12.5%. For all four subjects in the study, ≥90% of the radioactivity dose was recovered in the excreta (85% in feces and 10% in urine, mean values). In feces, unmodified indacaterol and metabolite P26.9 were the most abundant drug-related compounds (54 and 17% of the dose, respectively). In urine, unmodified indacaterol accounted for ∼0.3% of the dose, with no single metabolite accounting for >1.3%.

A molecular and serological survey in Taiwan to determine the true risk of babesiosis in dogs not receiving regular tick prevention.

Canine babesiosis is an important tick-borne disease worldwide. The prevalence varies between regions and countries; however, the incidence of tick infection is associated with the status of preventive tick control measures by the owner. To date, no studies have investigated the incidence of canine babesiosis and the condition of tick prevention in Taiwan. Therefore, the true risk of babesiosis could be underestimated in dogs that are not receiving tick prophylaxis. Samples were collected at 51 hospitals around Taiwan from 265 dogs not receiving regular tick prophylaxis. Diagnostic real-time PCR was performed, and 28 dogs (10.6%) were positive for Babesia spp., including B. gibsoni (26/28) and B. vogeli (2/28). Thirty-nine dogs (14.7%) were seropositive to B. gibsoni. Take the real-time PCR positive as the Babesia infected case, the positive and negative predictive value of serological assay were 64.1% and 98.7%, respectively. The seropositivity of B. gibsoni was significantly associated with real-time PCR positivity for Babesia spp. and vice versa (p < 0.001). The odds of seropositive representing real-time PCR positivity was 132.7 times greater than the seronegative (OR: 132.731, 95% CI 35.683-493.728). Risk factors in the population identified included: dogs with a short-haired coat; intact dogs; dogs from multi-dog households; dogs with more than 10 ticks and fleas on the skin; dogs that go outdoors more than 9 times per week; and dogs with an abnormal blood test result that included anemia, thrombocytopenia, and leukopenia. However, the dogs were not tested for other co-infections, therefore, these hematological risk factors should be carefully interpreted and confirmed by further diagnostic tests. In conclusion, when dogs present with abnormal blood test results and share the risk factors listed above, babesiosis should be seriously considered and followed up with molecular and serological testing. The serological assay used in this study can provide valuable information in diagnosing babesiosis in dogs in Taiwan.

Early clinical development of artemether-lumefantrine dispersible tablet: palatability of three flavours and bioavailability in healthy subjects.

BACKGROUND: Efforts to ease administration and enhance acceptability of the oral anti-malarial artemether-lumefantrine (A-L) crushed tablet to infants and children triggered the development of a novel dispersible tablet of A-L. During early development of this new formulation, two studies were performed in healthy subjects, one to evaluate the palatability of three flavours of A-L, and a second one to compare the bioavailability of active principles between the dispersible tablet and the tablet (administered crushed and intact). METHODS: Study 1 was performed in 48 healthy schoolchildren in Tanzania. Within 1 day, all subjects tasted a strawberry-, orange- and cherry-flavoured oral A-L suspension for 10 seconds (without swallowing) in a randomized, single-blind, crossover fashion. The palatability of each formulation was rated using a visual analogue scale (VAS). Study 2 was an open, randomized crossover trial in 48 healthy adults given single doses of A-L (80 mg artemether + 480 mg lumefantrine) with food. The objectives were to compare the bioavailability of artemether, dihydroartemisinin (DHA) and lumefantrine between the dispersible tablet and the tablet administered crushed (primary objective) and intact (secondary objective). RESULTS: Study 1 showed no statistically significant difference in VAS scores between the three flavours but cherry had the highest score in several ratings (particularly for overall liking). Study 2 demonstrated that the dispersible and crushed tablets delivered bioequivalent artemether, DHA and lumefantrine systemic exposure (area under the curve [AUC]); mean ± SD AUC0-tlast were 208 ± 113 vs 195 ± 93 h.ng/ml for artemether, 206 ± 81 vs 199 ± 84 h.ng/ml for DHA and 262 ± 107 vs 291 ± 106 h x µg/ml for lumefantrine. Bioequivalence was also shown for peak plasma concentrations (Cmax) of DHA and lumefantrine. Compared with the intact tablet, the dispersible tablet resulted in bioequivalent lumefantrine exposure, but AUC and Cmax values of artemether and DHA were 20-35% lower. CONCLUSIONS: Considering that cherry was the preferred flavour, and that the novel A-L dispersible tablet demonstrated similar pharmacokinetic performances to the tablet administered crushed, a cherry-flavoured A-L dispersible tablet formulation was selected for further development and testing in a large efficacy and safety study in African children with malaria.

Pharmacokinetics of the oral direct renin inhibitor aliskiren in combination with digoxin, atorvastatin, and ketoconazole in healthy subjects: the role of P-glycoprotein in the disposition of aliskiren.

This study investigated the potential pharmacokinetic interaction between the direct renin inhibitor aliskiren and modulators of P-glycoprotein and cytochrome P450 3A4 (CYP3A4). Aliskiren stimulated in vitro P-glycoprotein ATPase activity in recombinant baculovirus-infected Sf9 cells with high affinity (K(m) 2.1 micromol/L) and was transported by organic anion-transporting peptide OATP2B1-expressing HEK293 cells with moderate affinity (K(m) 72 micromol/L). Three open-label, multiple-dose studies in healthy subjects investigated the pharmacokinetic interactions between aliskiren 300 mg and digoxin 0.25 mg (n = 22), atorvastatin 80 mg (n = 21), or ketoconazole 200 mg bid (n = 21). Coadministration with aliskiren resulted in changes of <30% in AUC(tau) and C(max,ss) of digoxin, atorvastatin, o-hydroxy-atorvastatin, and rho-hydroxy-atorvastatin, indicating no clinically significant interaction with P-glycoprotein or CYP3A4 substrates. Aliskiren AUC(tau) was significantly increased by coadministration with atorvastatin (by 47%, P < .001) or ketoconazole (by 76%, P < .001) through mechanisms most likely involving transporters such as P-glycoprotein and organic anion-transporting peptide and possibly through metabolic pathways such as CYP3A4 in the gut wall. These results indicate that aliskiren is a substrate for but not an inhibitor of P-glycoprotein. On the basis of the small changes in exposure to digoxin and atorvastatin and the <2-fold increase in exposure to aliskiren during coadministration with atorvastatin and ketoconazole, the authors conclude that the potential for clinically relevant drug interactions between aliskiren and these substrates and/or inhibitors of P-glycoprotein/CPY3A4/OATP is low.

Bioequivalence of Canakinumab Injected Subcutaneously via an Autoinjector Device or a Prefilled Safety Syringe Device in Healthy Subjects.

Canakinumab, a high-affinity human anti-interleukin-1ß monoclonal antibody, is being used for the treatment of a broad spectrum of inflammatory diseases. This phase 1 study compared the relative bioavailability of a single dose of subcutaneous canakinumab either self-administered with an autoinjector (AI) or administered by a health care professional (HCP) with a prefilled safety syringe (SS) in healthy subjects. The study enrolled 80 subjects randomized 1:1 to receive 150 mg/mL of a liquid formulation of canakinumab via an AI or SS into either the thigh or abdomen. The geometric mean ratio (90% confidence interval [CI]) of Cmax was 1.09 (0.97-1.21), AUClast was 1.06 (0.96-1.17), and AUCinf was 1.05 (0.94-1.18) for the AI versus SS. The 2-sided 90%CIs that compared self-administration with the AI versus administration by an HCP using the SS were entirely within the bioequivalence limits of 80%-125%. Two subjects in the AI group and 1 in the SS group experienced mild injection-site reactions. No immunogenicity response was detected in the 307 samples analyzed for immunogenicity. No discontinuations because of adverse events were reported in this trial. Canakinumab administration with an AI or SS has a comparable bioavailability, meeting bioequivalence criteria.

Pharmacokinetics, safety, and tolerability of the novel oral direct renin inhibitor aliskiren in elderly healthy subjects.

This open-label, multicenter study compared the pharmacokinetics and safety of the oral direct renin inhibitor aliskiren in 29 elderly (>or=65 years) and 28 young (18-45 years) healthy subjects. Plasma drug concentrations were determined for up to 168 hours following a single 300-mg oral dose of aliskiren. In elderly compared with young subjects, AUC(0-infinity) was 57% higher (ratio of geometric means 1.57, 90% confidence interval: 1.19, 2.06; P = .008) and C(max) was 28% higher (1.28, 90% confidence interval: 0.91, 1.79; P=.233). Other parameters, including t(max) and Vd/F, were similar between age groups. No differences in aliskiren exposure were observed between subjects ages 65 to 74 years (n=16) and >or=75 years (n=13). Aliskiren was well tolerated by all age groups, including the very elderly. In conclusion, aliskiren exposure is modestly increased in elderly subjects. Based on its wide therapeutic index and shallow dose response for blood pressure lowering, no initial dose adjustment should be needed for elderly patients.

Physician-stakeholder collaboration in Disability Management: a Canadian perspective on guidelines and expectations.

PURPOSE: The physician plays a vital role in Disability Management; unfortunately, there is an apparent lack of clarity with respect to the functions included in this role. The present article reviews the collaborative nature of the physician-stakeholder relationship giving attention to types of expectations, current Canadian guidelines and future challenges. CONCLUSION: The authors conclude that although challenging and complex, the physician's performance in Disability Management can be optimized through improved communication and collaboration with stakeholders.

Pharmacokinetic drug-drug interaction assessment of LCZ696 (an angiotensin receptor neprilysin inhibitor) with omeprazole, metformin or levonorgestrel-ethinyl estradiol in healthy subjects.

LCZ696 is a novel angiotensin receptor neprilysin inhibitor in development for the treatment of cardiovascular diseases. Here, we assessed the potential for pharmacokinetic drug-drug interaction of LCZ696 (400 mg, single dose or once daily [q.d.]) when co-administered with omeprazole 40 mg q.d. (n = 28) or metformin 1000 mg q.d. (n = 27) or levonorgestrel-ethinyl estradiol 150/30 µg single dose (n = 24) in three separate open-label, single-sequence studies in healthy subjects. Pharmacokinetic parameters of LCZ696 analytes (sacubitril, LBQ657, and valsartan), metformin, and levonorgestrel-ethinyl estradiol were assessed. Omeprazole did not alter the AUCinf of sacubitril and pharmacokinetics of LBQ657; however, 7% decrease in the Cmax of sacubitril, and 11% and 13% decreases in AUCinf and Cmax of valsartan were observed. Co-administration of LCZ696 with metformin had no significant effect on the pharmacokinetics of LBQ657 and valsartan; however, AUCtau,ss and Cmax,ss of metformin were decreased by 23%. Co-administration of LCZ696 with levonorgestrel-ethinyl estradiol had no effect on the pharmacokinetics of ethinyl estradiol and LBQ657 or AUCinf of levonorgestrel. The Cmax of levonorgestrel decreased by 15%, and AUCtau,ss and Cmax,ss of valsartan decreased by 14% and 16%, respectively. Co-administration of LCZ696 with omeprazole, metformin, or levonorgestrel-ethinyl estradiol was not associated with any clinically relevant pharmacokinetic drug interactions.

Lack of effect of omeprazole or of an aluminium hydroxide/magnesium hydroxide antacid on the pharmacokinetics of lumiracoxib.

OBJECTIVE: To evaluate the effects of multiple doses of omeprazole and of a single dose of an aluminium hydroxide/magnesium hydroxide (Al/Mg) antacid on the single-dose plasma pharmacokinetics of lumiracoxib. STUDY DESIGN: Open-label, randomised, three-period, crossover study. POPULATION STUDIED: Healthy subjects aged 18-65 years. METHODS: Fourteen subjects who met eligibility criteria were each administered three treatments in random order: (A) lumiracoxib 400 mg as a single oral dose; (B) oral omeprazole 20 mg once daily for 4 consecutive days, then lumiracoxib 400 mg as a single oral dose just prior to oral omeprazole 20 mg on day 5; and (C) lumiracoxib 400 mg as a single oral dose immediately prior to a 20 mL dose of Al/Mg antacid (magnesium hydroxide 800 mg and aluminium hydroxide 900 mg). The interval between each lumiracoxib dose was 7 days. Analysis of variance was performed to determine whether lumiracoxib alone differed from lumiracoxib plus omeprazole or from lumiracoxib plus Al/Mg antacid for overall exposure (area under the concentration-time curve from zero to infinity [AUC( infinity )]) and peak concentration (C(max)), with treatment sequence, subject, period and treatment as factors. Ratios of geometric means between lumiracoxib plus omeprazole and lumiracoxib plus Al/Mg antacid to lumiracoxib alone (reference) were calculated for AUC( infinity ) and C(max). If the mean ratios, with 90% CIs, fell within the interval 0.80-1.25, the treatments were considered equivalent. RESULTS: Arithmetic mean plasma lumiracoxib concentration-time profiles were similar for all treatments, with a rapid rise in concentration after administration, reaching C(max) values (mean +/- SD) of 9.24 +/- 1.96, 8.81 +/- 2.30, and 10.43 +/- 3.24 mg/L within 2-3 hours for treatments A, B and C, respectively. AUC( infinity ) was similar for the three treatments (36.75 +/- 7.73, 34.88 +/- 8.40 and 35.50 +/- 5.72 mg. h/L). All ratios of geometric means with 90% CIs fell within the interval used for establishing bioequivalence, except for the C(max) comparison between lumiracoxib plus Al/Mg antacid and lumiracoxib alone, which was 1.11 (0.95, 1.31). CONCLUSIONS: Coadministration of lumiracoxib with omeprazole or with an Al/Mg antacid had no clinically significant effect on lumiracoxib single-dose plasma pharmacokinetics. Lumiracoxib can, therefore, be administered concurrently with either of these agents without need for lumiracoxib dosage alteration.

Pharmacokinetics of lumiracoxib in plasma and synovial fluid.

BACKGROUND: Lumiracoxib is a new cyclo-oxygenase-2 (COX-2) selective inhibitor in development for the treatment of rheumatoid arthritis, osteoarthritis and acute pain. OBJECTIVE: To investigate the pharmacokinetics of lumiracoxib in plasma and knee joint synovial fluid from patients with rheumatoid arthritis. DESIGN: Open-label multiple-dose study evaluating the steady-state pharmacokinetics of lumiracoxib in plasma and synovial fluid after 7 days of treatment with lumiracoxib 400 mg once daily. PATIENT POPULATION: Males and females aged 18-75 years with rheumatoid arthritis, having moderate to significant synovial fluid effusion of the knee. OUTCOME MEASURES: Following a 7-day washout period for previous nonsteroidal anti-inflammatory drugs, 22 patients (17 female, 5 male) received lumiracoxib 400 mg once daily for seven consecutive days. On day 7, following an overnight fast, a final dose of lumiracoxib was administered and serial blood and synovial fluid samples were collected for up to 28 hours. Lumiracoxib and its metabolites (4'-hydroxy-lumiracoxib and 5-carboxy-4'-hydroxy-lumiracoxib) were measured by validated high performance liquid chromatography-mass spectrometry methods. The steady-state pharmacokinetics of lumiracoxib were evaluated in plasma and synovial fluid by both a population pharmacokinetic model and noncompartmental analysis. RESULTS: Lumiracoxib was rapidly absorbed (peak plasma concentration at 2 hours) and the terminal elimination half-life in plasma was short (6 hours). Lumiracoxib concentrations were initially higher in plasma than in synovial fluid; however, from 5 hours after administration until the end of the 28-hour assessment period, concentrations of lumiracoxib were higher in synovial fluid than in plasma. Peak drug concentration in synovial fluid occurred 3-4 hours later than the peak plasma concentration. The mean steady-state trough concentration of lumiracoxib in synovial fluid (454 microg/L) was approximately three times higher than the mean value in plasma (155 microg/L), and the area under the concentration-time curve from 12 to 24 hours after administration was 2.6-fold higher for synovial fluid than for plasma. Median lumiracoxib protein binding was similar in plasma and synovial fluid (range 97.9-98.3%). Concentrations of 4'-hydroxy-lumiracoxib, the active COX-2 selective metabolite, remained low in comparison with parent drug in both plasma and synovial fluid. The concentration of lumiracoxib in synovial fluid at 24 hours after administration would be expected to result in substantial inhibition of prostaglandin E(2) formation. CONCLUSION: The kinetics of distribution of lumiracoxib in synovial fluid are likely to extend the therapeutic action of the drug beyond that expected from plasma pharmacokinetics. These data support the use of lumiracoxib in a once-daily regimen for the treatment of rheumatoid arthritis.

Effect of food on the oral bioavailability of amlodipine/valsartan and amlodipine/valsartan/hydrochlorothiazide fixed dose combination tablets in healthy subjects.

A double fixed dose combination of amlodipine/valsartan and triple fixed dose combination of amlodipine/valsartan/HCTZ tablets have been developed to treat patients with moderate-to-severe hypertension. Here, we present the effect of food on the oral bioavailability of these two fixed dose combination tablets from two separate clinical studies in healthy subjects. Single oral doses of amlodipine/valsartan (10/160 mg) and amlodipine/valsartan/HCTZ (10/320/25 mg were administered under fasted or fed conditions. Blood samples were collected in both studies to determine the pharmacokinetic parameters of amlodipine, valsartan, and/or HCTZ using non-compartmental analysis. Following amlodipine/valsartan administration, the geometric mean ratios (GMRs, 90% CI) of AUC0-∞ and Cmax were 1.09 (1.05-1.13) and 1.03 (0.97-1.09) for amlodipine, and 0.94 (0.81-1.10) and 0.86 (0.73-1.02) for valsartan, respectively. Following amlodipine/valsartan/HCTZ administration, the GMRs (90%CI) of AUC0-∞ and Cmax were 1.09 (1.04-1.15) and 1.11 (1.05-1.08) for amlodipine, 1.14 (0.99-1.31) and 1.12 (0.98-1.29) for valsartan, and 1.09 (1.02-1.16) and 0.86 (0.79-0.93) for HCTZ, respectively. Considering the sample size and pharmacokinetic variability associated with analytes, these study results indicate that food effect is minimal or none when fixed dose combination tablets are administered with food. In conclusion, both fixed dose combination tablets can be administered without regards to meals.

Evaluation of a pharmacokinetic interaction between valsartan and simvastatin in healthy subjects.

OBJECTIVE: The potential for a pharmacokinetic drug interaction between valsartan, an antihypertensive drug, and simvastatin, a lipid-lowering agent, was investigated in this study. This was an open-label, multiple-dose, randomized, three-period, cross over study in 18 healthy subjects. Each subject received one 160 mg valsartan tablet or one 40 mg simvastatin tablet or co-administration of valsartan (160 mg) and simvastatin (40 mg) tablets for 7 days, with a 7-day inter-dose washout period. The steady-state pharmacokinetics of valsartan, simvastatin beta-hydroxy acid (active metabolite of simvastatin) and simvastatin (pro-drug) were determined on day 7 of each dosing period. RESULTS: The results were interpreted based on the point estimates and the 90% confidence intervals. These results indicated that the area under the curve of plasma concentration from 0 to 24 hours (AUC(0-24)) of valsartan, simvastatin beta-hydroxy acid and simvastatin was increased by 14%, 19%, and 23%, respectively, with the combination treatment. In addition, the maximum concentration (C(max)) of valsartan and simvastatin beta-hydroxy acid was increased by 10% and 22%, respectively, and the C(max) of simvastatin was decreased by 26% with the combination treatment. All treatments were safe and well tolerated. CONCLUSIONS: Based on the wide therapeutic dosage ranges of valsartan and simvastatin, and the highly variable pharmacokinetics of three analytes, the observed differences in the exposure and C(max) of valsartan, simvastatin beta-hydroxy acid and simvastatin in the combination treatment are unlikely to be of clinical relevance.