Our study results demonstrated for the first time the existence of genetic polymorphisms of OCT2 in the Chinese population, and further showed that the 808G>T polymorphism is associated with a reduced metformin renal or tubular clearance. Moreover, the inhibition of metformin renal tubular secretion by cimetidine also appeared to be dependent on this mutation.

This article describes studies that investigated the pharmacokinetics of nilotinib, a highly specific, oral, second-generation BCR-ABL tyrosine kinase inhibitor. After a once- or twice-daily regimen at doses ranging from 50 to 1,200 mg/day in 119 patients with chronic myeloid leukemia (CML), the area under the serum concentration-time curve (AUC) and peak serum concentration (C(max)) of nilotinib were found to be nearly dose proportional up to a dose of 400 mg once daily. Solubility-limited absorption at higher doses was observed, but this was partially overcome by dividing the daily dose into two. For instance, the administration of 400 mg nilotinib twice daily resulted in a 35% increase in AUC as compared to a once-daily dose of 800 mg. Exploratory pharmacodynamic assessment showed a general trend of greater reduction in white blood cell (WBC) levels with increase in nilotinib concentrations. This finding was consistent with the observation of an 82% reduction in WBC levels in patients after a regimen of 400 mg nilotinib twice daily for 15 days. The type and quantity of food intake variably affected nilotinib absorption. When administered after a high-fat meal, the AUC of nilotinib increased by 50% in CML patients (n = 10) and by 82% in healthy volunteers (n = 44).

Our study clarifies the relative importance of the gut, liver, and bile in the metabolism and excretion of quercetin and its conjugates. The pharmacokinetic model appears to be suitable for describing the absorption and disposition of the quercetin and its conjugates and may be applicable to other flavonoids that undergo similar pharmacokinetic pathways.

Purpose We investigated the population pharmacokinetics and exposure-response relationship of nilotinib in patients with newly diagnosed chronic myeloid leukemia (CML) in chronic phase. Methods Nilotinib was given at 300 mg or 400 mg twice daily. Serum concentration data (sparse and full pharmacokinetic profiles) were obtained from 542 patients over 12 months. A population pharmacokinetic analysis was performed using nonlinear mixed-effect modeling. Exposure-response relationships were explored graphically or using logistic regression models. Results Nilotinib concentrations were stable over 12 months. Patients in the 400 mg twice-daily arm had an 11.5% higher exposure than did those in the 300 mg twice-daily arm, and the relative bioavailability of nilotinib 400 mg twice daily was 0.84 times that of 300 mg twice daily. Patient demographics did not significantly affect nilotinib pharmacokinetics. The occurrence of all grade total bilirubin elevation was significantly higher in patients with higher nilotinib exposure, and a positive correlation was also observed between nilotinib exposure and QTcF change on electrocardiograms from baseline. There was no significant relationship between nilotinib exposure and major molecular response at 12 months. Conclusions There is a less than proportional dose-exposure relationship between nilotinib 300 mg and 400 mg twice-daily doses. Blood level testing is unlikely to play an important role in the general management of patients with newly diagnosed CML treated with nilotinib.

When tolerability allows, adherence to the nilotinib dose (400 mg twice daily) in order to maintain sufficient Cmin is important in maximizing the efficacy of nilotinib in patients with imatinib-resistant or -intolerant CML.

Nilotinib (Tasigna), an orally bioavailable second-generation BCR-ABL tyrosine kinase inhibitor, is approved for use in patients with chronic myeloid leukemia in chronic phase and accelerated phase who are resistant or intolerant to prior therapy, including imatinib. Previous in vitro studies indicated that nilotinib metabolism is primarily mediated by CYP3A4. To investigate the effect of CYP3A4 induction and inhibition on nilotinib pharmacokinetics, 2 studies were conducted in healthy volunteers prior to and following treatment with a strong inducer (rifampin) or inhibitor (ketoconazole). In the induction study, administration of rifampin 600 mg once daily for 8 days significantly increased urinary 6β-hydroxycortisol/ cortisol ratio, from a preinduction baseline of 5.8 ± 2.7 to 18.0 ± 10.2 after 8 days of rifampin treatment, confirming an inductive effect on CYP3A4. Nilotinib oral clearance was increased by 4.8-fold, and the maximum serum concentration (C(max)) and area under the serum concentration-time curve (AUC) were decreased by 64% and 80%, respectively, in the induced state compared with baseline. In the inhibition study, ketoconazole 400 mg once daily for 6 days increased the C(max) and AUC of nilotinib by 1.8- and 3-fold, respectively, compared with nilotinib alone. These results indicate that concurrent use of strong CYP3A4 inducers or inhibitors may necessitate dosage adjustments of nilotinib and should be avoided when possible.

Background Current treatments for acute ischemic stroke and venous thromboembolism, such as recombinant tissue-type plasminogen activator and thrombectomy, are limited by a narrow time window and the risk of bleeding. DS-1040 is a novel low molecular weight compound that inhibits the activated form of thrombin-activatable fibrinolysis inhibitor (TAFIa), and was developed as a fibrinolysis enhancer for the treatment of thromboembolic diseases. Objectives This first-in-human, randomized, placebo-controlled, three-part, phase 1 study was conducted to evaluate the safety, pharmacokinetics and pharmacodynamics of DS-1040 in healthy subjects. Subjects/Methods Young (18-45 years) or elderly (65-75 years) subjects (N = 103) were randomized to receive single ascending doses of DS-1040 ranging from 0.1 mg to 40 mg, or placebo, administered either as a 0.5-h intravenous infusion or as a 24-h continuous infusion. Results All doses of DS-1040 were tolerated, and no serious adverse events (AEs) or discontinuations resulting from AEs occurred during the study. Bleeding time remained within the normal range for all doses tested in all subjects. Plasma exposure of DS-1040 increased proportionally with increase in dose. Elderly subjects had higher exposures to DS-1040 and prolonged elimination times, probably because of decreased renal clearance. DS-1040 caused a substantial dose-dependent and time-dependent decrease in TAFIa activity and in 50% clot lysis time. The levels of D-dimer, indicative of endogenous fibrinolysis, increased in some individuals following DS-1040 treatment. No effects of DS-1040 on coagulation parameters or platelet aggregation were observed. Conclusions The novel fibrinolysis-enhancing agent DS-1040 has favorable pharmacokinetic/pharmacodynamic properties and a favorable safety profile, warranting further clinical development.

Nilotinib (Tasigna), a highly selective and potent BCR-ABL tyrosine kinase inhibitor (TKI), is administered orally and has pH-dependent aqueous solubility, with lower dissolution at higher pH. This study evaluated the effect of esomeprazole on the pharmacokinetics of nilotinib in healthy participants. Twenty-two participants (6 women, 16 men, mean age of 44.9 +/- 12.9 years) were enrolled to receive nilotinib as a single oral 400-mg dose on days 1 and 13 and esomeprazole as 40 mg once daily on days 8 to 13. Serial blood samples were collected up to 72 hours after nilotinib dosing, and nilotinib serum concentrations were determined by a validated liquid chromatography/tandem mass spectrometry assay. Gastric pH was also monitored in all participants. When coadministered with esomeprazole, nilotinib C(max) was decreased by 27% and AUC(0-infinity) decreased by 34%. Nilotinib t(max) was prolonged from 4.0 to 6.0 hours, but t(1/2) was not altered. Mean gastric pH was 1.0 +/- 0.5 at baseline and increased to 2.79 +/- 2.50, 3.98 +/- 2.27, 5.30 +/- 1.70, 5.38 +/- 1.26, and 5.31 +/- 1.42 at predose and 1, 2, 3, and 4 hours after the fifth esomeprazole dose, respectively. These results suggested a modest reduction in the rate and extent of nilotinib absorption by esomeprazole. Nilotinib is a TKI that may be used concurrently with esomeprazole or other proton pump inhibitors.