Pharmacokinetic study of saxagliptin in healthy Chinese subjects.

BACKGROUND AND OBJECTIVES: The pharmacokinetics of some medications may be affected by differences in race and ethnicity, which can lead to suboptimal outcomes. The present study was conducted to assess the single- and multiple-dose pharmacokinetics of saxagliptin in healthy Chinese subjects living in China. METHODS: This was an open-label, 9-day study conducted at the Drug Clinical Trial Center, Peking University Third Hospital, Beijing, China. Sixteen healthy Chinese subjects of both sexes between 21 and 33 years of age were administered saxagliptin 5 mg orally on day 1, then once daily on days 3-7. Pharmacokinetic variables for saxagliptin (primary outcome) and its active metabolite, 5-hydroxy saxagliptin (secondary outcome), after single and multiple oral doses of saxagliptin were assessed. Safety was also assessed. RESULTS: Saxagliptin was absorbed rapidly (median time to reach maximum concentration [t(max)]: 0.5 and 1 hour on days 1 and 7, respectively), and its pharmacologically active metabolite, 5-hydroxy saxagliptin, appeared in plasma (median t(max): 1.0 and 1.5 hours, respectively). Plasma exposure to 5-hydroxy saxagliptin was approximately 2- to 3-fold higher than exposure to saxagliptin. Plasma concentration-time profiles for saxagliptin and 5-hydroxy saxagliptin were similar on days 1 and 7, with no evidence of drug accumulation on repeated dosing. The elimination half-lives (t(½)) for saxagliptin and 5-hydroxy saxagliptin were approximately 3 and 4 hours, respectively, with renal excretion as the primary route of elimination. After single and multiple dosing, 54.48% and 52.60%, respectively, of the administered saxagliptin dose was recovered in urine as unchanged drug or 5-hydroxy saxagliptin. Saxagliptin was generally well tolerated. Six (37.5%) subjects experienced an adverse event (AE). All AEs were mild in intensity and judged by the investigator as not related to the study medication. There were no deaths, serious AEs, discontinuations due to AEs, or other clinically significant AEs during this study. CONCLUSION: Saxagliptin 5 mg (single dose and once-daily doses for 5 days) was generally well tolerated; the pharmacokinetics of saxagliptin and 5-hydroxy saxagliptin in healthy Chinese subjects were consistent with previous assessments in the saxagliptin clinical development program. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT00770302.

Evaluation of the effect of dapagliflozin on cardiac repolarization: a thorough QT/QTc study.

INTRODUCTION: Dapagliflozin is a first-in-class sodium-glucose transporter 2 (SGLT2) inhibitor under investigation for the treatment of type 2 diabetes mellitus. A thorough QTc study was conducted, according to International Conference on Harmonization E14 guidelines, to characterize the effect of dapagliflozin on cardiac repolarization. METHODS: The present study was a double-blind, four-period, placebo-controlled crossover study at a single-center inpatient clinical pharmacology unit. The study enrolled 50 healthy men who were randomized to receive sequences of single doses of dapagliflozin 150 mg, dapagliflozin 20 mg, moxifloxacin 400 mg, and placebo. The sequences were randomized based on the Williams design for a cross-over study to reduce the "carryover" effects from drug-to-drug even with sufficient washout periods. Digital 12-lead electrocardiograms were recorded at nine time points over 24 hours in each period. QT intervals were corrected for heart rate using a study-specific correction factor (QTcX) and Fridericia's formula. RESULTS: For dapagliflozin, the upper bound of the one-sided 95% confidence interval (CI) for time-matched, placebo-subtracted, baseline adjusted QTc intervals (ΔΔQTc) was <10 ms. ΔΔQTc was independent of dapagliflozin concentrations. No QTc thresholds >450 ms or QTc increases >30 ms were observed. Moxifloxacin increased the mean QTcX interval by 7.7 ms (lower bound 90% CI, 6.2 ms) over 1-4 hours after dosing, confirming assay sensitivity. CONCLUSION: Dapagliflozin, at supratherapeutic doses, does not have a clinically significant effect on the QT interval in healthy subjects.

Antihypertensive efficacy of candesartan-lisinopril in combination vs. up-titration of lisinopril: the AMAZE trials.

The AMAZE (A Multicenter Trial Using Atacand and Zestril vs. Zestril to Evaluate the Effects on Lowering Blood Pressure) program included two identical studies sponsored by AstraZeneca LP. The oral form of candesartan is candesartan cilexetil; for simplicity, the term "candesartan" is used throughout this manuscript. Two identical multicenter, randomized, double-blind studies were performed to determine if addition of the angiotensin receptor blocker candesartan was more effective in lowering blood pressure than up-titration of lisinopril. Hypertensive patients (N=1,096) who were uncontrolled on lisinopril 20 mg daily were randomized (1:1) to receive either 8 weeks of high-dose lisinopril (40 mg) or the addition of candesartan (16 mg) for 2 weeks followed by 32 mg for 6 weeks. Study 1 (n=538) demonstrated decreases in trough sitting systolic/diastolic blood pressures at Week 8 by 6.2/5.9 mm Hg, respectively, for the lisinopril up-titration treatment group and by 11.6/8.3 mm Hg, respectively, for the lisinopril plus candesartan treatment group (p<0.01 in comparing both blood pressures reductions between the two treatment groups). Corresponding results for Study 2 (n=558) are reductions of 8.7/6.2 mm Hg and 9.5/7.4 mm Hg, respectively, for each of the two treatment groups. For Study 2, comparisons of systolic/diastolic blood pressures between the two treatment groups were not statistically significantly different (p=0.51/p=0.08, respectively). Post hoc pooled analysis (N=1,096) demonstrated a slightly greater blood pressure reduction with lisinopril plus candesartan compared with lisinopril (3.1/1.7 mm Hg). A 95% confidence interval limit for the difference in least squares mean change from baseline in systolic blood pressure between the two treatment groups is -4.8 to -1.5 and is -2.8 to -0.7 in mm Hg for diastolic blood pressure. The blood pressure control rates (<140/<90 mm Hg) were 42.7% and 36.9%, respectively. Both treatment regimens were well tolerated in all groups. In conclusion, for hypertensive patients not controlled by lisinopril 20 mg once daily, addition of candesartan (32 mg once daily) or doubling the dose of lisinopril provides safe, additional reduction of blood pressure.