Thorough QT/QTc study to evaluate the effect of a single supratherapeutic dose of islatravir on QTc interval prolongation in healthy adults.

Islatravir is a deoxynucleoside analog being developed for the treatment of HIV-1 infection. Clinical studies are being conducted to evaluate islatravir, administered in combination with other antiretroviral therapies, at doses of 0.25 mg once daily and 2 mg once weekly. In multiple previous clinical studies, islatravir was generally well tolerated, with no clear trend in cardiac adverse events. A trial was conducted to evaluate the effect of islatravir on cardiac repolarization. A randomized, double-blind, active- and placebo-controlled phase 1 trial was conducted, in which a single dose of islatravir 0.75 mg, islatravir 240 mg (supratherapeutic dose), moxifloxacin 400 mg (active control), or placebo was administered. Continuous 12-lead electrocardiogram monitoring was performed before dosing through 24 hours after dosing. QT interval measurements were collected, and safety and pharmacokinetics were evaluated. Sixty-three participants were enrolled, and 59 completed the study. Fridericia's QT correction for heart rate was inadequate; therefore, a population-specific correction was applied (QTcP). The placebo-corrected change from baseline in QTcP (ΔΔQTcP) interval at the observed geometric mean maximum plasma concentration associated with islatravir 0.75 mg and islatravir 240 mg was <10 ms at all time points. Assay sensitivity was confirmed because the use of moxifloxacin 400 mg led to a ΔΔQTcP >10 ms. The pharmacokinetic profile of islatravir was consistent with that of previous studies, and islatravir was generally well tolerated. Results from the current trial suggest that single doses of islatravir as high as 240 mg do not lead to QTc interval prolongation.

Effects of 13-Hour Hyperglucagonemia on Energy Expenditure and Hepatic Glucose Production in Humans.

Glucagon (GCG) acutely stimulates energy expenditure (EE) and hepatic glucose production (HGP) in humans, but whether these effects persist during hyperglucagonemia of longer duration is unclear. Using a prospective, randomized, single-blind, crossover study design, we therefore measured EE and rates of glucose appearance (glucose RA) during three separate infusion protocols in healthy lean males: A) 10-h overnight GCG infusion (6 ng/[kg × min]) followed by 3-h infusion of GCG, octreotide (OCT), and insulin (INS) for basal replacement; B) overnight saline (SAL) infusion followed by GCG/OCT/INS infusion; and C) overnight SAL infusion followed by SAL/OCT/INS infusion. Sleep EE, measured at 6 to 7 h of the overnight infusion, was increased 65-70 kcal/24 h in A compared with B and C. During the 3-h infusion, mean resting EE remained significantly increased in A versus C by ∼50 kcal/24 h; in B, resting EE increased with a statistical trend but was not significantly greater than in C. Glucose RA increased to comparable levels in A and B. We conclude that in healthy lean males, stimulation of EE and HGP is sustained during hyperglucagonemia of longer duration when insulin secretion is inhibited. The increase in EE at the present GCG dose was of marginal clinical significance.

Effect of metal-cation antacids on the pharmacokinetics of 1200 mg raltegravir.

OBJECTIVES: Raltegravir is a human immunodeficiency virus (HIV)-1 integrase strand transfer inhibitor currently marketed at a dose of 400 mg twice daily (BID). Raltegravir for once-daily regimen (QD) at a dose of 1200 mg is under development. The effect of calcium carbonate and magnesium/aluminium hydroxide antacids on the pharmacokinetics of a 1200 mg dose of raltegravir was assessed in this study. METHODS: An open-label, four-period, four-treatment, fixed-sequence study in 20 HIV-infected patients was performed. Patients needed to be on raltegravir as part of a stable treatment regimen for HIV, and upon entry into the trial received 5 days of 1200 mg raltegravir as pretreatment, before they entered the four-period study: 1200 mg of raltegravir alone (period 1), calcium carbonate antacid as TUMS® Ultra Strength (US) 1000 and 1200 mg raltegravir given concomitantly (Period 2), magnesium/aluminium hydroxide antacid as 20 ml MAALOX® Maximum Strength substitute MS given 12 h after administration of 1200 mg raltegravir (period 3), and calcium carbonate antacid as TUMS® US 1000 given 12 h after administration of 1200 mg raltegravir (period 4). Patients received their dose of 1200 mg QD raltegravir during the intervals between periods to re-establish steady state. AUC0-24 , C24 , Cmax and Tmax were calculated from the individual plasma concentrations of 1200 mg QD raltegravir after administration alone or with a calcium carbonate antacid or with a staggered dose of a calcium carbonate antacid or magnesium/aluminium hydroxide antacid. Adverse events, in addition to laboratory safety tests (haematology, serum chemistry and urinalysis), 12-lead electrocardiograms and vital signs were assessed. KEY FINDINGS: All treatments were well tolerated in the study. Metal-cation antacids variably affected the pharmacokinetics of 1200 mg QD raltegravir. When calcium carbonate antacid was given with 1200 mg raltegravir concomitantly, the geometric mean ratio (GMR) and its associated 90% confidence interval (90% CI) for AUC0-24 , Cmax and C24 h were 0.28 (0.24, 0.32), 0.26 (0.21, 0.32) and 0.52 (0.45, 0.61), respectively. When calcium carbonate antacid and magnesium/aluminium hydroxide were given 12 h after raltegravir 1200 mg QD dosing, the GMR (90% CI) values for AUC0-24 and Cmax were 0.90 (0.80, 1.03), 0.98 (0.81, 1.17), and 0.86 (0.73, 1.03), 0.86 (0.65, 1.15), respectively. However, significant reduction in the trough concentrations of raltegravir was observed: C24 h 0.43 (0.36, 0.51) in the presence of calcium carbonate antacids and 0.42 (0.34, 0.52) in presence of magnesium/aluminium hydroxide, respectively. CONCLUSIONS: Overall, the use of metal-cation antacids with 1200 mg QD raltegravir is not recommended.

Effect of telcagepant on spontaneous ischemia in cardiovascular patients in a randomized study.

OBJECTIVE: The primary purpose of the study was to explore the safety and tolerability of telcagepant in patients with stable coronary artery disease. BACKGROUND: Triptans are effective acute anti-migraine drugs whose vasoconstrictive effects limit their use in patients at risk for adverse cardiovascular events. Telcagepant, a calcitonin gene-related peptide receptor antagonist, is being developed for the acute treatment of migraine. Antagonism of calcitonin gene-related peptide, which does not appear to cause vasoconstriction, may allow for treatment of migraine in patients with coronary artery disease. METHODS: In this randomized, double-blind, placebo-controlled, crossover study, patients with documented stable coronary artery disease were assigned to 1 of 2 treatment sequences: telcagepant then placebo, or placebo then telcagepant. In each treatment period, patients received 2 doses of telcagepant 300-mg or placebo 2 hours apart. They remained in the research center for 24 hours after receiving the first dose of each period, during which time continuous 12-lead ambulatory electrocardiographic (Holter) monitoring was performed. RESULTS: Twenty-eight patients were enrolled; all patients completed the study and were included in all analyses. Telcagepant was generally well tolerated. No laboratory or serious adverse experiences were reported, and no patient discontinued due to an adverse experience. There were no consistent treatment-related changes in laboratory, vital signs or electrocardiogram safety parameters. Three patients (2 after receiving placebo and 1 after receiving telcagepant) experienced ST segment depression during the study; none of these patients reported chest pain. CONCLUSIONS: Two doses of 300-mg telcagepant, administered 2 hours apart, did not appear to exacerbate spontaneous ischemia and were generally well tolerated in a small cohort of patients with stable coronary artery disease. Results of this study support further evaluation of telcagepant in patients with stable coronary artery disease.