Hepatic Adaptation to Therapeutic Doses of Acetaminophen: An Exploratory Study in Healthy Individuals.

PURPOSE: Acetaminophen (APAP) has hepatotoxic potential when overdosed. Recent studies have reported serum alanine aminotransferase (ALT) elevations that resolve spontaneously with continued use of the drug, referred to as adaptation, in several individuals receiving therapeutic doses of APAP. However, the clinical significance of these ALT elevations remains unclear. This study was performed to investigate the incidence and characteristics of hepatic adaptation to therapeutic doses of APAP in healthy individuals. METHODS: In a randomized, single-blind, placebo-controlled study, 242 healthy Japanese individuals were enrolled. Each person received 3 g/d of APAP (n = 202) or placebo (n = 40) for 28 days. All study participants underwent analysis of genetic polymorphisms of CYP2E1 and UGT1A1; measurements of plasma APAP concentration and urine metabolites (glucuronide, sulfate, cysteine, and mercapturate); liver function monitoring, including ALT, microRNA-122, and high-mobility group box 1. Individuals with ALT levels remaining below the upper limit of normal (ULN; 40 U/L) during the study period were defined as tolerant and those with ALT elevations above the ULN as susceptible. Susceptible individuals who developed ALT elevations exceeding 2 × ULN discontinued use of the study drug for tolerability consideration. Susceptible individuals who had ALT elevations that decreased toward the ULN spontaneously with continued use of the study drug were classified as adaptation. FINDINGS: In the APAP group, 129 individuals (66%) were classified as tolerant and 65 (34%) as susceptible. Among 65 susceptible individuals, 12 (18%) discontinued use of APAP because of ALT elevations (>2 × ULN), whereas 53 (82%) completed 28-day APAP dosing. Thirty of 65 susceptible individuals (46%) had adaptation within 28 days. In the placebo group, no individuals was withdrawn from the study because of elevated ALT levels, 33 individuals (89%) were classified as tolerant, and 4 (11%) were classified as susceptible. None had clinical signs of liver injury. ALT level correlated significantly with microRNA-122 but not with high-mobility group box 1. No association was found between plasma APAP concentrations and ALT levels. Urinary excretion of APAP mercapturate was higher in susceptible than in tolerant individuals (P = 0.018, Wilcoxon or Kruskal-Wallis test). The frequency of homozygotes and compound heterozygotes for UGT1A1∗28 and UGT1A1∗6 (∗28/∗28, ∗6/∗6, and ∗6/∗28) was higher in susceptible than in tolerant individuals (13.9% vs 3.9%; P = 0.011, χ2 test). IMPLICATIONS: These findings indicate that in healthy individuals, APAP at a therapeutic dose can cause transient and self-limiting ALT elevation, reflecting subclinical hepatocellular damage, and these ALT elevations may be associated with the disposition of APAP metabolites and genetic factors. UMIN-CTR identifier: UMIN000019607.

Pharmacokinetics and Safety After a Single Dose of Imarikiren in Subjects with Renal or Hepatic Impairment.

BACKGROUND AND OBJECTIVE: Imarikiren hydrochloride (TAK-272; SCO-272) is a novel direct renin inhibitor. The objective of this study was to determine the effects of renal impairment (RI) or hepatic impairment (HI) on the pharmacokinetics and safety of imarikiren. METHODS: This phase I, open-label, parallel-group comparative study evaluated the pharmacokinetics and safety of a single 40 mg oral dose of imarikiren in RI [mild, moderate, severe, or end-stage renal disease (ESRD), and on hemodialysis] or HI (mild or moderate) subjects compared with subjects with normal renal or hepatic function. RESULTS: Following administration of a single 40 mg oral imarikiren dose, the geometric mean imarikiren area under the plasma concentration-time curve from time zero to infinity (AUC∞) and maximum observed plasma concentration (Cmax) in subjects with mild, moderate, and severe RI (including non-hemodialysis and ESRD), and hemodialysis subjects compared with normal renal function subjects were approximately 0.5-, 1.2-, 2.7-, and 1.8-fold, respectively, for AUC∞; and approximately 0.6-, 0.8-, 2.1-, and 1.4-fold, respectively, for Cmax. The mean fraction of excretion of imarikiren in dialysate was ~ 3% during the 4 h dialysis period. The geometric mean imarikiren AUC∞ and Cmax in mild and moderate HI subjects compared with normal hepatic function subjects were approximately 1.0- and 1.4-fold, respectively, for AUC∞, and approximately 0.9- and 1.3-fold, respectively, for Cmax. No deaths or serious adverse events were observed; all adverse events were mild or moderate in intensity. CONCLUSIONS: RI and HI are associated with limited changes in imarikiren pharmacokinetics. Imarikiren was safe and well-tolerated, regardless of the severity of RI or HI. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02367872.

A Double-Blind, Randomized, Crossover Comparative Study for Evaluating the Clinical Safety of Ephedrine Alkaloids-Free Ephedra Herb Extract (EFE).

Ephedra Herb is an important crude drug; it is used in various Traditional Japanese Medicine (Kampo) formulations. Its significant pharmacological effects have been believed to be attributed to ephedrine and pseudoephedrine, which sometimes induce adverse effects. On the other hand, it has been reported that some of these pharmacological effects are not dependent on ephedrine or pseudoephedrine. Ephedrine alkaloids-free Ephedra Herb extract has been newly developed. It has been reported to have analgesic, anti-influenza, and antimetastatic effects. This clinical trial was aimed at verifying the noninferiority of EFE's safety compared to that of Ephedra Herb extract (EHE) in humans. This was a single-institution, double-blinded, randomized, two-drug, two-stage, crossover comparative study. Twelve healthy male subjects were equally and randomly allocated into two groups: prior administration of EFE (EFE-P) and prior administration of EHE (EHE-P). In Stage 1, EFE and EHE were orally administered to the EFE-P and EHE-P groups, respectively, for six days. After a 4-week washout period, Stage 2 was initiated wherein the subjects were given a study drug different from Stage 1 study drug for six days. Eleven adverse events with a causal relationship to the study drugs (EHE: 8; EFE: 3) were noted; all events were mild in severity. With regard to the incidence of adverse events, EHE and EFE administration, respectively, accounted for 4 cases (out of 12 subjects, similarly below) and 1 case of increased pulse rate (p=0.32) and 3 cases and 1 case of insomnia (p=0.59). Further, there was one case of hot flashes (p=1.00) due to EFE administration and one case of dysuria (p=1.00) due to EHE administration. There were no significant differences in the incidences of adverse events between EHE administration and EFE administration. Therefore, we concluded that EFE is not inferior to EHE in terms of safety.

Lack of effect of favipiravir, a novel antiviral agent, on QT interval in healthy Japanese adults.

OBJECTIVE: A thorough QT study of favipiravir, a novel antiviral agent, was conducted using a randomized, doubleblind, 4-group, 4-period crossover, placebo-and positive-controlled (open-label moxifloxacin) design. MATERIALS AND METHODS: 56 healthy Japanese adults of both sexes received single oral doses of favipiravir 1,200 and 2,400 mg (Avigan® Tablets, Toyama Chemical Co., Ltd.), moxifloxacin 400 mg, and a placebo. QT intervals after these treatments were measured under blinded conditions. The primary endpoint was the time-matched, placebo-adjusted change in corrected QT intervals using the Fridericia method (QTcF) from predose for favipiravir or moxifloxacin (ΔΔQTcF). RESULTS: Lower bounds of the two-sided 90% confidence interval of ΔΔQTcF values for moxifloxacin exceeded 3 msec at all time points, and the maximum value was 14.0 (11.8-16.1, 90% confidence interval) msec at 3 hours after administration. Similarly, maximum ΔΔQTcF values for favipiravir were 0.833 (-1.33-3.00) msec at 3 hours after administration of 1,200 mg, and 0.500 (-1.88-2.88) msec at 6 hours after administration of 2,400 mg. Calculation of the sample size using the ΔΔQTcF value of moxifloxacin indicated that 25 subjects would be sufficient for detection at a power of 90% or higher, which meets the criteria for assuring assay sensitivity. CONCLUSIONS: It is possible to use a smaller number of subjects in thorough QT studies in Japan than in Europe and the US utilizing moxifloxacin as a positive control. There were no detectable effects of favipiravir on the QT/QTc interval.

Evaluation of the safety, tolerability, and pharmacokinetics of a single bolus injection of daptomycin in healthy Japanese subjects.

UNLABELLED: This was a phase I double-blind, randomized, placebo-controlled, 2-period, single-dose, crossover study in healthy Japanese subjects to evaluate the safety, tolerability, and pharmacokinetics of a single bolus injection of daptomycin. Twenty healthy subjects were randomized; 16 received a single intravenous (IV) administration of 6 mg/kg of daptomycin and 4 received a single intravenous administration of placebo (0.9% sodium chloride) by either bolus injection (10 s) or infusion (30 min) following an overnight fast in Periods 1 or 2. There was a minimum 5-day washout period from the administration in Period 1 to the administration in Period 2. Administration of a single bolus injection of daptomycin 6 mg/kg was generally well tolerated. The geometric mean ratios (GMRs) (90% confidence intervals [CIs]) for AUC0-∞, AUC0-24 h, Cmax, and C24 h of daptomycin in plasma following bolus injection over 10 s relative to IV infusion over 30 min were 1.01 (1.00, 1.03), 1.02 (1.00, 1.03), 1.50 (1.41, 1.60) and 1.05 (1.02, 1.08), respectively. Because no existing studies of this nature were available, Cmax following daptomycin 6 mg/kg/10 s multiple-dose bolus injections was simulated. It was estimated at 178 µg/mL (upper limit) and was expected to be equal to or less than the confirmed Cmax in Japanese or non-Japanese healthy subjects following single- or multiple-dose IV infusion over 30 min. From the results of this study, daptomycin multiple-dose bolus injections over 10 s are expected well tolerated and to have similar Cmax values as IV infusion over 30 min, thus offering potential clinical benefit. TRIAL REGISTRATION: Because this was a phase I trial in healthy subjects, the trial was not registered.