Effect of Food on the Pharmacokinetic and Pharmacodynamic Profiles of Hetrombopag in Healthy Volunteers

PurposeHetrombopag, a novel, oral small molecule thrombopoietin receptor agonist, exhibits an obvious thrombocytopoietic effect with good safety. Hetrombopag is currently under clinical development for the treatment of chronic idiopathic thrombocytopenic purpura (ITP). The objectives of this study were to assess the effect of high-fat and high-calorie food on the pharmacokinetic and pharmacodynamic (PK/PD) profiles of hetrombopag in healthy volunteers.MethodsAn independent, single-dose, open-label, randomized-sequence, crossover trial was conducted. Healthy volunteers received hetrombopag 7.5-mg tablets in the fasted state or with a high-fat, high-calorie breakfast. The effects of the high-fat and high-calorie food on the PK/PD profiles of hetrombopag were evaluated by using a noncompartmental analysis and a semi-physiological model.FindingsTwelve Chinese healthy volunteers were enrolled. Mean plasma AUC_0–t and C_max decreased by 98.7% and 95.0%, respectively, when hetrombopag was administered with high-fat and high-calorie food. The semi-physiological PK/PD model analysis showed that the absorption rate constant at the first absorption site was almost halved at the fed condition. The change in platelet counts in the fed condition was not sufficiently as sensitive as that in the fasted condition.ImplicationsHigh-fat and high-calorie food were associated with significantly reduced systemic exposure and platelet count sensitivity. Thus, hetrombopag should be taken in a fasted state to avoid the impact of food on bioavailability and platelet counts. ClinicalTrials.gov identifier: NCT02409394.     

Pharmacokinetic analysis

Pharmacokinetic analysis is an experimentally determined theory of how a drug behaves when in vivo. Volume of distribution, clearance and terminal half-life are defined. Compartmental modelling is introduced and some relevant graphs are described in this article. Applications of this theory in anaesthesia are considered.     

Physiologically based pharmacokinetic modelling of oxycodone drug–drug interactions

Oxycodone is an opioid analgesic with several pharmacologically active metabolites and relatively narrow therapeutic index. Cytochrome P450 (CYP) 3A4 and CYP2D6 play major roles in the metabolism of oxycodone and its metabolites. Thus, inhibition and induction of these enzymes may result in substantial changes in the exposure of both oxycodone and its metabolites. In this study, a physiologically based pharmacokinetic (PBPK) model was built using GastroPlus™ software for oxycodone, two primary metabolites (noroxycodone, oxymorphone) and one secondary metabolite (noroxymorphone). The model was built based on literature and in house in vitro and in silico data. The model was refined and verified against literature clinical data after oxycodone administration in the absence of drug–drug interactions (DDI). The model was further challenged with simulations of oxycodone DDI with CYP3A4 inhibitors ketoconazole and itraconazole, CYP3A4 inducer rifampicin and CYP2D6 inhibitor quinidine. The magnitude of DDI (AUC ratio) was predicted within 1.5-fold error for oxycodone, within 1.8-fold and 1.3–4.5-fold error for the primary metabolites noroxycodone and oxymorphone, respectively, and within 1.4–4.5-fold error for the secondary metabolite noroxymorphone, when compared to the mean observed AUC ratios. This work demonstrated the capability of PBPK model to simulate DDI of the administered compounds and the formed metabolites of both DDI victim and perpetrator. However, the predictions for the formed metabolites tend to be associated with higher uncertainty than the predictions for the administered compound. The oxycodone model provides a tool for forecasting oxycodone DDI with other CYP3A4 and CYP2D6 DDI perpetrators that may be co-administered with oxycodone.     

Pharmacokinetics and Pharmacodynamics of a Proposed Pegfilgrastim Biosimilar MSB11455 Versus the Reference Pegfilgrastim Neulasta in Healthy Subjects: A Randomized,Double-blind Trial

PurposeMSB11455 is a proposed biosimilar to the reference pegfilgrastim (Neulasta®). This pivotal equivalence study (NCT03251248) assessed the pharmacokinetic and pharmacodynamic equivalence of MSB11455 to the reference product.MethodsThis 2-way, 2-sequence, group-sequential, crossover study was conducted in healthy subjects. Subjects received a single subcutaneous dose of MSB11455 or the reference product (both 6 mg/0.6 mL) on Day 1 of each study period. Pharmacokinetic and pharmacodynamic (absolute neutrophil count; ANC) samples were taken predose and up to day 16 post-dose. Non-compartmental parameters were calculated. Immunogenicity samples were taken pre-dose and up to day 84 after the first dose. Safety was assessed throughout the study.FindingsA total of 292 subjects were randomized to therapy and treated; 244 received both treatments. For all primary pharmacokinetic and pharmacodynamic parameters, 90% repeated confidence intervals of geometric means ratio of MSB11455 to the reference product were within the pre-defined equivalence range (80.00%–125.00%) for AUC_0-∞ (96.59–112.82); AUC_0–last (97.29–113.96), C_max (97.13–114.99), maximum observed effect on ANC (98.74–102.39), and area under the effect–time curve from time zero to time to last quantifiable concentration (97.30–100.23). Safety, tolerability, and immunogenicity were comparable between treatments. No filgrastim-specific neutralizing antibodies were detected with either treatment sequence.ImplicationsPharmacokinetic and pharmacodynamic equivalence of MSB11455 and the reference product was shown, with comparable immunogenicity, safety, and tolerability between treatments. The study supports the biosimilarity of MSB11455 to the reference product. ClinicalTrials.gov identifier: NCT03251248.     

Pharmacokinetic and Glucodynamic Responses of Ultra Rapid Lispro vs Lispro Across a Clinically Relevant Range of Subcutaneous Doses in Healthy Subjects

PurposeUltra rapid lispro (URLi) is a novel insulin lispro formulation developed to more closely match physiological insulin secretion and improve postprandial glucose control. This study compared the pharmacokinetic and glucodynamic parameters of URLi and Lispro (Humalog®) at 3 dose levels in healthy subjects.MethodsThis randomized, 6-period, subject- and investigator-blind, crossover study included 42 healthy subjects. At each period, subjects received a single subcutaneous dose of 7, 15, or 30 U of URLi or Lispro followed by a 10-h automated euglycemic clamp. Insulin lispro and blood glucose concentrations were measured.FindingsAcross all 3 doses, insulin lispro appeared in the serum 2–5 min faster, and exposure was 6- to 8-fold greater in the first 15 min, with URLi versus Lispro. Exposure beyond 3 h postdose was 45%–52% lower, and duration of exposure was 67–86 min shorter with URLi versus Lispro for all dose levels. Onset of insulin action was 7–9 min faster and insulin action was ~3-fold greater in the first 30 min with URLi versus Lispro across the dose levels. Insulin action beyond 4 h was reduced by 32%–45%, and duration of action was reduced by 47–67 min, with URLi versus Lispro for all 3 dose levels. Overall exposure and total glucose infused were similar between URLi and Lispro at each dose level. Dose proportionality was observed for maximum and overall exposure after URLi. Less than dose-proportional increases in maximum and total glucose infused were observed and were similar for both URLi and Lispro.ImplicationsURLi exhibited ultra-rapid pharmacokinetic and glucodynamic parameters across all 3 dose levels studied and exhibited dose-proportional increases in exposure in healthy subjects. ClinicalTrials.gov identifier: NCT03286751.     

Comparative pharmacokinetics and tissue distribution of cryptotanshinone,tanshinone IIA,dihydrotanshinone I,and tanshinone I after oral administration of pure tanshinones and liposoluble extract of Salvia miltiorrhiza to rats

Salvia miltiorrhiza is one of the most commonly used traditional Chinese medicines in the treatment of cardiovascular and cerebrovascular diseases. Cryptotanshinone (CTS), tanshinone IIA (Tan IIA), dihydrotanshinone I (diTan I), and tanshinone I (Tan I) are the main active compounds in the liposoluble extract of Salvia miltiorrhiza. The differences in the pharmacokinetic and tissue distribution behaviors of the four tanshinones after oral administration of the liposoluble extract of Salvia miltiorrhiza and pure compounds are not clear. This study aims to compare the pharmacokinetics and tissue distribution of the four tanshinones after oral administration of pure tanshinone monomers and the liposoluble extract of Salvia miltiorrhiza. An ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) analysis method was developed for the determination of the four tanshinones. The results showed that the AUC and C_max of tanshinones in rats receiving the extract of Salvia miltiorrhiza were significantly increased compared with those receiving the pure tanshinones. In the tissue distribution experiments, the AUC of the four tanshinones in the extract was much greater than the AUC of the monomers in the lung, heart, kidney, liver, and brain, and the coexisting constituents particularly promoted the distribution of tanshinones into tissues that the drug cannot sufficiently penetrate. These findings suggested that the coexisting constituents in the liposoluble extract of Salvia miltiorrhiza play an important role in the alteration of plasma concentration and tissue distribution of the four tanshinones. Understanding these differences could be of significance for the development and application of Salvia miltiorrhiza extract and tanshinone components.     

Quantifying breast milk intake by term and preterm infants for input into paediatric physiologically based pharmacokinetic models

Despite the many benefits of breast milk, mothers taking medication are often uncertain about the risks of drug exposure to their infants and decide not to breastfeed. Physiologically based pharmacokinetic models can contribute to drug‐in‐milk safety assessments by predicting the infant exposure and subsequently, risk for toxic effects that would result from continuous breastfeeding. This review aimed to quantify breast milk intake feeding parameters in term and preterm infants using literature data for input into paediatric physiologically based pharmacokinetic models designed for drug‐in‐milk risk assessment. Ovid MEDLINE and Embase were searched up to July 2, 2019. Key study reference lists and grey literature were reviewed. Title, abstract and full text were screened in nonduplicate. Daily weight‐normalized human milk intake (WHMI) and feeding frequency by age were extracted. The review process retrieved 52 studies. A nonlinear regression equation was constructed to describe the WHMI of exclusively breastfed term infants from birth to 1 year of age. In all cases, preterm infants fed with similar feeding parameters to term infants on a weight‐normalized basis. Maximum WHMI was 152.6 ml/kg/day at 19.7 days, and weighted mean feeding frequency was 7.7 feeds/day. Existing methods for approximating breast milk intake were refined by using a comprehensive set of literature data to describe WHMI and feeding frequency. Milk feeding parameters were quantified for preterm infants, a vulnerable population at risk for high drug exposure and toxic effects. A high‐risk period of exposure at 2–4 weeks of age was identified and can inform future drug‐in‐milk risk assessments.     

Phage therapy: What factors shape phage pharmacokinetics and bioavailability? Systematic and critical review

Bacteriophages are not forgotten viruses anymore: scientists and practitioners seek to understand phage pharmacokinetics in animals and humans, investigating bacteriophages as therapeutics, nanocarriers or microbiome components. This review provides a comprehensive overview of factors that determine phage circulation, penetration, and clearance, and that in consequence determine phage applicability for medicine. It makes use of experimental data collected by the phage community so far (PubMed 1924-2016, including non-English reports), combining elements of critical and systematic review. This study covers phage ability to enter a system by various routes of administration, how (and if) the phage may access various tissues and organs, and finally what mechanisms determine the courses of phage clearance. The systematic review method was applied to analyze (i) phage survival in the gut (gut transit) and (ii) phage ability to enter the mammalian system by many administration routes. Aspects that have not yet been covered by a sufficient number of reports for mathematical analysis, as well as mechanisms underlying trends, are discussed in the form of a critical review. In spite of the extraordinary diversity of bacteriophages and possible phage applications, the analysis revealed that phage morphology, phage specificity, phage dose, presence of sensitive bacteria or the characteristics of treated individuals (age, taxonomy) may affect phage bioavailability in animals and humans. However, once phages successfully enter the body, they reach most organs, including the central nervous system. Bacteriophages are cleared mainly by the immune system: innate immunity removes phages even when no specific response to bacteriophages has yet developed.