Takehiko Kawanishi

A first-in-human phase 1 study of ACE910, a novel factor VIII-mimetic bispecific antibody, in healthy subjects.

ACE910 is a recombinant humanized bispecific antibody that binds to activated factor IX and factor X and mimics the cofactor function of factor VIII (FVIII). This first-in-human study examined the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of ACE910 in healthy male adults. A total of 40 Japanese and 24 white subjects were randomized to receive a single subcutaneous injection of ACE910 (Japanese: 0.001, 0.01, 0.1, 0.3, or 1 mg/kg; white: 0.1, 0.3, or 1 mg/kg; n = 6 per dose group) or placebo (n = 2 per dose group). ACE910 exhibited a linear PK profile and had a half-life of ∼4 to 5 weeks. In FVIII-neutralized plasma, ACE910 shortened activated partial thromboplastin time and increased peak height of thrombin generation in a dose-dependent manner. All adverse events were nonserious and did not lead to any subjects withdrawal. Neither clinical findings nor laboratory abnormalities indicating hypercoagulability were observed. Two of 48 subjects receiving ACE910 (1 Japanese and 1 white) were positive for anti-ACE910 antibodies (anti-drug antibodies [ADAs]). One subject tested positive for ADAs both before and after ACE910 administration, whereas the other became ADA positive after receiving ACE910. The PK and PD profiles of ACE910 were similar in healthy Japanese and white subjects and suggest that ACE910 will be an effective and convenient prophylactic treatment of hemophilia A. This trial was registered at www.clinicaltrials.jp as #JapicCTI-121934.

Method development and validation of the simultaneous determination of a novel topoisomerase 1 inhibitor, the prodrug, and the active metabolite in human plasma using column-switching LC-MS/MS, and its application in a clinical trial.

A robust and sensitive method using liquid chromatography-tandem mass spectrometry was developed and validated for the simultaneous determination of a novel topoisomerase 1 inhibitor CH0793076 (3076), the prodrug CH4556300 (TP300), and the active metabolite CH0793011 (3011) in human plasma. All plasma analyzed with this method was acidified with 1M HCl and 46% citric acid solution in a ratio of 100:10:1 (v:v:v) to avoid the pH-based degradation of TP300 and to shift the equilibria of 3076 and 3011 between the lactone and carboxylate forms towards the lactone forms. After the plasma proteins were precipitated with methanol:acetonitrile:HCl 1M (50:50:1, v:v:v) containing stable isotopic internal standards, the analytes were trapped on an Xterra MS C18 column (10×2.1 mm i.d., 5 μm) and separated on a Gemini C18 column (50×2.0 mm i.d., 5 μm) using column-switching liquid chromatography. Electrospray ionization in the positive-ion mode and multiple reaction monitoring were used to quantify the analytes with transitions m/z 587.2>441.2 for TP300, 459.1>415.2 for 3076, and 475.1>361.1 for 3011. The inter- and intra-day precisions were below 12%, and the accuracy was between -16% and 16% at the lower limit of quantitation (LLOQ) and between -11% and 14% at the other quality controls. The LLOQs of TP300, 3076, and 3011 were 0.8, 0.04, and 0.04 ng/mL, respectively. The validated method was successfully applied to clinical sample analysis and incurred sample reanalysis was also conducted.

Novel procedure for the preparation of 1α,3β-dihydroxy-2β-tritiated steroidal compounds

Abstract A novel procedure for the preparation of 1α,3β-dihydroxy-2β-tritiated steroidal compounds by the reduction of the α-epoxide with sodium horotritiide in diglyme at 80 C is described.

Erratum to: Application of Modeling and Simulation to a Long-Term Clinical Trial: A Direct Comparison of Simulated Data and Data Actually Observed in Japanese Osteoporosis Patients Following 3-Year Ibandronate Treatment

Ibandronate, a nitrogen-containing bisphosphonate, is a bone resorption inhibitor widely used to prevent and treat osteoporosis. To optimize the design for a long-term clinical study of ibandronate, modeling and simulation (MS (2) perform MS and (3) conduct the long-term clinical study. Application of this procedure to various other treatment agents will establish the usefulness of M&S for long-term clinical studies and bring further efficiencies to drug development.

Nonlinear intestinal pharmacokinetics of mitemcinal, the first acid-resistant non-peptide motilin receptor agonist, in rats

The objective was to investigate the mechanism of nonlinear pharmacokinetics of mitemcinal, the first acid-resistant non-peptide motilin agonist, in rats. Super-proportional increases of the cumulative rates of radioactivity excreted into bile and urine following oral administration of [3H]-mitemcinal suggested nonlinear absorption of mitemcinal in rats. To evaluate the fraction dose absorbed (Fa) and intestinal availability (Fg), [3H]-mitemcinal was orally administrated to rats, and tritium radioactivity and unchanged mitemcinal concentration were determined in the portal blood. Fa values for 0.2 mg/kg1, 0.5 mg/kg, and 5.0 mg/kg dose groups were 0.314, 0.353, and 0.569, respectively. Corresponding Fg values were 0.243, 0.296, and 0.513, respectively. In Caco-2 experiments, the permeation of [3H]-mitemcinal in the secretory direction was larger than in the absorptive direction and was inhibited by P-glycoprotein (P-gp) substrate digoxin. The results indicate that the saturation of P-gp-mediated membrane permeation and intestinal metabolism causes the nonlinear pharmacokinetics of mitemcinal in rats.

The pharmacokinetics of ceftriaxone based on population pharmacokinetics and the prediction of efficacy in Japanese adults

SummaryObjective: By using a population pharmacokinetic analysis method, we predicted the efficacy of Ceftriaxone (CTRX) based on the pharmacokinetics of CTRX in Japanese adults and the sensitivity of infective organisms to CTRX in 2004. In addition, we clarified the difference in efficacy between once-a-day administration and twice-a-day administration. Methods: The population pharmacokinetic analysis was based on the serum concentrations of CTRX already published by NONMEM. The possible effect of body weight and age on the pharmacokinetics of CTRX was examined using a model which incorporated the change of a specific protein-binding ratio of CTRX. A Monte Carlo simulation was conducted based on the population pharmacokinetic parameters obtained by this analysis, and thereby the time above MIC (TAM) was determined from the MIC values of CTRX administered once at 0.5, 1, and 2 g and twice at 1 g. The efficacy ratio was predicted from the TAM thus obtained. Results: Because the time course of serum concentration of CTRX in adult subjects was fitted to a 2-compartment model and both body weight and age were not incorporated as the covariate, the dosing method by which a fixed amount of CTRX is administered to patients has been thought to be adequate. Based on the efficacy ratio estimated from the MIC of CTRX, we have predicted that the once-a-day administration of CTRX even at 0.5g is effective on various infecting organisms.

Population pharmacokinetic-pharmacodynamic modelling and simulation of neutropenia induced by TP300, a novel topoisomerase I inhibitor.

TP300 is a novel topoisomerase I inhibitor with neutropenia as a significant toxicity. We developed and evaluated a pharmacokinetic–pharmacodynamic (PK‐PD) model, using data from Phase I and II trials to predict neutrophil decrease in patients treated with TP300.

Indications for a ceftriaxone dosing regimen in Japanese paediatric patients using population pharmacokinetic/pharmacodynamic analysis and simulation

Objectives  The objective of this study was to build a ceftriaxone population pharmacokinetic model for Japanese paediatric patients and to examine the dosing regimen of ceftriaxone based on pharmacokinetic/pharmacodynamic (PK/PD) analysis.

MALDI mass spectrometry imaging of erlotinib administered in combination with bevacizumab in xenograft mice bearing B901L, EGFR-mutated NSCLC cells

Combination therapy of erlotinib plus bevacizumab improves progression-free survival of patients with epidermal growth factor receptor–mutated (EGFR-mutated) advanced non–small-cell lung cancer (NSCLC) compared with erlotinib alone. Although improved delivery and distribution of erlotinib to tumours as a result of the normalization of microvessels by bevacizumab is thought to be one of the underlying mechanisms, there is insufficient supporting evidence. B901L cells derived from EGFR-mutated NSCLC were subcutaneously implanted into mice, and mice were treated with bevacizumab or human IgG followed by treatment with erlotinib. The distribution of erlotinib in their tumours at different times after erlotinib administration was analysed by matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI). We also analysed the distribution of erlotinib metabolites and the distribution of erlotinib in tumours refractory to erlotinib, which were established by long-term treatment with erlotinib. We found that erlotinib was broadly diffused in the tumours from B901L-implanted xenograft mice, independently of bevacizumab treatment. We also found that erlotinib metabolites were co-localized with erlotinib and that erlotinib in erlotinib-refractory tumours was broadly distributed throughout the tumour tissue. Multivariate imaging approaches using MALDI MSI as applied in this study are of great value for pharmacokinetic studies in drug development.

Relative and Absolute Bioavailability Study of Emicizumab to Bridge Drug Products and Subcutaneous Injection Sites in Healthy Volunteers

Emicizumab (ACE910) is a bispecific antibody that is a novel, subcutaneously injectable treatment for patients with hemophilia A. This study assessed the relative bioavailability of emicizumab between old and new drug products (DPs) and among 3 commonly used subcutaneous injection sites (abdomen, upper arm, and thigh), together with its absolute bioavailability in healthy volunteers. Forty‐eight healthy volunteers were randomized into 4 groups to receive a single subcutaneous injection of 1 mg/kg with the old or new DP, and another 12 volunteers each received a single, 90‐minute, intravenous infusion of 0.25 mg/kg with the new DP. Similar pharmacokinetic profiles were observed between the DPs, with geometric mean ratios of 1.199 (90% confidence interval [CI] 1.060‐1.355) for the maximum plasma concentration and 1.083 (90% CI 0.920‐1.275) for area under the plasma concentration‐time curve extrapolated to infinity. The geometric mean ratios of maximum plasma concentration and area under the plasma concentration‐time curve extrapolated to infinity for upper arm versus abdomen were 0.823 (90% CI 0.718‐0.943) and 0.926 (90% CI 0.814‐1.053), respectively, and those for thigh versus abdomen were 1.168 (90% CI 1.030‐1.324) and 1.073 (90% CI 0.969‐1.189), respectively. Absolute bioavailability ranged from 80.4% to 93.1%. These results suggested that no emicizumab dose adjustment would be needed when switching the DPs or injecting to different sites interchangeably and that emicizumab injected subcutaneously is highly bioavailable.