Rationale and Design of BeatNF2 Trial: A Clinical Trial to Assess the Efficacy and Safety of Bevacizumab in Patients with Neurofibromatosis Type 2 Related Vestibular Schwannoma.

Neurofibromatosis type 2 (NF2) causes bilateral vestibular schwannomas (VSs), leading to deafness. VS is treated by surgery or radiation, but neither treatments prevent hearing loss. Bevacizumab was found to be effective in suppressing the tumor's growth and may help to improve hearing. We are conducting a randomized, double-blind, multicenter clinical trial to verify the efficacy and safety of bevacizumab in NF2-related VS. The primary objective is to evaluate the efficacy of bevacizumab in improving hearing in the affected ear. One of the secondary objectives is to evaluate bevacizumab's efficacy in rechallenge treatment in relapsed cases. Sixty patients will randomly receive either bevacizumab or a placebo and will be clinically observed for 48 weeks in the initial intervention phase. In the first half (24 weeks), they will receive either 5 mg/kg of bevacizumab or a placebo drug. In the second half, all patients will receive 5 mg/kg of bevacizumab. If hearing function deteriorated in a patient who had shown improvement during the first phase, a rechallenge dose with bevacizumab would be offered.

Delta-like 1 homolog (DLK1) as a possible therapeutic target and its application to radioimmunotherapy using 125I-labelled anti-DLK1 antibody in lung cancer models (HOT1801 and FIGHT004).

OBJECTIVES: Delta-like 1 homolog (DLK1) is a non-canonical Notch ligand known to be expressed in several cancers but whose role in lung cancer is not yet fully understood. We sought to confirm DLK1 expression in small-cell lung cancer (SCLC) and non-small-cell lung cancer (NSCLC), and to examine DLK1's clinical significance. Furthermore, we examined the possible utility of DLK1 as a novel target in radioimmunotherapy (RIT). METHODS: We retrospectively assessed the correlation between clinical features and DLK1 expression by immunohistochemistry in resected specimens from 112 patients with SCLC and 101 patients with NSCLC. Moreover, we performed cell and animal experiments, and examined the possibility of RIT targeting DLK1 in SCLC using iodine-125 (125I) -labeled anti-DLK1 antibody, knowing that 125I can be replaced with the alpha-particle-emitter astatine-211 (211At). RESULTS: In SCLC and NSCLC, 20.5 % (23/112) and 16.8 % (17/101) of patients (respectively) had DLK1-positive tumors. In NSCLC, DLK1 expression was associated with recurrence-free survival (P < 0.01) but not with overall survival. In SCLC, there was no association between DLK1 expression and survival. In addition, 125I-labeled anti-DLK1 antibody specifically targeted DLK1 on human SCLC tumor cell lines. Furthermore, 125I-labeled anti-DLK1 antibody was incorporated into tumor tissue in a mouse model. CONCLUSION: A proportion of SCLC and NSCLC exhibits DLK1 expression. As a clinical feature, DLK1 expression could be a promising prognostic factor for recurrence in patients with resected NSCLC. In addition, DLK1 could serve as a new therapeutic target, including RIT, as suggested by our pilot study using a radiolabeled anti-DLK1 antibody in SCLC.

Effects of Child-Pugh B Cirrhosis on Pharmacokinetics of Tofogliflozin, a New Sodium-Glucose Co-Transporter (SGLT2) Inhibitor.

BACKGROUND: Tofogliflozin is a highly selective sodium-glucose co-transporter 2 (SGLT2) inhibitor. A mass balance study with combinations of microdoses revealed that tofogliflozin has high oral bioavailability (97.5%) and that tofogliflozin in circulation is eliminated primarily by metabolic pathways, with the liver playing a prominent role in elimination. OBJECTIVES: This study aimed to evaluate the effect of moderate hepatic impairment on the pharmacokinetics of tofogliflozin and on the pharmacodynamics (urinary glucose excretion [UGE]). METHODS: In an open-label, parallel-group study, 17 subjects (9 with moderate hepatic impairment [Child-Pugh Class B, score 7-9] and 8 healthy) received a single oral dose of 40 mg tofogliflozin. Plasma and urine concentrations of tofogliflozin were determined. Accumulated UGE, adverse events, and physiological and laboratory test data were monitored. RESULTS: Geometric mean ratio (GMR; geometric mean value for subjects with moderate hepatic impairment / geometric mean value for healthy subjects) of Cmax was 1.47 and GMR of AUCinf was 1.70. Moderate hepatic impairment had only a little effect on tmax and CLR but it prolonged MRT. The levels of cumulative UGE were similar between the 2 groups. No clinically significant adverse events, laboratory test values, or physiological test values were observed in any subject. CONCLUSIONS: Moderate hepatic impairment increased Cmax and AUCinf of tofogliflozin by 47% and 70%, respectively. This increase in tofogliflozin exposure did not increase UGE in hepatically impaired subjects. A single oral dose of 40 mg tofogliflozin was well tolerated, supporting dose adjustment is unnecessary even in moderately hepatically impaired subjects.

Determination of the Kinetic Parameters for 123I Uptake by the Thyroid, Thyroid Weights, and Thyroid Volumes in Present-day Healthy Japanese Volunteers.

The purpose of this study was to evaluate the kinetic parameters that determine the uptake rate of radioiodide in the thyroid over 24 h after administration and to estimate thyroid volumes/masses of present-day Japanese. Methods: We determined the thyroid uptake rate of I in healthy male Japanese after oral administration (4.5-8.0 MBq) without iodine restriction. Masses of thyroid glands were collected in 2012-2016 during autopsies of 7,651 male and 3,331 female subjects. Volumes of thyroid glands were estimated by ultrasonography and magnetic resonance imaging in 52 male subjects. Results: The thyroid uptake rate of I for 24 h was 16.1 ± 5.4%. Kinetic model analysis was conducted to obtain the clearances (L h) for thyroid uptake and urinary excretion of I (0.499 ± 0.258 and 2.10 ± 0.39 L h, respectively). The masses of thyroid glands were on average 19.8 g (95% confidence interval of 18.3-19.5 g) and 15.5 g (95% confidence interval of 14.7-16.2 g) in male and female subjects aged 19-52 y, respectively. Volumes of thyroid glands estimated by ultrasonography and magnetic resonance imaging were 17.5 ± 5.2 and 14.2 ± 5.3 mL, respectively. In healthy Japanese, there has been no significant change for at least 50 y in the thyroid uptake of radioiodide over 24 h or in its kinetic parameters. These Japanese-specific kinetic parameters will allow quantitative estimation of the radiation exposure from the Fukushima accident and its variance during the individual's evacuation from or stay in Fukushima.

Comparison of pharmacokinetics of newly discovered aromatase inhibitors by a cassette microdosing approach in healthy Japanese subjects.

The aim of the present study is to investigate the pharmacokinetics of our newly developed aromatase inhibitors (cetrozole and TMD-322) in healthy subjects by a cassette microdose strategy. A cocktail of cetrozole and TMD-322 was administered intravenously or orally (1.98 µg for each drug) to six healthy volunteers in a crossover fashion. Anastrozole (1.98 µg) was also included in the oral cocktail. Total body clearance and bioavailability were 12.1 ± 7.1 mL/min/kg and 34.9 ± 32.3% for cetrozole, and 16.8 ± 3.5 mL/min/kg and 18.4 ± 12.2% for TMD-322, respectively. The area under the plasma concentration-time curves of cetrozole and TMD-322 after oral administration was markedly lower than that of anastrozole because of their high hepatic clearance. Two subjects out of six exhibited 4- and 17-fold larger exposure of cetrozole than the others following intravenous and oral administration, respectively. Such variation was not observed for TMD-322 and anastrozole. Extensive metabolism of cetrozole and TMD-322 was observed in the CYP2C19 expression system among the test CYP isoforms (CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4). We report the first clinical investigation of our aromatase inhibitors by a cassette microdose strategy in healthy Japanese subjects. This strategy offers an optional approach for candidate selection as a phase zero study in drug development.

An Assessment of the Oral Bioavailability of Three Ca-Channel Blockers Using a Cassette-Microdose Study: A New Strategy for Streamlining Oral Drug Development.

A cassette-microdose (MD) clinical study was performed to demonstrate its usefulness for identifying the most promising compound for oral use. Three Ca-channel blockers (nifedipine, nicardipine, and diltiazem) were chosen as model drugs. In the MD clinical study, a cassette-dose method was employed in which three model drugs were administered simultaneously. Both intravenous (i.v.) and oral (p.o.) administration studies were conducted to calculate the oral bioavailability (BA). For comparison, p.o. studies with therapeutic dose (ThD) levels were also performed. In all studies, blood concentrations of each drug were successfully determined using liquid chromatography-mass spectrometry with the lower limit of quantification of 0.2-2.0 pg/mL. Oral BA of nifedipine in the MD study was approximately 50% and in the same range with that obtained in the ThD study, whereas other two drugs showed significantly lower BA in the MD study, indicating a dose-dependent absorption. In addition, compared with the ThD study, absorption of nicardipine was delayed in the MD study. As a result, nifedipine was considered to be most promising for oral use. In conclusion, a cassette-MD clinical study is of advantage for oral drug development that enables to identify the candidate having desired properties for oral use.

Dosing time-dependent effect of raloxifene on plasma plasminogen activator inhibitor-1 concentrations in post-menopausal women with osteoporosis.

Raloxifene, a selective oestrogen receptor modulator commonly used for the treatment of post-menopausal osteoporosis, affects the coagulation and fibrinolytic systems and consequently increases the risk of venous thromboembolism. Because both the coagulation and fibrinolytic systems exhibit circadian rhythms, the aim of the present study was to investigate the effects of dosing time of raloxifene on markers of coagulation and fibrinolysis, as well as on markers of bone metabolism. Thirty-nine post-menopausal patients with osteoporosis were randomly allocated to two groups: one received 60 mg raloxifene once daily in the morning, whereas the other received 60 mg raloxifene once daily in the evening, for 12 months. In both groups, the activity of coagulation Factors IX and XII was increased significantly after 12 months treatment compared with baseline. The activity of coagulation Factors II and V and levels of markers of bone metabolism (i.e. bone alkaline phosphatase and tartrate-resistant acid phosphatase 5b) decreased in both groups. The changes in these markers did not differ between the two groups. In contrast, the plasma concentration of plasminogen activator inhibitor (PAI)-1 increased in the group receiving the morning dose (mean change 40.9%; 95% confidence interval (CI) 9.4, 72.5), but not in the groups receiving the evening dose (mean change -0.3%; 95% CI -31.5, 30.9); these percentage changes differed significantly (P < 0.05). Because an elevated concentration of PAI-1 is known to be associated with the risk of venous thromboembolism, the findings of the present study suggest that the dosing time of raloxifene influences its safety. Further larger-scale studies are needed to determine the clinical usefulness of chronotherapy with raloxifene.

The effect of carboxylesterase 1 (CES1) polymorphisms on the pharmacokinetics of oseltamivir in humans.

PURPOSE: The aim of this study was to examine whether carboxylesterase 1 (CES1A) genetic polymorphisms affect the pharmacokinetics of oseltamivir. METHODS: Thirty healthy Japanese male and female subjects ranging in age from 20 to 36 years voluntarily participated in this study. These subjects were administered a single 75-mg dose of oseltamivir (Tamiflu®), and blood samples were collected predose and up to 24 h after oseltamivir administration. Oseltamivir and its active metabolite, oseltamivir carboxylate, were measured by liquid chromatography-time of flight/mass spectrometry with solid-phase extraction. The CES1A diplotypes [a combination of haplotypes A (CES1A3-CES1A1), B (CES1A2-CES1A1), C (CES1A3-CES1A1variant), and D (CES1A2-CES1A1variant)] were determined by PCR-restriction fragment length polymorphism analysis and direct sequencing. RESULTS: All subjects completed the study according to the protocol, and no clinically meaningful adverse events were attributable to the administration of oseltamivir. No significant differences in the pharmacokinetic parameters of oseltamivir and oseltamivir carboxylate were observed according to CES1A genotype. In one subject, the peak concentration and area under the concentration-time curve (AUC) of oseltamivir were approximately tenfold higher than the mean values of the other subjects. CONCLUSIONS: In our study, the known interindividual variability in oseltamivir metabolism was not explained by CES1A genetic polymorphisms, but are likely the result of other factors. While one subject was found to exhibit an approximate tenfold higher AUC than the other subjects, no abnormal behaviors were associated with the increased oseltamivir plasma concentrations. Further studies are required to reveal the cause of individual differences in CES1A metabolism and the abnormal behavioral effects of oseltamivir.

Pharmacokinetic interaction study of sulphasalazine in healthy subjects and the impact of curcumin as an in vivo inhibitor of BCRP.

BACKGROUND AND PURPOSE An ATP-binding cassette (ABC) transporter, breast cancer resistance protein (BCRP)/ABCG2, limits oral bioavailability of sulphasalazine. Here we examined the effect of curcumin, the principal curcuminoid of turmeric, on oral bioavailability of microdoses and therapeutic doses of sulphasalazine in humans. EXPERIMENTAL APPROACH Effects of curcumin were measured on the ATP-dependent sulphasalazine uptake by hBCRP-expressing membrane vesicles and on oral bioavailability of sulphasalazine in wild-type and Bcrp(-/-) mice. Eight healthy Japanese subjects received an oral dose of sulphasalazine suspension (100 µg) or tablets (2 g) alone or after curcumin tablets (2 g). Uptake of sulphasalazine was studied in HEK293 cells transfected with the influx transporter (OATP)2B1. KEY RESULTS Curcumin was a potent hBCRP inhibitor in vitro (K(i) 0.70 ± 0.41 µM). Curcumin increased the area under the curve (AUC)(0-8) of plasma sulphasalazine eightfold in wild-type mice at 300 and 400 mg·kg(-1), but not in Bcrp(-/-) mice. Curcumin increased AUC(0-24) of plasma sulphasalazine 2.0-fold at microdoses and 3.2-fold at therapeutic doses in humans. Non-linearity of the dose-exposure relationship was observed between microdoses and therapeutic doses of sulphasalazine. Sulphasalazine was a substrate for OATP2B1 (K(m) 1.7 ± 0.3 µM). Its linear index (dose/K(m)) at the therapeutic dose was high and may saturate OATP2B1. CONCLUSIONS AND IMPLICATIONS Curcumin can be used to investigate effects of BCRP on oral bioavailability of drugs in humans. Besides the limited dissolution, OATP2B1 saturation is a possible mechanism underlying non-linearity in the dose-exposure relationship of sulphasalazine.

Effect of milk on the pharmacokinetics of oseltamivir in healthy volunteers.

We previously showed that oseltamivir, a prodrug of the influenza virus neuraminidase inhibitor Ro 64-0802, is a substrate of proton-coupled oligopeptide transporter (PEPT1), and its intestinal absorption in rats is markedly inhibited by administration with milk. To investigate the importance of PEPT1 for oseltamivir absorption in humans, and the characteristics of the drug-milk interaction, a crossover clinical study was conducted in healthy volunteers, who received 75 mg of oseltamivir with 400 mL of water or milk. Milk significantly reduced the maximum plasma concentration (C(max) ) and the area under the plasma concentration-time curve from 0 to 2 h (AUC(0-2) ) of both oseltamivir and Ro 64-0802 (oseltamivir, 68.9% and 34.5%; Ro 64-0802, 69.5% and 14.2%, respectively, vs. water), but had no significant effect on the apparent terminal half-life (t(1/2) ) or AUC(0-∞) . Urinary recovery of oseltamivir and Ro 64-0802 was significantly reduced to 77.5% of the control by milk. The early reduction of oseltamivir absorption might be through the PEPT1 inhibition by milk peptides. However, the extent of interaction in humans was limited as compared with that in rats, possibly because of species difference in the PEPT1 expression and its contribution. This might be the first report suggesting the clinical drug-food interaction via PEPT1.

Functional regions of organic cation/carnitine transporter OCTN2 (SLC22A5): roles in carnitine recognition.

The organic cation/carnitine transporter OCTN2 transports carnitine in a sodium-dependent manner, whereas it transports organic cations sodium-independently. To elucidate the functional domain in OCTN2, we constructed chimeric proteins of human OCTN2 (hOCTN2) and mouse OCTN3 (mOCTN3) and introduced mutations at several amino acids conserved among human, rat and mouse OCTN2. We found that transmembrane domains (TMD) 1-7 are responsible for organic cation transport and for sodium dependence in carnitine transport. Within TMD1-7, Q180 and Q207 of hOCTN2 are the critical amino acids for the sodium dependence, and double mutation of Q180 and Q207 resulted in minimal change in transport activity when sodium was removed from the uptake medium. We propose that sodium-dependent affinity for carnitine is dependent on sodium recognition by these critical amino acids in hOCTN2, whereas carnitine transport by OCTN2 requires functional linkage between TMD1-7 and TMD11.

Acetyl-L-carnitine permeability across the blood-brain barrier and involvement of carnitine transporter OCTN2.

OCTN2 (SLC22A5), an organic cation/carnitine transporter, is widely distributed throughout the body, including the brain. In the present study, the involvement of OCTN2 in acetyl-L-carnitine (ALCAR) permeation across the blood-brain barrier (BBB) was examined using a microdialysis method in mouse. OCTN2 function was examined by comparison of wild-type mice with jvs mice, which express defective OCTN2 and are considered a model for primary systemic carnitine deficiency. Zero-net-flux method analysis indicated higher in vivo recovery of ALCAR and lower physiological ALCAR concentration in thalamus extracellular fluid (ECF) in jvs mice compared with wild-type mice. Externally added ALCAR showed significantly slower initial uptake across the BBB in jvs mouse. These results indicated that OCTN2 is functionally involved in ALCAR transfer across the BBB. Total radioactivity in ECF after i.v. administration of radiolabelled ALCAR remained constant for the rest of the experimental period. Accordingly, our results indicate that ALCAR is transported from blood to brain ECF by OCTN2 at least in part, and its concentration in brain ECF is regulated by other events such as protein binding and anabolic reactions in the brain, as well as by transport across the BBB.

Studies on functional sites of organic cation/carnitine transporter OCTN2 (SLC22A5) using a Ser467Cys mutant protein.

The organic cation/carnitine transporter OCTN2 mediates transport of carnitine and organic cations in Na(+)-dependent and Na(+)-independent manners, respectively. However, the mechanism of molecular recognition of different substrates has not been clarified yet. We previously found a single amino acid change in OCTN2, Ser467Cys (S467C), in the Japanese population and observed a decreased carnitine transport but unchanged organic cation transport compared with wild type. Therefore, we conducted detailed kinetic and functional analyses of the substrate recognition sites of wild-type and S467C-mutant OCTN2. The K(m) value for carnitine of S467C-mutant was increased about 15-fold over that of the wild type. Mutual inhibition kinetics of carnitine and tetraethylammonium (TEA) were not completely competitive, suggesting that the binding sites are very close to each other, but not identical. Several organic anions such as valproate, as well as organic cations, significantly inhibited carnitine and TEA uptake by OCTN2, and valproate showed Na(+)-dependent inhibition of OCTN2-mediated TEA uptake. The Na(+)-activation kinetics of the S467C mutant was similar to that of the wild type. Furthermore, a significant decrease of the TEA uptake-inhibitory potency of valproate was observed in S467C-mutant OCTN2. These observations suggest that the decrease in affinity of S467C-mutant OCTN2 for carnitine was caused by functional alteration of the anion (carboxyl moiety of carnitine) recognition site located in trans-membrane domain 11, which is closely related to the Na(+)-binding site, on OCTN2 protein. These results demonstrate that OCTN2 has functional sites for carnitine and Na(+) and that the carnitine-binding site is involved, in part, in the recognition of organic cations.