Relationship between drug lag and factors associated with clinical trials in Japan.

WHAT IS KNOWN AND OBJECTIVE: Drug lag is a major public concern in Japan. During the development of new drugs, some factors related to clinical trials in the marketing application package, such as trial design and the number of trials, can affect drug approval. The aim of this study was to determine whether those clinical trial factors were associated with drug lag in Japan. METHODS: We investigated new drug applications for new molecular entities that were approved in Japan between April 2009 and March 2012. We collected information on clinical trials in the marketing application package from review reports. RESULTS AND DISCUSSION: We constructed a multiple regression model to predict drug lag using the review period, use of foreign clinical trial data, the number of confirmatory trials, the design of the pivotal trial, failures of confirmatory trials and the death rate (n = 59). No use of foreign trial data was significantly associated with a longer drug lag (84% increase; 95% confidence interval [CI], 1·03-3·29). Compared to the open-label, one-armed design, drugs that underwent pivotal trials of placebo-controlled superiority, active-controlled superiority and active-controlled non-inferiority designs had a significantly shorter drug lag (74% decrease, 95% CI: 0·08-0·83; 74% decrease, 95% CI: 0·07-0·99; and 85% decrease, 95% CI: 0·04-0·58, respectively). WHAT IS NEW AND CONCLUSION: Our findings suggest that new drug application packages that do not use data from foreign clinical trials and that involve pivotal trials of open-label, one-armed design contribute to drug lag in Japan. To reduce this lag, improved strategies for the development of new drugs should be identified.

Pharmacokinetics of the amidine prodrug of a novel oral anticoagulant factor VIIa inhibitor (AS1924269-00) in rats.

AS1924269-00 is a promising orally applicable anticoagulant that inhibits FVIIa but has very low oral absorption. Therefore, in this study, we aimed to develop a prodrug of AS1924269-00, which possesses a carbamate-added amidine functional group, with high membrane permeability. We investigated the pharmacokinetics of the carbamate-type prodrug of AS1924269-00 in rats. The Caco-2 cell monolayer was used as an in vitro model and in parallel an artificial membrane permeability assay (PAMPA) was performed to examine the transport mechanisms of the prodrug. The bioavailability of the active form was determined to be only 0.3% in rats, but the oral absorption of the prodrug was markedly improved, and its bioavailability was 36%. Our in vivo result was consistent with the finding that compared to AS1924269-00, the prodrug showed favorable permeability in Caco-2 cells and PAMPA. We introduced carbamate into the amidine functional group of the FVIIa inhibitor, which possesses the amidine backbone, and converted it to a prodrug using carboxylic acid ethyl ester. This novel prodrug had favorable absorption and membrane permeability in vivo and in vitro. Thus, we suggest a clinical application of the carbamate-added amidine prodrug of the FVIIa inhibitor.

Characterization of in vitro biotransformation of the new oral anticoagulants, the factor VIIa inhibitors AS1927819-00 and AS1932804-00.

We recently developed a prodrug (AS1932804-00, CMP) of the novel FVIIa inhibitor AS1924269-00, which possesses a carbamate amidine backbone. In addition, we developed another type of prodrug (AS1927819-00, OXP) with an oxime amidine backbone. In this study, we investigated the efficiency of conversion of these novel FVIIa prodrugs to their active forms by evaluating the production of the active form in vitro by using microsomes, mitochondria, and cryopreserved hepatocytes, and compared it with the in vivo conversion mechanisms of the prodrugs (oxime amidine vs. carbamate amidine). We observed that OXP and CMP showed improved oral absorption, and the efficiency of conversion of CMP to the active form was higher than that of OXP. The in vivo rate of conversion of OXP to its active form was low in rats, and compared to liver microsomes and mitochondria, cryopreserved hepatocytes supplemented with serum and coenzymes were an appropriate metabolic test tool. On the other hand, the efficiency of conversion of CMP to its active from could be appropriately evaluated using small intestinal microsomes. The development of a prodrug can be optimized when information about the stability of carboxylic acid esters in the presence of serum esterases, membrane permeability of intermediate forms, and differential tissue specificity to metabolic activities for carbamate and oxime backbones of amidine can be obtained.

Observation of a large reaction cross section in the drip-line nucleus 22C.

Reaction cross sections (sigma(R)) for 19C, 20C and the drip-line nucleus 22C on a liquid hydrogen target have been measured at around 40A MeV by a transmission method. A large enhancement of sigma(R) for 22C compared to those for neighboring C isotopes was observed. Using a finite-range Glauber calculation under an optical-limit approximation the rms matter radius of 22C was deduced to be 5.4+/-0.9 fm. It does not follow the systematic behavior of radii in carbon isotopes with N < or = 14, suggesting a neutron halo. It was found by an analysis based on a few-body Glauber calculation that the two-valence neutrons in 22C preferentially occupy the 1s(1/2) orbital.

Effects of molecular crowding environment on the acquisition of toxic properties of wild-type SOD1.

BACKGROUND: Mutants of Cu,Zn-superoxide dismutase (SOD1) exhibit cytotoxicity such as aggregation and pro-oxidation after denaturation, which is thought to be involved in the pathogenesis of amyotrophic lateral sclerosis (ALS). In the present study, we investigated the possibility of the acquisition of toxic properties for wild-type SOD1 (WT) in the demetalated (apo) form after denaturation. METHODS: Denaturation and subsequent pro-oxidant activity of SOD1 were confirmed by circular dichroism (CD) spectroscopy and fluorescence assay, respectively. The aggregation of SOD1 was investigated by native polyacrylamide gel electrophoresis (PAGE). Crowding environment was prepared by the addition of polyethylene glycol (PEG) into buffer solution. RESULTS: The structural stability of SOD1 is reduced by demetallation. Nevertheless, high temperatures around 45 °C are required to induce denaturation of apo-WT. The generated denaturated apo-WT exhibits pro-oxidant activity after the rebinding of Cu2+. In molecular crowding environment mimicked by PEG, apo-WT is found to exhibit denaturation even at physiological temperature. The denatured WT in molecular crowding environment has both the activities of pro-oxidation and aggregation. The acquisition of the pro-oxidant activity is accelerated for H43R, which is an ALS-related mutant, in molecular crowding environment. CONCLUSIONS: Apo-WT acquires the toxic properties at physiological temperature when subjected to molecular crowding environment. Molecular crowding environment also accelerates the induction of the toxicity for H43R. GENERAL SIGNIFICANCE: Molecular crowding environment in living cells becomes an instability factor inducing denaturation and subsequent toxicity for SOD1. Apo-WT also has the toxic properties in molecular crowding environment, which can be related to the pathogenesis of ALS.

Autoimmunity associated with TGF-beta1-deficiency in mice is dependent on MHC class II antigen expression.

The progressive inflammatory process found in transforming growth factor beta1 (TGF-beta1)-deficient mice is associated with several manifestations of autoimmunity, including circulating antibodies to nuclear antigens, immune complex deposition, and increased expression of both class I and class II major histocompatibility complex (MHC) antigens. The contribution of MHC class II antigens to the genesis of this phenotype has been determined by crossing the TGF-beta1-null [TGF-beta1(-/-)] genotype into the MHC class II-deficient [MHC-II(-/-)] background. Mice homozygous for both the TGF-beta1 null allele and the class II null allele [TGF-beta1(-/-);MHC-II(-/-)] are without evidence of inflammatory infiltrates, circulating autoantibodies, or glomerular immune complex deposits. Instead, these animals exhibit extensive extramedullary hematopoiesis with progressive splenomegaly and adenopathy, surviving only slightly longer than TGF-beta1(-/-);MHC-II(+/+) mice. The role of CD4+ T cells, which are also absent in MHC class II-deficient mice, is directly demonstrated through the administration of anti-CD4 monoclonal antibodies in class II-positive, TGF-beta1(-/-) mice. The observed reduction in inflammation and improved survival emphasize the significance of CD4+ cells in the pathogenesis of the autoimmune process and suggest that the additional absence of class II antigens in TGF-beta1(-/-);MHC-II(-/-) mice may contribute to their extreme myeloid metaplasia. Thus, MHC class II antigens are essential for the expression of autoimmunity in TGF-beta1-deficient mice, and normally may cooperate with TGF-beta1 to regulate hematopoiesis.

The peptide hormone xenin induces gallbladder contractions in conscious dogs.

Xenin is a 25-amino acid peptide isolated from human gastric mucosa. The biological activities of xenin include modulating intestinal motility and affecting exocrine pancreatic secretion and gastric acid secretion. The physiological effect of xenin on the gastrointestinal tract, however, is incomplete. The objective of this study is to investigate the effects of xenin on the gastrointestinal tract motility of conscious dogs. Gastrointestinal tract and gallbladder contractions were monitored by chronically implanted force transducers. Synthetic xenin was injected intravenously during the interdigestive state with or without pretreatment with cholinergic blockers. The effects of xenin following cholecystectomy and truncal vagotomy were also investigated. Xenin induced gallbladder and jejunal contractions, although a dose-dependent response was shown only with gallbladder contractions. These effects were inhibited by pretreatment with cholinergic blockers, but were not enhanced by truncal vagotomy. The jejunal contractions were completely inhibited by cholecystectomy. The only direct effect of xenin in terms of gastrointestinal motility was to induce gallbladder contractions in conscious dogs. The neural pathway mediating xenin's action was cholinergic, but not the vagal. This novel finding indicates a new role of xenin.

Change in the structure and function of lectin by photodissociation of NO.

We have shown here that the structure and sugar-binding activity of lectin can be changed by the photodissociation of NO. Intramolecular S-S bonds are photogenerated from SNO in the protein, which can be used to photo-control the structure and function of proteins.

Ghrelin does not stimulate gastrointestinal motility and gastric emptying: an experimental study of conscious dogs.

Ghrelin is a peptide that was discovered in endocrine cells of the stomach. However, its action in regulating the fasted and fed motor activity of the digestive tract is not fully understood. In the present study, we examined the effects of an intravenous (i.v.) injection of canine ghrelin on the physiological fasted and fed motor activities in the stomach, duodenum, jejunum and colon of freely moving conscious dogs. An i.v. injection of canine ghrelin released growth hormone in a dose-dependent manner; however, it did not stimulate the motor activity of the digestive tract in either the fasted or the fed state. Moreover, an i.v. injection of high-dose canine ghrelin significantly reduced the motility index in the gastric body in the fasted state. Ghrelin did not accelerate gastric emptying, either. These results differ from previous reports dealing with rodents. It is significant that such results were obtained in research with dogs, which are larger animals.

Phosphorylation of DNA topoisomerase I is increased during the response of mammalian cells to mitogenic stimuli.

DNA topoisomerase I is phosphorylated after mitogenic stimulation of 3T3-L1 mouse fibroblasts by 12-O-tetradecanoylphorbol 13-acetate (TPA), a phorbol ester tumor promoter. In vivo labeling with [32P]orthophosphate and immunoprecipitation with an anti-DNA topoisomerase I antibody has demonstrated an increase in the phosphorylation of DNA topoisomerase I in Swiss/3T3 mouse fibroblasts treated with epidermal growth factor (EGF) and H35 rat hepatoma cells treated with insulin. The only phosphorylated form of DNA topoisomerase I observed was the 100-kDa protein Digestion of DNA topoisomerase I with trypsin revealed two phosphopeptides. In addition, VT-1, a non-responsive genetic variant of 3T3-L1, and the DNA topoisomerase I inhibitor camptothecin were used to further study TPA-induced DNA topoisomerase I phosphorylation. Our results indicate that the phosphorylation of DNA topoisomerase I may be an ubiquitous response of cultured mammalian cells to mitogenic agents, even in the absence of DNA replication.

Phase II study of irinotecan and etoposide in patients with metastatic non-small-cell lung cancer.

PURPOSE: To determine the effects of irinotecan (CPT-11) given in combination with etoposide (VP-16) in metastatic non-small-cell lung cancer (NSCLC), to evaluate response and survival rates, and to determine the qualitative and quantitative toxicities of the combination chemotherapy. PATIENTS AND METHODS: Sixty-one metastatic NSCLC patients received concurrent administration of CPT-11 and VP-16 for 3 days with recombinant human granulocyte colony-stimulating factor (rhG-CSF) support. RESULTS: Fifty-nine patients were assessable for response and all 61 patients were assessable for toxicity and survival. Fifty-six patients were treated with two or more courses of chemotherapy. Thirteen patients achieved a partial response (PR), 36 showed no change (NC), and 10 showed progressive disease (PD). The overall response rate was 21.3% (95% confidence interval, 12.9% to 33.1%). The median duration of PRs was 141 days (range, 62 to 299). Of the hematologic toxicities, 14 (23%) and 24 (39%) patients experienced grade 3 or 4 leukopenia and neutropenia, respectively. The toxicities were feasible. Treatment-related death occurred in one patient who suffered hypovolemic shock induced by hematemesis. The median survival time was 10.0 months and the 1-year survival rate was 36.1%. CONCLUSION: Combination chemotherapy with concurrent administration of CPT-11 and VP-16 with rhG-CSF support was only modestly effective against metastatic NSCLC, with feasible toxicities of moderate diarrhea and pulmonary toxicity. The results were equivalent to those expected with either cisplatin-based chemotherapy or with CPT-11 alone.

A radioimmunoassay for circulating human proinsulin.

A radioimmunoassay for human proinsulin (hPl) has been developed using biosynthetic hPl prepared by recombinant DNA technology as immunogen, standard, and tracer. The antiserum was raised in a guinea pig and then adsorbed against insulin and C-peptide conjugated to Sepharose to improve its specificity. After adsorption of the antiserum, the cross-reactivities to insulin and C-peptide were each less than 0.2%. Competition studies using in vitro enzymatically split forms of proinsulin demonstrated that the major antigenic determinant recognized was the junctional region between the B-chain of insulin and the C-peptide. The range of the assay extended from 10 to 150 fmol/tube, with a 50% displacement of 45-55 fmol/tube. This sensitivity proved suitable for measurements of serum hPl concentrations during infusion of biosynthetic hPl into normal subjects and type I diabetic subjects. Eighty-five of 89 serum samples from the normal subjects and each of 20 samples from diabetic subjects diluted in parallel with the hPl standard. Since the direct assay sensitivity was not sufficient for measurement of endogenous hPl levels, a simple procedure for quantitative extraction of proinsulin-like material (PLM) from up to 40 ml of plasma on insulin antibody-Sepharose columns was developed. Logit-log slopes were calculated for dilutions of extracts of samples collected in the fasting state and 60 min after 75 g or oral glucose from eight healthy subjects. The slopes of 15 of the 16 samples did not differ significantly from the slope of the hPl standard.(ABSTRACT TRUNCATED AT 250 WORDS)

Limited sampling model for the area under the concentration versus time curve of irinotecan and its application to a multicentric phase II trial.

We previously established a limited sampling model (LSM) for the area under the concentration versus time curve (AUC) of irinotecan (CPT-11). Using this LSM, we performed a pharmacokinetic-pharmacodynamic analysis of CPT-11 in a multicentric Phase II study for non-small cell lung cancer. Ten institutes participated in this study, 36 patients were registered, and 30 patients were evaluable for the pharmacokinetic-pharmacodynamic analysis. CPT-11 and etoposide were administered daily for three consecutive days, both at a dose of 60 mg/m2. Blood samples were obtained 4 and 8 h after infusion on days 1 and 3. When using the LSM, there is a significant possible source of error in the timing of these selected points. In this study, however, the sample timing error was small. Mean timing errors were 1.0-4.0 min at each point. The estimated CPT-11 AUCs were: Day 1 Day 2 Day 1 + 3 Mean +/- SD (mg.h/liter) 3.76+/-0.68 4.10+/-0.86 7.86+/-1.43 Range 2.01-5.03 2. 29-5.72 4.30-10.68 Max/min 2.50 2.45 2.48 High interpatient variability was observed in the AUC. The CPT-11 AUC correlated positively with the grade of emesis (P = 0.003) and the percent decreases in WBC count (P = 0.001) and absolute neutrophil count (P =0.0006), but it did not correlate with the grade of diarrhea or response. We concluded that the LSM was useful in estimating individual pharmacokinetic parameters in multicentric trials.

Synthetic selective inhibitors of coagulation factor Xa strongly inhibit thrombin generation without affecting initial thrombin forming time necessary for platelet activation in hemostasis.

DX-9065a and JTV-803, synthetic selective inhibitors of activated factor X (FXa), have recently been demonstrated as strongly effective antithrombotic agents in animal thrombosis models, yet with a low risk of bleeding. The aim of the present study was to elucidate these characteristics. Using a chromogenic assay with purified coagulation factors, 73.9% of thrombin generation was suppressed by the addition of DX-9065a (0.20 microm) and 75.7% by JTV-803 (0.18 microm). Inhibition by argatroban (0.19 microm) was less (36.0%) and initial thrombin forming time (T50), the time required to generate 50% thrombin activity in vitro, which is considered important for platelet aggregation in hemostasis, was significantly prolonged by argatroban. In contrast, DX-9065a and JTV-803 had no apparent influence on T50, suggesting that initial thrombin was formed immediately, as in the control. We also investigated platelet aggregation in defibrinated plasma induced by tissue factor, to clarify whether initial thrombin contributes to hemostasis. Aggregation was not affected by the addition of either FXa inhibitor, whereas it was significantly reduced by argatroban. Our results suggest that initial thrombin, which is formed despite the presence of a FXa inhibitor, can activate platelets. We concluded that DX-9065a and JTV-803 are able to inhibit thrombin generation significantly without affecting the formation of initial thrombin for platelet activation, which may contribute to hemostasis through the preservation of normal bleeding time.

Conformation and immunogenicity of engineered repeating segment of the circumsporozoite surface protein of Plasmodium falciparum.

Peptide vaccines based on units of the immunodominant tetrapeptide repeats, Asn-Ala-Asn-Pro and Asn-Val-Asp-Pro, of the circumsporozoite surface protein of the parasite Plasmodium falciparum are presently being developed as potential malaria vaccines. The N-terminal fusion of a hydrophobic protein to units of the tetrapeptide repeat affected the immunogenicity and conformational stability of the peptide, and also induced a secondary structure in the peptide. Peptide antigenicity, as well as conformational stability, was significantly increased.

Gametocytogenesis induction by ammonium compounds in cultured Plasmodium falciparum.

Asexual parasites of a strain that seldom or never produce gametocytes in in vitro culture began gametocytogenesis after 24 h treatment with RPMI 1640 medium containing concanavalin A (final concentration, 10 micrograms ml-1) and ammonium carbonate (final concentration, 15 mM ml-1) or ammonium bicarbonate (final concentration, 15 mM ml-1). Gametocytogenesis was consistently observed from the 3rd day after the treatment. Concanavalin A enhanced gametocytogenesis induction by ammonium carbonate or ammonium bicarbonate, although concanavalin A does not itself have gametocytogenesis induction activity. Whereas no gametocytogenesis was observed after addition of concanavalin A and ammonium acetate (final concentration, 5-25 mM ml-1) or ammonium chloride (final concentration, 5-15 mM-1). Addition of ammonium compounds resulted in decrease of parasitemia, regardless of gametocytogenesis.

Isolation of antigen from the circulating immune complex in mice infected with Plasmodium berghei.

Circulating immune complex (CIC) is known to play a role in pathological glomerular alterations in malaria. However, the nature of the antigens comprising the CIC is still not fully understood. We report here the isolation of the antigen in CIC and its localisation in mice infected with Plasmodium berghei NK65. The antigen was successfully isolated from CIC extracted from the blood of mice infected with P. berghei, by using C1q-coated microplates. The molecular mass of the antigen separated from CIC bound to C1q was found to be 78 kDa. Furthermore, localisation of the antigen was examined by the fluorescent antibody technique and immunoelectron microscopy. The antigen was detected in the parasitised erythrocyte and the mesangial matrix by both methods. These results suggest that the 78 kDa protein might be associated with the glomerular alterations in malaria infection.

Concurrent chemotherapy and thoracic radiation therapy for limited-stage small cell lung cancer.

We conducted a phase II study of therapy for limited-stage small cell lung cancer (LD-SCLC). The chemotherapy regimen consisted of a three-week cycle of cisplatin (80 mg/m(2), given intravenously on day 1) and etoposide (100 mg/m(2), given intravenously on days 1, 3 and 5), given three to four times. Fifty Cy thoracic irradiation was administered in standard fractions simultaneously without a treatment break. A total of 19 patients with SCLC were entered into the study, and 18 were eligible. This concurrent treatment produced 39% complete-response and 89% overall-response rates in the eligible patients. The median response duration was 36 weeks, and the median survival time was 67 weeks. A local relapse within the irradiation field was observed in 28% of the eligible patients. Brain metastasis as the first relapse was seen in 33% of the eligible patients. Myelosuppression represented by grade 3 and 4 leukopenia was experienced in 79% of the entered patients. We conclude that the concurrent modality with cisplatin and etoposide (PE) chemotherapy and early thoracic radiation therapy without split is a feasible and beneficial therapy.

A phase II trial of oral UFT plus cisplatin (CDDP) in patients with non-small cell lung cancer (NSCLC).

Based on the results of our previous pilot study, we conducted a multi-institutional phase II study of combination chemotherapy consisting of oral UFT (Taiho Pharmaceutical Co. Ltd, Tokyo) plus cisplatin (CDDP) in patients with advanced non-small cell lung cancer (NSCLC). UFT capsule containing 100 mg tegafur and 224 mg uracil was orally administered in two divided doses on days 1 through 21 making the total tegafur dose 400 mg/m(2)/day (maximum 600 mg/body). CDDP was administered by drip infusion at a dose of 20 mg/m(2) on a 5-day schedule from day 8 to 12. Treatment was repeated every 4 weeks as long as the criteria for initiation of therapy were still met. Between April 1995 and March 1997, 51 patients were entered into the study. The mean age of all 50 eligible patients was 64 years(range: 40-78). There were 21 patients with clinical stage IIIB disease and 29 patients with IV disease. Thirty-two patients had adenocarcinoma, 14 had epidermoid carcinoma, and four had large cell carcinoma. Of the 47 assessable patients, 18 achieved a partial response with an overall response rate of 38.3% (95% confidence interval: 24.4-52.2%). The median response duration was 113 days. The median survival time of the eligible patients was 12.8 months, and the 1-year survival rate was 54%. Among the 51 patients enrolled, grade 3 or 4 leukopenia developed in one patient (2%), neutropenia in six patients (11. 8%), thrombocytopenia in six patients (11. 8%), and anemia in three patients (5. 9%). Non-hematological grade 3 or 4 toxicities included anorexia in 10 patients (19.6%), nausea in ten (19.6%), vomiting in two (3.9%), and diarrhea in two (3. 9%). Grade 3 abnormal laboratory data included bilirubinemia in four (7. 8%), GPT elevation in one (2.0%), and hematuria in one (2.0%). In conclusion, combination of CDDP plus oral UFT is efficacious, with low toxicity, in the treatment of advanced NSCLC. In particular, the low hematological toxicity may warrant application of this regimen to the treatment of elderly patients and in trials of concurrent chemoradiotherapy in patients with locally advanced NSCLC.

Evaluation of the automatic fluorescent image analyzer, Image Titer, for quantitative analysis of antinuclear antibodies.

By making comparisons with the usual manual method, we evaluated an automatic fluorescent image analyzer (Image Titer, Tripath Imaging, Burlington NC), the software for which was developed to simplify measuring indirect immunofluorescent antinuclear antibodies (FANAs). In this new system, images of the stained sample are displayed, and it measures the FANA titer and staining pattern using only 1 slide per subject and does not required the staining of a series of diluted samples as does the manual method. This system showed good reproducibility and linearity for 4 types of control serum samples (with homogeneous, speckled, discrete speckled, and nucleolar staining patterns). In 132 serum samples, consistency between the methods was 100% for the FANA staining pattern and 93.9% for the FANA titer. The Image Titer system detected each pattern in samples with 2 mixed patterns. This system should partly reduce labor and lead to results with minimum differences among individuals, including newly trained persons.