[Repeated superovulation induction after failure in previous IVF-ET cycles with the ultra-long protocol: Analysis of outcomes of clinical pregnancy]

OBJECTIVE

To analyze the clinical outcomes of repeated superovulation induction in patients with adenomyosis or moderate to severe pelvic endometriosis after failure in previous IVF-ET cycles with the ultra-long protocol.

METHODS

We retrospectively analyzed the clinical data about 37 patients with adenomyosis or moderate to severe pelvic endometriosis in our center from 2009 to 2013, who underwent repeated IVF-ET after failure in the previous cycles with the ultra-long protocol, namely by injection of 2－6 ampoules of 3.75 mg gonadotropin-releasing hormone agonist (GnRH-a). All the patients met the following requirements: hCG-negative at 14 days after transfer, within 3－7 days after menstruation, and properly down-regulated serum follicle stimulating hormone (FSH) (<10 mIU/ml), luteinizing hormone (LH) (<10 mIU/ml), estradiol (E2) (<30 pg/ml), follicle diameter (<10 mm) and endometrial thickness, and received GnRH (Gonal-F, Serono) for ovulation induction. We compared the clinical and laboratory data and pregnancy outcomes between the first and repeated cycles before and after ovulation induction.

RESULTS

The repeated cycles, as compared with previous ones, showed significant increases in the antral follicle count (AFC) on the first day of stimulation (7.55 ± 1.86 vs 6.45 ± 2.5, P<0.05), number of follicles =≥14 mm in diameter on the hCG trigger day (7.81 ± 3.6 vs 5.56 ± 3.68, P<0.05), level of E2 (［2 362.15 ± 1 210.49］ vs ［1 749.22 ± 1 139.44］ pg/ml, P<0.05), and numbers of oocytes retrieved (7.51 ± 3.23 vs 4.78 ± 3.41, P<0.05) and embryos transferred (2.00 ± 0.33 vs 1.50 ± 0.67, P<0.05), exhibited a remarkably reduction in the dose of GnRH (［1 791.65 ± 1 889.41］ vs ［3 439.56 ± 1 836.53］ IU, P<0.05), and achieved a clinical pregnancy rate of 62.16%.

CONCLUSIONS

With proper reduction of the FSH, LH and E2 levels and follicle diameter, repeated superovulation induction for IVF-ET can improve the ovarian response and pregnancy outcomes of the patients with adenomyosis or moderate to severe pelvic endometriosis after failure in the previous IVF-ET cycles with the ultra-long protocol.

The prognostic value of the serum neuron specific enolase and lactate dehydrogenase in small cell lung cancer patients receiving first-line platinum-based chemotherapy

The aim of this study was to investigate the associations of serum levels of neuron-specific enolase (NSE), pro-gastrin releasing peptide (ProGRP), and lactate dehydrogenase (LDH) with clinical response and survival in small cell lung cancer (SCLC) patients receiving first-line platinum-based chemotherapy.One hundred thirty-six patients with SCLC were recruited in this study. All the patients received first-line platinum-based chemotherapy. Clinical efficacy was assessed according to Response Evaluation Criteria in Solid Tumors v1.1 criteria. Serum samples were collected from SCLC patients before chemotherapy. NSE, ProGRP, and LDH levels were measured by commercial electrochemiluminescence immunoassay, enzyme-linked immune sorbent assay, and kinetic spectrophotometric method, respectively.Overall response rate was 71.3% with 97 patients who achieved complete response (CR) +  partial response (PR). NSE and LDH level declined in patients who achieved CR + PR compared with patients in stable disease (SD) and progress disease (PD). Multivariate logistic regression analysis revealed that NSE > 50.324 ng/mL, stage ED, and distant metastases were independent risk factors for patients achieving CR + PR, and chemotherapy > 4 cycles was an independent protective factor in predicting CR + PR. Receiver operating characteristic (ROC) curves presented that expression of NSE, ProGRP, and LDH are of good predicting value for patients achieving CR + PR. Patients with a higher level of NSE and LDH presented worse progression-free survival and overall survival. In addition, multivariate Cox regression analysis showed that NSE level > 50.324 ng/mL and distant metastasis were independently correlated with worse OS.Serum NSE and LDH could be promising biomarkers for predicting therapy response and survival of SCLC patients receiving first-line platinum-based chemotherapy.

Qualification of a select one-stage activated partial thromboplastin time-based clotting assay and two chromogenic assays for the post-administration monitoring of nonacog beta pegol

Essentials Nonacog beta pegol (N9-GP) is an extended half-life, recombinant human factor IX (FIX). One-stage clotting (OSC) and chromogenic FIX activity assays were assessed for N9-GP recovery. OSC STA® -Cephascreen® , ROX FIX and BIOPHEN FIX chromogenic assays were qualified for N9-GP. Other extended half-life factor products should be assessed in a similar way prior to approval.

SUMMARY

Background Nonacog beta pegol (N9-GP) is an extended half-life, glycoPEGylated recombinant human factor IX that is under development for the prophylaxis and treatment of bleeding episodes in hemophilia B patients. Considerable reagent-dependent variability has been observed when one-stage clotting assays are used to measure the recovery of recombinant FIX products, including N9-GP. Objective To qualify select one-stage clotting and chromogenic FIX activity assays for measuring N9-GP recovery. Methods The accuracy and precision of the one-stage clotting assay (with the STA-Cephascreen activated partial thromboplastin [APTT] reagent) and the ROX Factor IX and BIOPHEN Factor IX chromogenic assays for measuring N9-GP recovery were assessed in N9-GP-spiked hemophilia B plasma samples in a systematic manner at three independent sites, with manufacturer-recommended protocols and/or site-specific assay setups, including different instruments. Results For each of the three FIX activity assays qualified on five different reagent-instrument systems, acceptable intra-assay and interassay accuracy and precision, dilution integrity, reagent robustness and freeze-thaw and short-term sample stabilities were demonstrated. The STA-Cephascreen assay showed a limited reportable range at one of the three qualification sites, and the BIOPHEN Factor IX assay showed suspect low-end sensitivity at one of the three qualification sites. An individual laboratory would account for these limitations by adjusting the assay's reportable range; thus, these findings are not considered to impact the respective assay qualifications. Conclusion The one-stage clotting assay with the STA-Cephascreen APTT reagent, the ROX Factor IX chromogenic assay and the BIOPHEN Factor IX chromogenic assay are considered to be qualified for the measurement of N9-GP in 3.2% (0.109 m) citrated human plasma.

Recombinant human C1 esterase inhibitor for prophylaxis of hereditary angio-oedema: a phase 2, multicentre, randomised, double-blind, placebo-controlled crossover trial

BACKGROUND

Hereditary angio-oedema is a recurrent, oedematous disorder caused by deficiency of functional C1 inhibitor. Infusions of plasma-derived C1 esterase inhibitor deter attacks of hereditary angio-oedema, but the prophylactic effect of recombinant human C1 esterase inhibitor has not been rigorously studied. We aimed to assess the efficacy of recombinant human C1 esterase inhibitor for prophylaxis of hereditary angio-oedema.

METHODS

We conducted this phase 2, multicentre, randomised, double-blind, placebo-controlled crossover trial at ten centres in Canada, the Czech Republic, Israel, Italy, Macedonia, Romania, Serbia, and the USA. We enrolled patients aged 13 years or older with functional C1-inhibitor concentrations of less than 50% of normal and a history of four or more attacks of hereditary angio-oedema per month for at least 3 months before study initiation. Patients were randomly assigned centrally (1:1:1:1:1:1), via an interactive response technology system with fixed allocation, to receive one of six treatment sequences. During each sequence, patients received intravenous recombinant human C1 esterase inhibitor (50 IU/kg; maximum 4200 IU) twice weekly, recombinant human C1 esterase inhibitor once weekly and placebo once weekly, and placebo twice weekly, each for 4 weeks with a 1 week washout period between crossover. All patients, investigators, and study personnel who participated in patient care were masked to group allocation during the study. The primary efficacy endpoint was the number of attacks of hereditary angio-oedema observed in each 4 week treatment period. Attack symptoms were recorded daily. The primary efficacy analysis was done in the intention-to-treat population. Safety was assessed in all patients who received at least one injection of study medication. This study is registered with ClinicalTrials.gov, number NCT02247739.

FINDINGS

Between Dec 29, 2014, and May 3, 2016, we enrolled 35 patients, of whom 32 (91%) underwent randomisation (intention-to-treat population) and 26 (81%) completed the study. The mean number of attacks of hereditary angio-oedema over 4 weeks was significantly reduced with recombinant human C1 esterase inhibitor twice weekly (2·7 attacks [SD 2·4]) and once weekly (4·4 attacks [3·2]) versus placebo (7·2 attacks [3·6]), with mean differences of -4·4 attacks (p<0·0001) and -2·8 attacks (p=0·0004), respectively. We recorded adverse events in ten (34%) of 29 patients given twice-weekly recombinant human C1 esterase inhibitor, 13 (45%) of 29 patients given the once-weekly regimen, and eight (29%) of 28 patients given placebo. Headache (twice-weekly treatment) and nasopharyngitis (once-weekly treatment) were the most common adverse events. Two (7%) adverse events (fatigue and headache) were deemed possibly related to treatment with recombinant human C1 esterase inhibitor, but both resolved without additional treatment. No thrombotic or thromboembolic events, systemic allergic reactions (including anaphylaxis), or neutralising antibodies were reported.

INTERPRETATION

Prophylaxis with recombinant human C1 esterase inhibitor provided clinically relevant reductions in frequency of hereditary angio-oedema attacks and was well tolerated. In view of the pharmacokinetic profile of recombinant human C1 esterase inhibitor, our results suggest that efficacy of C1-inhibitor replacement therapy might not be a direct function of plasma trough concentrations of C1 inhibitor.

FUNDING

Pharming Technologies.

Characterization of the I4399M variant of apolipoprotein(a): implications for altered prothrombotic properties of lipoprotein(a)

Essentials Elevated lipoproteinp(a) is an independent and causal risk factor for atherothrombotic diseases. rs3798220 (Ile/Met substitution in apo(a) protease-like domain) is associated with disease risk. Recombinant I4399M apo(a) altered clot structure to accelerate coagulation/delay fibrinolysis. Evidence was found for increased solvent exposure and oxidation of Met residue.

SUMMARY

Background Lipoprotein(a) (Lp[a]) is a causal risk factor for a variety of cardiovascular diseases. Apolipoprotein(a) (apo[a]), the distinguishing component of Lp(a), is homologous with plasminogen, suggesting that Lp(a) can interfere with the normal fibrinolytic functions of plasminogen. This has implications for the persistence of fibrin clots in the vasculature and hence for atherothrombotic diseases. A single-nucleotide polymorphism (SNP) (rs3798220) in the gene encoding apo(a) has been reported that results in an Ile→Met substitution in the protease-like domain (I4399M variant). In population studies, the I4399M variant has been correlated with elevated plasma Lp(a) levels and higher coronary heart disease risk, and carriers of the SNP had increased cardiovascular benefit from aspirin therapy. In vitro studies suggested an antifibrinolytic role for Lp(a) containing this variant. Objectives We performed a series of experiments to assess the effect of the Ile→Met substitution on fibrin clot formation and lysis, and on the architecture of the clots. Results We found that the Met variant decreased coagulation time and increased fibrin clot lysis time as compared with wild-type apo(a). Furthermore, we observed that the presence of the Met variant significantly increased fibrin fiber width in plasma clots formed ex vivo, while having no effect on fiber density. Mass spectrometry analysis of a recombinant apo(a) species containing the Met variant revealed sulfoxide modification of the Met residue. Conclusions Our data suggest that the I4399M variant differs structurally from wild-type apo(a), which may underlie key differences related to its effects on fibrin clot architecture and fibrinolysis.

Development, validation, and clinical pharmacokinetic application of ultra-performance liquid chromatography/tandem mass spectrometry method for simultaneously determining a novel recombinant hirudin derivative (Neorudin) and its active metabolite in human serum

Recombinant Neorudin (EPR-hirudin, EH), a novel, low-bleeding anticoagulant fusion protein, has been developed as an inactive prodrug that is converted to an active metabolite, hirudin variant 2-Lys47 (HV2), at the thrombus site and is undergoing Phase I clinical trials in China. The goal of our present research was to establish a novel ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) method for simultaneously quantifying EH and HV2 in human serum. Furthermore, the method was used in clinical pharmacokinetic study after validation. The stock and dilute working solutions were dissolved in methanol/water (1/1, v/v) to avoid their adsorption. The internal standard (IS) used, had a similar structure to that of EH. The serum sample pretreatment involved protein precipitation with methanol. The volume ratio of the precipitating solvent to the serum sample was 3:1 (300μL methanol: 100μL serum sample). The chromatographic separation was performed using a 300Å C18 column using a multi-step gradient with a mobile phase consisting of acetonitrile:water containing 0.1% formic acid. The detection was carried out using an ESI source in the positive multiple reaction monitoring (MRM) mode. The within and between run precision were in the range of 3.5%-10.3% for EH and 3.3%-8.8% for HV2, and the accuracy of both EH and HV2 was between -4.6% and 2.1%. The extraction recoveries and matrix effect at three quality control (QC) levels for EH and HV2 were satisfactory. The stabilities of EH and HV2 during the storage, preparation, and analysis were confirmed, and the carryover also proved to be acceptable. This technique was efficiently used in Phase I clinical pharmacokinetic trials of EH following intravenous administration of 0.2mg/kg to healthy volunteers.

Similar pharmacokinetics and pharmacodynamics of rapid-acting insulin lispro products SAR342434 and US- and EU-approved Humalog in subjects with type 1 diabetes

AIM

To compare the pharmacokinetics (PK) and pharmacodynamics (PD) of 3 rapid-acting insulin lispro products: SAR342434 solution, United States (US)-approved Humalog and European Union (EU)-approved Humalog.

METHODS

In a single-centre, randomized, double-blind, 3-treatment, 3-period, 6-sequence, crossover, euglycaemic clamp study (NCT02273258), adult male subjects with type 1 diabetes were randomized to receive 0.3 U/kg of SAR342434 solution, US-approved and EU-approved Humalog under fasted conditions. PK and PD (glucose infusion rate [GIR]) were assessed up to 12 hours.

RESULTS

Of the 30 subjects randomized, 28 completed all 3 treatment periods. Mean concentration and GIR vs time profiles were similar for all 3 products. Exposure (INS-C_max , INS-AUC_last and INS-AUC) and activity (GIR_max and GIR-AUC_0-12h ) of SAR342434, US-approved and EU-approved Humalog were similar in all comparisons (point estimates of treatment ratios, 0.95-1.03 for PK parameters and 1.00-1.07 for PD parameters), with 90% confidence intervals for the ratios of geometric least squares means within the pre-specified bioequivalence limit (0.80-1.25) and no significant differences in time-related parameters. Within-subject variability of exposure and activity was low across the 3 clamps, indicating high day-to-day reproducibility in clamp performance, irrespective of the individual product. Adverse events were similar for all 3 products. No safety concerns were noted in vital signs or in laboratory and electrocardiogram data.

CONCLUSIONS

The results of this study demonstrate similarity in insulin lispro exposure profiles and PD activity of SAR342434 solution to both US- and EU-approved Humalog, and between both US- and EU-approved Humalog, supporting the use of SAR342434 solution for injection as a follow-on product.

Induction of H7N9-Cross-Reactive Antibody-Dependent Cellular Cytotoxicity Antibodies by Human Seasonal Influenza A Viruses that are Directed Toward the Nucleoprotein

Antibodies that mediate antibody-dependent cellular cytotoxicity (ADCC) against avian influenza virus subtypes, including H7N9 and H5N1, have been detected in human sera. Using NK cell activation and NK cytotoxicity assays, we compared ADCC-mediating antibodies (ADCC-Abs) in sera collected from healthy infants, children and adults against H7N9 virus-infected cells and recombinant hemagglutinin (HA), neuraminidase (NA), and nucleoprotein (NP) proteins. High titers of ADCC-Abs against H7N9 virus-infected cells were detected in sera from adults and children but not infants. ADCC-Abs titers directed against H7N9 HA or NA proteins. Further analysis showed that ADCC-Abs titers were significantly higher toward H7N9 NP, as compared with H7N9 HA or NA proteins, and correlated strongly with ADCC-Abs titers against H7N9 virus-infected cells. Indeed, ADCC-Abs to NPs of seasonal H1N1 and H3N2 viruses correlated strongly with ADCC-Abs to H7N9 NP, suggesting that seasonal influenza infections and vaccinations may induce these cross-reactive antibodies. Targeting ADCC-Abs to internal proteins may be a potential mechanism of universal vaccine design.

Validation of Ultrasensitive Mutant Huntingtin Detection in Human Cerebrospinal Fluid by Single Molecule Counting Immunoassay

BACKGROUND

The measurement of disease-relevant biomarkers has become a major component of clinical trial design, but in the absence of rigorous clinical and analytical validation of detection methodology, interpretation of results may be misleading. In Huntington's disease (HD), measurement of the concentration of mutant huntingtin protein (mHTT) in cerebrospinal fluid (CSF) of patients may serve as both a disease progression biomarker and a pharmacodynamic readout for HTT-lowering therapeutic approaches. We recently published the quantification of mHTT levels in HD patient CSF by a novel ultrasensitive immunoassay-based technology and here analytically validate it for use.

OBJECTIVE

This work aims to analytically and clinically validate our ultrasensitive assay for mHTT measurement in human HD CSF, for application as a pharmacodynamic biomarker of CNS mHTT lowering in clinical trials.

METHODS

The single molecule counting (SMC) assay is an ultrasensitive bead-based immunoassay where upon specific recognition, dye-labeled antibodies are excited by a confocal laser and emit fluorescent light as a readout. The detection of mHTT by this technology was clinically validated following established Food and Drug Administration and European Medicine Agency guidelines.

RESULTS

The SMC assay was demonstrated to be accurate, precise, specific, and reproducible. While no matrix influence was detected, a list of interfering substances was compiled as a guideline for proper collection and storage of patient CSF samples. In addition, a set of recommendations on result interpretation is provided.

CONCLUSIONS

This SMC assay is a robust and ultrasensitive method for the relative quantification of mHTT in human CSF.

A quantitative systems pharmacology model of blood coagulation network describes in vivo biomarker changes in non-bleeding subjects

Essentials Baseline coagulation activity can be detected in non-bleeding state by in vivo biomarker levels. A detailed mathematical model of coagulation was developed to describe the non-bleeding state. Optimized model described in vivo biomarkers with recombinant activated factor VII treatment. Sensitivity analysis predicted prothrombin fragment 1 + 2 and D-dimer are regulated differently.

SUMMARY

Background Prothrombin fragment 1 + 2 (F1 + 2 ), thrombin-antithrombin III complex (TAT) and D-dimer can be detected in plasma from non-bleeding hemostatically normal subjects or hemophilic patients. They are often used as safety or pharmacodynamic biomarkers for hemostatis-modulating therapies in the clinic, and provide insights into in vivo coagulation activity. Objectives To develop a quantitative systems pharmacology (QSP) model of the blood coagulation network to describe in vivo biomarkers, including F1 + 2 , TAT, and D-dimer, under non-bleeding conditions. Methods The QSP model included intrinsic and extrinsic coagulation pathways, platelet activation state-dependent kinetics, and a two-compartment pharmacokinetics model for recombinant activated factor VII (rFVIIa). Literature data on F1 + 2 and D-dimer at baseline and changes with rFVIIa treatment were used for parameter optimization. Multiparametric sensitivity analysis (MPSA) was used to understand key proteins that regulate F1 + 2 , TAT and D-dimer levels. Results The model was able to describe tissue factor (TF)-dependent baseline levels of F1 + 2 , TAT and D-dimer in a non-bleeding state, and their increases in hemostatically normal subjects and hemophilic patients treated with different doses of rFVIIa. The amount of TF required is predicted to be very low in a non-bleeding state. The model also predicts that these biomarker levels will be similar in hemostatically normal subjects and hemophilic patients. MPSA revealed that F1 + 2 and TAT levels are highly correlated, and that D-dimer is more sensitive to the perturbation of coagulation protein concentrations. Conclusions A QSP model for non-bleeding baseline coagulation activity was established with data from clinically relevant in vivo biomarkers at baseline and changes in response to rFVIIa treatment. This model will provide future mechanistic insights into this system.

Factor XIII deficiency enhances thrombin generation due to impaired fibrin polymerization - An effect corrected by Factor XIII replacement

INTRODUCTION

Factor XIII (FXIII) cross-links fibrin, completing blood coagulation. Congenital FXIII deficiency is managed with plasma-derived FXIII (pdFXIII) or recombinant FXIII (rFXIII) concentrates.

AIM

As the mechanisms protecting patients with low FXIII levels (<5IU/dL) from spontaneous bleeds remain unknown we assessed the interplay between thrombin generation (TG), fibrin formation and clot kinetics before and after FXIII administration in three patients with FXIII deficiency.

METHODS

Patients received initially rFXIII (35IU/kg, A-subunit) following with pdFXIII at 1250IU or 2500IU (12-30IU/kg) monthly. TG (CAT), thromboelastometry (ROTEM), prothrombin fragments F1+2, fibrinogen and FXIII activity (FXIII:C) were measured at baseline and one-hour recovery.

RESULTS

FXIII was at the target level of 20±6IU/dL at the 4-week trough. rFXIII corrected FXIII to 98±15 and high-dose pdFXIII to a level of 90±6, whereas low-dose/half dose pdFXIII reached 45±4IU/dL. Although fibrinogen (Clauss Method) was normal, coagulation in FIBTEM was impaired, which FXIII administration tended to correct. CAT implied 1.6- to 1.9-fold enhanced TG, which FXIII administration normalized. Inhibition of fibrin polymerization by Gly-Pro-Arg-Pro peptide mimicked FXIII deficiency in CAT by enhancing TG both in control and FXIII recovery plasma. Antithrombin, α2-macroblobulin-thrombin complex and prothrombin were normal, whereas F1+2 were elevated compatible with in vivo TG.

DISCUSSION

FXIII deficiency impairs fibrinogen function and fibrin formation simultaneously enhancing TG on the poorly polymerizing fibrin strands, when fibrin's antithrombin I -like function is absent. Our study suggests an inverse link between low FXIII levels and enhanced TG modifying structure-function relationship of fibrin to support hemostasis.

Biomarkers of Environmental Enteropathy are Positively Associated with Immune Responses to an Oral Cholera Vaccine in Bangladeshi Children

Environmental enteropathy (EE) is a poorly understood condition that refers to chronic alterations in intestinal permeability, absorption, and inflammation, which mainly affects young children in resource-limited settings. Recently, EE has been linked to suboptimal oral vaccine responses in children, although immunological mechanisms are poorly defined. The objective of this study was to determine host factors associated with immune responses to an oral cholera vaccine (OCV). We measured antibody and memory T cell immune responses to cholera antigens, micronutrient markers in blood, and EE markers in blood and stool from 40 Bangladeshi children aged 3-14 years who received two doses of OCV given 14 days apart. EE markers included stool myeloperoxidase (MPO) and alpha anti-trypsin (AAT), and plasma endotoxin core antibody (EndoCab), intestinal fatty acid binding protein (i-FABP), and soluble CD14 (sCD14). We used multiple linear regression analysis with LASSO regularization to identify host factors, including EE markers, micronutrient (nutritional) status, age, and HAZ score, predictive for each response of interest. We found stool MPO to be positively associated with IgG antibody responses to the B subunit of cholera toxin (P = 0.03) and IgA responses to LPS (P = 0.02); plasma sCD14 to be positively associated with LPS IgG responses (P = 0.07); plasma i-FABP to be positively associated with LPS IgG responses (P = 0.01) and with memory T cell responses specific to cholera toxin (P = 0.01); stool AAT to be negatively associated with IL-10 (regulatory) T cell responses specific to cholera toxin (P = 0.02), and plasma EndoCab to be negatively associated with cholera toxin-specific memory T cell responses (P = 0.02). In summary, in a cohort of children 3-14 years old, we demonstrated that the majority of biomarkers of environmental enteropathy were positively associated with immune responses after vaccination with an OCV.

Protection of the Furin Cleavage Site in Low-Toxicity Immunotoxins Based on Pseudomonas Exotoxin A

Recombinant immunotoxins (RITs) are fusions of an Fv-based targeting moiety and a toxin. Pseudomonas exotoxin A (PE) has been used to make several immunotoxins that have been evaluated in clinical trials. Immunogenicity of the bacterial toxin and off-target toxicity have limited the efficacy of these immunotoxins. To address these issues, we have previously made RITs in which the Fv is connected to domain III (PE24) by a furin cleavage site (FCS), thereby removing unneeded sequences of domain II. However, the PE24 containing RITs do not contain the naturally occurring disulfide bond around the furin cleavage sequence, because it was removed when domain II was deleted. This could potentially allow PE24 containing immunotoxins to be cleaved and inactivated before internalization by cell surface furin or other proteases in the blood stream or tumor microenvironment. Here, we describe five new RITs in which a disulfide bond is engineered to protect the FCS. The most active of these, SS1-Fab-DS3-PE24, shows a longer serum half-life than an RIT without the disulfide bond and has the same anti-tumor activity, despite being less cytotoxic in vitro. These results have significance for the production of de-immunized, low toxicity, PE24-based immunotoxins with a longer serum half-life.

Steady-state volume of distribution of two-compartment models with simultaneous linear and saturated elimination

The model-independent estimation of physiological steady-state volume of distribution ([Formula: see text]), often referred to non-compartmental analysis (NCA), is historically based on the linear compartment model structure with central elimination. However the NCA-based steady-state volume of distribution ([Formula: see text]) cannot be generalized to more complex models. In the current paper, two-compartment models with simultaneous first-order and Michaelis-Menten elimination are considered. In particular, two indistinguishable models [Formula: see text] and [Formula: see text], both having central Michaelis-Menten elimination, while first-order elimination exclusively either from central or peripheral compartment, are studied. The model-based expressions of the steady-state volumes of distribution [Formula: see text] and their relationships to NCA-based [Formula: see text] are derived. The impact of non-linearity and peripheral elimination is explicitly delineated in the formulas. Being concerned with model identifiability and indistinguishability issues, an interval estimate of [Formula: see text] is suggested.

Copper-induced structural conversion templates prion protein oligomerization and neurotoxicity

Prion protein (PrP) misfolding and oligomerization are key pathogenic events in prion disease. Copper exposure has been linked to prion pathogenesis; however, its mechanistic basis is unknown. We resolve, with single-molecule precision, the molecular mechanism of Cu(2+)-induced misfolding of PrP under physiological conditions. We also demonstrate that misfolded PrPs serve as seeds for templated formation of aggregates, which mediate inflammation and degeneration of neuronal tissue. Using a single-molecule fluorescence assay, we demonstrate that Cu(2+) induces PrP monomers to misfold before oligomer assembly; the disordered amino-terminal region mediates this structural change. Single-molecule force spectroscopy measurements show that the misfolded monomers have a 900-fold higher binding affinity compared to the native isoform, which promotes their oligomerization. Real-time quaking-induced conversion demonstrates that misfolded PrPs serve as seeds that template amyloid formation. Finally, organotypic slice cultures show that misfolded PrPs mediate inflammation and degeneration of neuronal tissue. Our study establishes a direct link, at the molecular level, between copper exposure and PrP neurotoxicity.

Serum Biomarkers Associated with Clinical Outcomes Fail to Predict Brain Metastases in Patients with Stage IV Non-Small Cell Lung Cancers

Background

Lung cancers account for the majority of brain metastases which pose major therapeutic challenges. Biomarkers prognosticating for the development of brain metastases in patients with non-small cell lung cancers (NSCLC) may improve personalized care. Six serum proteomic biomarkers were previously investigated at Memorial Sloan Kettering but their associations with brain metastases were unknown.

Methods

Serum NSE, CYFRA 21–1, ProGRP, SCC-Ag, TIMP1, and HE4 by ELISA-based proteomic assays were prospectively collected from consecutive patients with stage IV NSCLC. Pre-treatment serum biomarker levels as well as age, histology, and epidermal growth factor receptor (EGFR) mutation status were evaluated for association with the baseline presence of brain metastases using logistic regression and multivariable analysis. For patients without brain metastases at baseline, the cumulative incidence of subsequent brain metastases were compared according to baseline biomarkers and clinical factors using Gray’s test.

Results

A total of 118 patients were enrolled, 31 (26%; 95% CI 0.19–0.35) had brain metastases at baseline and a further 26 (22%; 95% CI 0.15–0.30) developed brain metastases subsequently. Pre-treatment serum biomarker levels were available in 104 patients. There was no significant association between the six serum biomarkers and the baseline presence or subsequent development of brain metastases. Age younger than 65 years was the only clinical factor significantly associated with brain metastasis at baseline (OR 3.00; 95% CI 1.22–7.34, P = 0.02) by multivariable analysis. A trend toward increased cumulative incidence of subsequent brain metastases was observed in patients with EGFR mutation (p = 0.2), but this was not statistically significant possibly due to small sample size.

Conclusions

Serum NSE, CYFRA 21–1, Pro-GRP, SCC-Ag, TIMP1, and HE4 are not significantly associated with brain metastases. Our methods taking into account follow-up time may be applied to independent datasets to identify a patient cohort with a higher biologic propensity for developing brain metastases. Such information may be useful for the study of agents targeting the development of brain metastases.

GEP-NETs UPDATE: Secreting gastro-enteropancreatic neuroendocrine tumours and biomarkers

Neuroendocrine tumours (NETs) are rare tumours with an annual incidence in the population in a range of 2-5 new cases per 100,000 inhabitants. NETs are widely variable in terms of anatomical location, hormone production, clinical behaviour and syndromes they can cause. This article reviews the many localizations and clinical presentations of NETs with a main focus on clinical biomarkers and their use in medical practice.

Leptin Matures Aspects of Lung Structure and Function in the Ovine Fetus

In human and ovine fetuses, glucocorticoids stimulate leptin secretion, although the extent to which leptin mediates the maturational effects of glucocorticoids on pulmonary development is unclear. This study investigated the effects of leptin administration on indices of lung structure and function before birth. Chronically catheterized singleton sheep fetuses were infused iv for 5 days with either saline or recombinant ovine leptin (0.5 mg/kg · d leptin (LEP), 0.5 LEP or 1.0 mg/kg · d, 1.0 LEP) from 125 days of gestation (term ∼145 d). Over the infusion, leptin administration increased plasma leptin, but not cortisol, concentrations. On the fifth day of infusion, 0.5 LEP reduced alveolar wall thickness and increased the volume at closing pressure of the pressure-volume deflation curve, interalveolar septal elastin content, secondary septal crest density, and the mRNA abundance of the leptin receptor (Ob-R) and surfactant protein (SP) B. Neither treatment influenced static lung compliance, maximal lung volume at 40 cmH2O, lung compartment volumes, alveolar surface area, pulmonary glycogen, protein content of the long form signaling Ob-Rb or phosphorylated signal transducers and activators of transcription-3, or mRNA levels of SP-A, C, or D, elastin, vascular endothelial growth factor-A, the vascular endothelial growth factor receptor 2, angiotensin-converting enzyme, peroxisome proliferator-activated receptor γ, or parathyroid hormone-related peptide. Leptin administration in the ovine fetus during late gestation promotes aspects of lung maturation, including up-regulation of SP-B.

Thrombin generation assay using factor XIa to measure factors VIII and IX and their glycoPEGylated derivatives is robust and sensitive

BACKGROUND

Conventional coagulation factor assays are associated with certain limitations, as they do not always reflect the clinical heterogeneity of bleeding in hemophilic patients or correctly reflect the individual patient response to treatment with bypassing agents or novel factor concentrates. The thrombin generation assay (TGA) is currently being assessed as a possible method for characterizing bleeding phenotypes in individuals with hemophilia.

OBJECTIVES

This study assessed the robustness and sensitivity of the TGA for measuring the activity of recombinant factor VIII (rFVIII), recombinant factor IX (rFIX) and their glycoPEGylated derivatives, N8-GP and N9-GP, in vitro.

METHODS

Factor-deficient plasma was spiked with 0.13-130 IU dL(-1) rFVIII or N8-GP (hemophilia A [HA] plasma), or rFIX or N9-GP (hemophilia B [HB] plasma). A calibrated automated thrombogram triggered with tissue factor (TF) or activated FXI (FXIa) was used to measure thrombin generation over time. Endogenous thrombin potential, peak thrombin, velocity index, lag time and time to peak thrombin were analyzed.

RESULTS

FXIa-triggered assays were not affected by glycoPEGylation and were sufficiently sensitive to differentiate between spiked samples mimicking severe and moderate HB and HA; TF-triggered assays were not sufficiently sensitive for this distinction in HA. Both FXIa-triggered and TF-triggered assays had an acceptable level of variability (≤ 20%), although TF-triggered assays were associated with greater variability.

CONCLUSIONS

FXIa-triggered TGA reactions produced more robust and sensitive results than TF-triggered TGA reactions, and have the potential for use in monitoring patients treated with glycoPEGylated or non-PEGylated coagulation factor concentrates. These promising results merit confirmation with clinical samples to correlate in vitro and in vivo data.

UNBLOCK: an open-label, dose-finding, pharmacokinetic and safety study of bivalirudin in children with deep vein thrombosis

BACKGROUND

Direct thrombin inhibitors offer potential advantages over unfractionated heparin but have been poorly studied in children.

OBJECTIVES

To determine appropriate dosing of bivalirudin in children and adolescents and the relationship between activated partial thromboplastin time (APTT) and plasma bivalirudin concentration.

PATIENTS/METHODS

The UNBLOCK (UtilizatioN of BivaLirudin On Clots in Kids) study was an open-label, single-arm, dose-finding, pharmacokinetic, safety and efficacy study of bivalirudin for the acute treatment of deep vein thrombosis (DVT) in children aged 6 months to 18 years. Drug initiation consisted of a bolus dose (0.125 mg kg(-1) ) followed by continuous infusion (0.125 mg kg h(-1) ). Dose adjustments were based on the APTT, targeting a range of 1.5-2.5 times each patient's baseline APTT. Safety was assessed by specific bleeding endpoints and efficacy by repeat imaging at 48-72 h and 25-35 days.

RESULTS

Eighteen patients completed the study. Following the bolus dose and the initial infusion rate, most patients' APTT values were within the target range. The infusion rate bivalirudin correlated more closely with drug concentration than the APTT. At 48-72 h, nine (50%) patients had complete or partial thrombus resolution, increasing to 16 (89%) at 25-35 days. No major and one minor bleeding event occurred.

CONCLUSIONS

Bivalirudin demonstrated reassuring safety and noteworthy efficacy in terms of early clot resolution in children and adolescents with DVT. Although a widely available and familiar monitoring tool, the APTT correlates poorly with plasma bivalirudin concentration, possibly limiting its utility in managing pediatric patients receiving bivalirudin for DVT.

Pharmacokinetic and pharmacodynamic evaluation of elosulfase alfa, an enzyme replacement therapy in patients with Morquio A syndrome

Background and Objectives

Morquio A syndrome (mucopolysaccharidosis IVA; MPS IVA) is a lysosomal storage disorder caused by deficiency of N-acetylgalactosamine-6-sulfatase, an enzyme required for degradation of the glycosaminoglycan keratan sulfate. Enzyme replacement therapy with elosulfase alfa provides a potential therapy for Morquio A syndrome. We analyzed the pharmacokinetics and pharmacodynamics of elosulfase alfa in Morquio A patients from a phase III clinical trial.

Methods

In a randomized double-blind study, elosulfase alfa at 2.0 mg/kg was administrated weekly or every other week for 24 weeks. Pharmacokinetic parameters of elosulfase alfa were determined at weeks 0 and 22 by non-compartmental analysis. Safety was assessed throughout the study. The relationship of pharmacokinetic parameters to patient demographics, pharmacodynamic assessments, immunogenicity, and efficacy and safety outcomes were assessed graphically by treatment group.

Results

Elosulfase alfa exposure and half-life (t_½) increased for both dose regimens during the study. There appeared to be no consistent trend between drug clearance (CL) and patient’s sex, race, body weight, or age. All patients developed anti-drug antibodies, but no association was noted between total antibody titer and CL. In contrast, positive neutralizing antibody (NAb) status appeared to associate with decreased CL and prolonged t_½ for patients in the cohort dosed weekly. NAb may interfere with receptor-mediated cellular uptake and lead to increased circulation time of elosulfase alfa.

Conclusion

Despite the association between NAb and decreased drug clearance, neither dosing cohort showed associations between drug exposure and change in urinary keratan sulfate, 6-min walk test distances, or the occurrence of adverse events.

Electronic supplementary material

The online version of this article (doi:10.1007/s40262-014-0173-y) contains supplementary material, which is available to authorized users.

Induction dosing of peginterferon alfa-2a (40 KD) and/or high-dose ribavirin in genotype 1 CHC patients with difficult-to-treat characteristics: pharmacokinetic and viral kinetic (PK/VK) assessment from PROGRESS

BACKGROUND/AIMS

PROGRESS randomized chronic hepatitis C genotype 1 patients with a baseline viral load ≥400,000 IU/mL weighing ≥85 kg to regimens of 180 μg/week for 48 weeks or 360 μg/week for 12 weeks followed by 180 μg/week for 36 weeks peginterferon alfa-2a plus ribavirin. This analysis explored pharmacokinetics and early viral kinetics (VK) and evaluates differences between groups.

METHODOLOGY

Blood samples for pharmacokinetic and VK analyses were collected from 51 patients enrolled in the PROGRESS study.

RESULTS

Mean peginterferon alfa-2a trough concentration at week 12 was 11.7±4.3 ng/mL for 180 μg and 23.4±11.3 ng/mL for 360 μg. Early VK profiles suggested a trend towards an enhanced viral decline in the 360 μg groups with a mean decrease in HCV RNA at 48 hours post first dose of 1.04 log10 (IU/mL) compared with 0.76 log10 (IU/mL) in the 180 μg groups. Mean beta slope increased with dose, ranging from 0.38±0.26 log10 IU/week at 180 μg to 0.52±0.32 log10 IU/week at 360 μg.

CONCLUSIONS

Early viral de clines may be enhanced with the 360 μg dose. These data may suggest the utility of high-dose peginterfer on alfa-2a plus direct-acting antivirals (DAA) in select difficult-to-treat populations.

Recombinant erythropoietin in humans has a prolonged effect on circulating erythropoietin isoform distribution

The membrane-assisted isoform immunoassay (MAIIA) quantitates erythropoietin (EPO) isoforms as percentages of migrated isoforms (PMI). We evaluated the effect of recombinant human EPO (rhEPO) on the distribution of EPO isoforms in plasma in a randomized, placebo-controlled, double-blinded, cross-over study. 16 healthy subjects received either low-dose Epoetin beta (5000 IU on days 1, 3, 5, 7, 9, 11 and 13); high-dose Epoetin beta (30.000 IU on days 1, 2 and 3 and placebo on days 5, 7, 9, 11 and 13); or placebo on all days. PMI on days 4, 11 and 25 was determined by interaction of N-acetyl glucosamine with the glycosylation dependent desorption of EPO isoforms. At day 25, plasma-EPO in both rhEPO groups had returned to values not different from the placebo group. PMI with placebo, reflecting the endogenous EPO isoforms, averaged 82.5 (10.3) % (mean (SD)). High-dose Epoetin beta decreased PMI on days 4 and 11 to 31.0 (4.2)% (p<0.00001) and 45.2 (7.3)% (p<0.00001). Low-dose Epoetin beta decreased PMI on days 4 and 11 to 46.0 (12.8)% (p<0.00001) and 46.1 (10.4)% (p<0.00001). In both rhEPO groups, PMI on day 25 was still decreased (high-dose Epoetin beta: 72.9 (19.4)% (p = 0.029); low-dose Epoetin beta: 73.1 (17.8)% (p = 0.039)). In conclusion, Epoetin beta leaves a footprint in the plasma-EPO isoform pattern. MAIIA can detect changes in EPO isoform distribution up til at least three weeks after administration of Epoetin beta even though the total EPO concentration has returned to normal.

Plasma growth hormone-binding protein levels in Atlantic salmon Salmo salar during smoltification and seawater transfer

Specific growth hormone (GH)-binding protein (Ghbp) was purified from Atlantic salmon Salmo salar and rainbow trout Oncorhynchus mykiss plasma with immunoprecipitation and characterized in cross-linking studies using autoradiography and western blots. The size of the Ghbp was estimated to be c. 53 kDa. A radioimmunoassay was established to measure Ghbp in salmonids, using antibodies specific against the extracellular segment of the S. salar growth hormone receptor 1 (grh1; GenBank AY462105). Plasma Ghbp levels were measured in S. salar smolts in fresh water and after transfer to seawater (SW; experiments 1 and 2), and in post-smolts kept at different salinities (0, 12, 22 and 34) for 3 months (experiment 3). A transient increase in plasma Ghbp, which lasted for 1 month or less, was noted in smolts after transfer to SW. Concomitantly, plasma GH and gill Na(+) -K(+) -ATPase activity increased during smoltification (in experiment 2). No difference in plasma Ghbp was evident between post-smolts kept at different salinities, although the fish kept at salinity 34 had higher plasma GH than the group kept at salinity 22 and higher hepatic ghr1 expression than post-smolts kept at salinity 12. This suggests that plasma Ghbp regulation may respond to salinity changes in the short term. The lack of correlation between Ghbp, plasma GH and hepatic ghr1 expression in the long-term post-smolt experiment indicates that Ghbp levels may be regulated independently of other components of the endocrine GH system in salmonids.