Digital breast tomosynthesis plus synthesised mammography versus digital screening mammography for the detection of invasive breast cancer (TOSYMA): a multicentre, open-label, randomised, controlled, superiority trial.

BACKGROUND: Two dimensional (2D) full-field digital mammography is the current standard of breast cancer screening. Digital breast tomosynthesis generates pseudo-three dimensional datasets of the breast from which synthesised 2D (s2D) mammograms can be reconstructed. This innovative approach reduces the likelihood of overlapping breast tissues that can conceal features of malignancy. We aimed to compare digital breast tomosynthesis plus s2D mammography with digital screening mammography for the detection of invasive breast cancer. METHODS: TOSYMA was a randomised, open-label, superiority trial done at 17 screening units in two federal states of Germany. Eligible participants were women aged 50-69 years who had been invited to participate in a population-wide, quality-controlled mammography screening programme. Women were randomly assigned (1:1) to digital breast tomosynthesis plus s2D mammography or digital mammography alone using block randomisation (block size of 32), stratified by site. The primary endpoints were the detection rate of invasive breast cancer and invasive interval cancer rate at 24 months, analysed in the modified full analysis set, which included all randomly assigned participants who underwent either type of screening examination. Ten examinations, corresponding to a second study participation, were excluded. Analyses were done according to the intention-to-treat principle. Interval cancer rates will be reported in the follow-up study. Safety was assessed in the as-treated population, which included all participants who were randomly assigned. This trial is registered with ClinicalTrials.gov, NCT03377036, and is closed to accrual. FINDINGS: Between July 5, 2018, and Dec 30, 2020, 99 689 women were randomly assigned to digital breast tomosynthesis plus s2D mammography (n=49 804) or digital mammography (n=49 830). Invasive breast cancers were detected in 354 of 49 715 women with evaluable primary endpoint data in the digital breast tomosynthesis plus s2D group (detection rate 7·1 cases per 1000 women screened) and in 240 of 49 762 women in the digital mammography group (4·8 cases per 1000 women screened; odds ratio 1·48 [95% CI 1·25-1·75]; p<0·0001). Adverse events and device deficiencies were rare (six adverse events in each group; 23 device deficiencies in the digital breast tomosynthesis plus s2D group vs five device deficiencies in the digital mammography group) and no serious adverse events were reported. INTERPRETATION: The results from this study indicate that the detection rate for invasive breast cancer was significantly higher with digital breast tomosynthesis plus s2D mammography than digital mammography alone. Evaluation of interval cancer rates in the follow-up study will further help to investigate incremental long-term benefits of digital breast tomosynthesis screening. FUNDING: Deutsche Forschungsgemeinschaft (German Research Foundation).

Genetic Polymorphisms Affecting Cardiac Biomarker Concentrations in Children with Cancer: an Analysis from the "European Paediatric Oncology Off-patents Medicines Consortium" (EPOC) Trial.

BACKGROUND AND OBJECTIVES: Doxorubicin plays an essential role in the treatment of paediatric cancers. Defining genotypes with a higher risk for developing anthracycline-induced cardiotoxicity could help to reduce cardiotoxicity. METHODS: Data originated from a phase II study assessing the pharmacokinetics of doxorubicin in 100 children. Studied patients (0-17 years) were treated for solid tumours or leukaemia. Two cycles of doxorubicin were studied. Concentrations of natriuretic peptides proANP, BNP and NT-proBNP and cardiac troponins T and I were measured at five time points before, during and after two cycles of doxorubicin treatment. Genotypes of 17 genetic polymorphisms in genes encoding for anthracycline metabolizing enzymes and drug transporters were determined for each patient. We analysed the influence of genotypes on cardiac biomarker concentrations at different time points by a Kruskal-Wallis test. To perform a pairwise comparison significant genetic polymorphisms with more than two genotypes were analysed by a post hoc test. RESULTS: The Kruskal-Wallis tests and the post hoc-tests showed a significant association for seven genetic polymorphisms (ABCB1-rs1128503, ABCB1-rs1045642, ABCC1-rs4148350, CBR3-rs8133052, NQO2-in/del, SLC22A16-rs714368 and SLC22A16-rs6907567) with the concentration of at least one biomarker at one or more time points. We could not identify any polymorphism with a consistent effect on any biomarker over the whole treatment period. CONCLUSIONS: In this study of patients treated with doxorubicin for different tumour entities, seven genetic polymorphisms possibly influencing the pharmacokinetics and pharmacodynamics of doxorubicin could lead occasionally to differences in the concentration of cardiac biomarkers. Since, the role of cardiac biomarkers for monitoring anthracycline-induced cardiotoxicity has not yet been clarified, further trials with a long follow-up time are required to assess the impact of these genetic polymorphisms on chemotherapy-related cardiotoxicity. TRIAL REGISTRATION: EudraCT number: 2009-011454-17.

Digital breast tomosynthesis plus synthesised images versus standard full-field digital mammography in population-based screening (TOSYMA): protocol of a randomised controlled trial.

INTRODUCTION: Development of digital breast tomosynthesis (DBT) provides a technology that generates three-dimensional data sets, thus reducing the pitfalls of overlapping breast tissue. Observational studies suggest that the combination of two-dimensional (2D) digital mammography and DBT increases diagnostic accuracy. However, because of duplicate exposure, this comes at the cost of an augmented radiation dose. This undesired adverse impact can be avoided by using synthesised 2D images reconstructed from the DBT data (s2D).We designed a diagnostic superiority trial on a high level of evidence with the aim of providing a comparison of screening efficacy parameters resulting from DBT+s2D versus the current screening standard 2D full-field digital mammography (FFDM) in a multicentre and multivendor setting on the basis of the quality-controlled, population-based, biennial mammography screening programme in Germany. METHODS AND ANALYSIS: 80 000 women in the eligible age 50-69 years attending the routine mammography screening programme and willing to participate in the TOSYMA trial will be assigned by 1:1 randomisation to either the intervention arm (DBT+s2D) or the control arm (FFDM) during a 12-month recruitment period in screening units of North Rhine-Westphalia and Lower Saxony. State cancer registries will provide the follow-up of interval cancers.Primary endpoints are the detection rate of invasive breast cancers at screening examination and the cumulative incidence of interval cancers in the 2 years after a negative examination. Secondary endpoints are the detection rate of ductal carcinoma in situ and of tumour size T1, the recall rate for assessment, the positive predictive value of recall and the cumulative 12-month incidence of interval cancers. An adaptive statistical design with one interim analysis provides the option to modify the design. ETHICS AND DISSEMINATION: This protocol has been approved by the local medical ethical committee (2016-132-f-S). Results will be submitted to international peer-reviewed journals. TRIAL REGISTRATION: NCT03377036; Pre-results.

Towards a Model-Based Dose Recommendation for Doxorubicin in Children.

Following the publication of our paper regarding a population-based model of doxorubicin pharmacokinetics in children in Clinical Pharmacokinetics last year (Voller et al. 54:1139-1149, 2015), we have received many inquiries on the practical clinical consequences of this model; however, a population-based model is only one of the aspects to be taken into account when developing dosing algorithms. In addition, any new method of dose calculation would need clinical validation and, subsequently, a new clinical trial. However, such a trial, especially with regard to burden to the children involved, requires optimal preparation and the selection of the best hypotheses. The European Paediatric Oncology Off-Patent Medicines Consortium (EPOC), represented by the authors, would therefore like to initiate an interdisciplinary discussion on the clinical and pharmacological goals for dose calculation. This current opinion summarizes the existing knowledge on the pharmacokinetics and pharmacodynamics of doxorubicin. Our aim was to define the clinical needs as precisely as possible, with the intention of stimulating discussion between the clinical pediatric oncologist and the pediatric pharmacologist. By doing so, we hope to define surrogates for best practice of a common doxorubicin dose in children. The intent is for a trial to validate a rational dose calculation rule, leading to a regulatory process and subsequent labeling.

Pharmacokinetic and pharmacodynamic study of doxorubicin in children with cancer: results of a "European Pediatric Oncology Off-patents Medicines Consortium" trial.

PURPOSE: Doxorubicin is a key component in many pediatric oncology treatment regimens; still pharmacology data on which current dosing regimens are based are very limited. METHODS: We conducted a multinational pharmacokinetic study investigating age dependency of doxorubicin metabolism and elimination in children with cancer. One hundred and one patients treated with doxorubicin according to a cancer-specific national or European therapeutic trial were recruited. Doses of doxorubicin ranged from 10.4 to 57.7 mg/m2. Blood samples for measurement of doxorubicin and its metabolite doxorubicinol were collected after two administrations, with five samples collected in children <3 years and eight in children ≥3 years. A population pharmacokinetic approach was used for analysis, including pharmacogenetic covariates. Natriuretic peptides and cardiac troponins were measured to evaluate their role as early indicators of cardiotoxicity. RESULTS: Age dependence of doxorubicin clearance was demonstrated, with children less than 3 years having a statistically significant lower clearance (21.1 ± 5.8 l/h/m2) than older children (26.6 ± 6.7 l/h/m2) (p = 0.0004) after correcting for body surface area. No effect of the investigated genetic polymorphisms on the pharmacokinetics could be observed. Although natriuretic peptides were transiently elevated after each doxorubicin administration and troponin levels increased with increasing doxorubicin exposure, only limited correlation could be observed between their blood levels and doxorubicin pharmacokinetics. CONCLUSION: In the European framework of funding and regulatory support, an add-on study to existing therapeutic trials was developed. The pediatric need concerning missing PK data could be addressed with limited burden for the patients. Empirically used dose adaptations for infants were generally found to be justified based on our PK analyses.

Age-Dependent Pharmacokinetics of Doxorubicin in Children with Cancer.

BACKGROUND AND OBJECTIVE: Knowledge on the pharmacokinetics of doxorubicin, especially in children, is very limited with conflicting evidence concerning a possible age dependency in the pharmacokinetics. The aim of the current investigation was to assess, by using population pharmacokinetics, whether an age dependency in the clearance (CL) of doxorubicin exists. METHODS: Pharmacokinetic data of doxorubicin and its main metabolite doxorubicinol from 94 children (aged 0-18 years) from the EPOC-MS-001-Doxo trial were available. A population pharmacokinetic model was developed in NONMEM(®) 7.2.0. RESULTS: A linear three-compartment model for doxorubicin, with one additional compartment for doxorubicinol, gave the best fit to the data. All model parameters were linearly scaled on body surface area. Including a power function of age as a covariate for CL led to a further improvement of the model. Variation in genes encoding for enzymes involved in the metabolism or active transport of doxorubicin had no influence on the pharmacokinetics. Estimates of CL were lower (26.6 L/h/m(2) in children aged >3 years and 21.1 L/h/m(2) in children aged ≤3 years, p = 0.0004) in children aged <3 years, compared with older children. CONCLUSIONS: This is the first model to describe the pharmacokinetics of doxorubicin in children, with a specific focus on infants and children aged <3 years. The lower CL in younger children should be considered together with the pharmacodynamics, especially the cardiotoxicity, when selecting the dose for future protocols.

Sources of preanalytical error in pharmacokinetic analyses - focus on intravenous drug administration and collection of blood samples.

INTRODUCTION: Pharmacokinetic (PK) studies for long-established drugs are generally performed outside the well-standardized settings of pharmaceutical industry trials. Instead, such studies are usually performed within daily clinical practice of hospitals. AREAS COVERED: This article describes aspects of intravenous (i.v.) drug administration and blood sampling that contribute to potential sources of preanalytical errors for PK investigations. Parameters that bias determination of start and end time of i.v. infusions, as well as consistent rate of drug delivery, are discussed. Causes for drug loss in the infusion device, including adsorption and insufficient flushing, are outlined. The advantages and disadvantages of different blood sampling techniques are reviewed, with an emphasis on pediatric studies. EXPERT OPINION: For PK studies that are integrated into the general hospital routine, a variety of potential sources of error exist. Potential pitfalls depend on the specific drug and trial characteristics and they must be anticipated and discussed in advance. Working procedures need to be developed that address the anticipated problems and in detail describe procedures that need compliance between bed and bench.

Population pharmacokinetics of doxorubicin: establishment of a NONMEM model for adults and children older than 3 years.

PURPOSE: The aim of the current investigation was to develop a population pharmacokinetic model for doxorubicin and doxorubicinol that could provide improved estimated values for the pharmacokinetic parameters clearance of doxorubicin, volume of distribution of the central compartment, clearance of doxorubicinol and volume of distribution of the metabolite compartment for adults and children older than 3 years. A further aim was to investigate the potential influence of the covariates body surface area, body weight, body height, age, body mass index, sex and lean body mass on the pharmacokinetic parameters. METHODS: Three different datasets, two containing data from adults and one containing data from adults and children, were merged and the combined dataset was analysed retrospectively. In total, the combined dataset contained 934 doxorubicin and 935 doxorubicinol plasma concentrations from 82 patients [64 adults and 18 children (<18 years)]. With this combined dataset, a population pharmacokinetic model was developed, using NONMEM(®) 7.2 and a predefined model-building strategy. Different structural models, error models and estimation methods were tested, and the inter-individual and the inter-occasion variability (variability between separate (two or three) doxorubicin infusions) were tested. Using a subset of 52 patients, the influence of different covariates on the pharmacokinetic parameters was investigated. The pharmacokinetic parameter estimates obtained from doxorubicin concentrations with the best model were fixed, and an additional compartment for doxorubicinol was added to the model. With the final model for both substances, a potential age dependency and body mass index dependency of the clearance of doxorubicin and doxorubicinol as well as of the volumes of distribution of the central and the metabolite compartment were evaluated. RESULTS: A four-compartment model best described the doxorubicin and doxorubicinol data of the combined dataset. This model included a proportional residual error model and an inter-individual variability on the clearance of doxorubicin, on the inter-compartmental clearances of the peripheral compartments, on the clearance of doxorubicinol and on the volumes of distribution of the central, one peripheral and the metabolite compartment. Furthermore, the body surface area as covariate on all pharmacokinetic parameters and an inter-occasion variability for the clearance of doxorubicin and the volume of distribution of the central compartment were incorporated in the model. For a patient with the body surface area of 1.8 m², the clearance of doxorubicin was 53.3 L/h (inter-individual variability 31%, inter-occasion variability 13%) and the volume of distribution of the central compartment was 17.7 L (inter-individual variability 19%, inter-occasion variability 21%), respectively. The residual variability of the model was 22% for doxorubicin and 26% for doxorubicinol. The clearance of doxorubicinol was estimated at 44 L/h (inter-individual variability 50%) and the volume of distribution of the metabolite compartment at 1,150 L (inter-individual variability 57%). The evaluation of a possible age dependency and body mass index dependency showed a trend to a smaller volume of distribution of the central compartment (normalised to the body surface area) and a higher volume of distribution of the metabolite compartment (normalised to the body weight) in younger patients. CONCLUSIONS: A four-compartment NONMEM(®) model for doxorubicin and doxorubicinol adequately described the plasma concentrations in adults and children (>3 years). No pronounced effects of age on the clearance of doxorubicin or doxorubicinol were found, and the analysis did not support the modification of the dosing strategies presently used in children and adults.

Minimization of the preanalytical error in pharmacokinetic analyses and therapeutic drug monitoring: focus on IV drug administration.

BACKGROUND: The conduct of multicenter pharmacokinetic (PK) analyses for long-established drugs entails specific problems, because samples have to be obtained within daily clinical practice. Practices for intravenous (IV) drug administration vary between hospitals, including the use of different infusion devices, the use of infusion line systems with different line volumes, and different priming and rinsing procedures. METHODS: Variables of IV drug administration that could influence concentration data obtained in PK analyses were evaluated. Kinetics of drug delivery during initiation and cessation of IV infusions were simulated in vitro for a drop-counter and a syringe-driven infusion system at different flow rates. Furthermore, the percentages of the target drug dosage remaining in the infusion line after different rinsing periods were investigated in vitro and in clinical practice. RESULTS: Varying times required for the drug to migrate from the bag/syringe to the cannula and to reach a steady-state drug administration rate were observed. Time to steady state ranged from almost immediate to 48 minutes depending on the infusion system and flow rate. The longest times were seen for the drop-counter system at low flow rates and were associated with large drug concentration gradients in the infusion line, which makes it difficult to accurately determine start and end of the infusion. For most systems, when rinsing at the end of infusion was performed with once the volume of the infusion line, <5% of the total drug dosage was discarded. Larger variability was seen for slow infusion rates and small infusion volumes. CONCLUSIONS: The choice of the infusion apparatus, standardized infusion systems, and standardized operating procedures for drug administration are important when performing postmarketing PK analyses in multicentric studies.

Minimization of the preanalytical error in plasma samples for pharmacokinetic analyses and therapeutic drug monitoring--using doxorubicin as an example.

BACKGROUND: There are many sources of variability in plasma samples drawn for pharmacokinetic analyses or therapeutic drug monitoring. In this article, methods are proposed on how to prevent sample dilution (Part I) and contamination effects (Part II) in plasma samples, using doxorubicin as an example. METHODS: Experiments were performed in the laboratory setting to identify factors that could influence plasma samples in clinical practice. In part I, it was hypothesized that saline solution left in a catheter could lead to a dilution of samples drawn through this catheter. The impact of 2 different sampling techniques, the "discard method" and the "push-pull method", was examined. In part II, an infusion system was filled with a 1 mg/mL solution of doxorubicin. After rinsing the system with increasing volumes of saline solution, the drug concentration of the fluid left in the system was analyzed. Furthermore, plasma samples were drawn through the drug administration catheter, and the contamination of these samples with doxorubicin left in the catheter was measured. RESULTS: In part I, a discard volume of plasma equal to 4 dead volumes of the sampling line was necessary to avoid dilution of a sample taken from a port or double-lumen catheter filled with saline solution ("discard method"). Pulling up and down the same volume through the catheter 5 times ("push-pull method") was proved to be an alternative with no need to discard blood. In part II, after rinsing the infusion system with a volume of saline solution corresponding to 4 dead volumes of the system and after discarding a volume of plasma corresponding to 4 sampling line volumes, the doxorubicin contamination in the samples was negligibly small. CONCLUSIONS: Under the described conditions, the push-pull method delivered the same results as the discard method to prevent sample dilution. To avoid contamination in plasma samples, development of standardized sampling procedures seems to be essential and feasible.

Dictyostelium Dock180-related RacGEFs regulate the actin cytoskeleton during cell motility.

Cell motility of amoeboid cells is mediated by localized F-actin polymerization that drives the extension of membrane protrusions to promote forward movements. We show that deletion of either of two members of the Dictyostelium Dock180 family of RacGEFs, DockA and DockD, causes decreased speed of chemotaxing cells. The phenotype is enhanced in the double mutant and expression of DockA or DockD complements the reduced speed of randomly moving DockD null cells' phenotype, suggesting that DockA and DockD are likely to act redundantly and to have similar functions in regulating cell movement. In this regard, we find that overexpressing DockD causes increased cell speed by enhancing F-actin polymerization at the sites of pseudopod extension. DockD localizes to the cell cortex upon chemoattractant stimulation and at the leading edge of migrating cells and this localization is dependent on PI3K activity, suggesting that DockD might be part of the pathway that links PtdIns(3,4,5)P(3) production to F-actin polymerization. Using a proteomic approach, we found that DdELMO1 is associated with DockD and that Rac1A and RacC are possible in vivo DockD substrates. In conclusion, our work provides a further understanding of how cell motility is controlled and provides evidence that the molecular mechanism underlying Dock180-related protein function is evolutionarily conserved.

Tyrosine phosphatase inhibition induces loss of blood-brain barrier integrity by matrix metalloproteinase-dependent and -independent pathways.

Tight junctions between endothelial cells of brain capillaries form the structural basis of the blood-brain barrier (BBB), which controls the exchange of molecules between blood and CNS. Regulation of cellular barrier permeability is a vital and complex process involving intracellular signalling and rearrangement of tight junction proteins. We have analysed the impact of tyrosine phosphatase inhibition on tight junction proteins and endothelial barrier integrity in a primary cell culture model based on porcine brain capillary endothelial cells (PBCEC) that closely mimics the BBB in vitro. The tyrosine phosphatase inhibitor phenylarsine oxide (PAO) induced increased matrix metalloproteinase (MMP) activity, which was paralleled by severe disruption of cell-cell contacts and proteolysis of the tight junction protein occludin. ZO-1 and claudin-5 were not affected. Under these conditions, the transendothelial electrical resistance (TEER) was markedly reduced. PAO-induced occludin proteolysis could be prevented by different MMP inhibitors. Pervanadate (PV) reduced the TEER similar to PAO, but did not increase MMP activity. Cell-cell contacts of PV-treated cells appeared unaffected, and occludin proteolysis did not occur. Our results suggest that tyrosine phosphatase inhibition can influence barrier properties independent of, but also correlated to MMPs. Evidence is given for a role of MMPs in endothelial tight junction regulation at the BBB in particular and probably at tight junctions (TJs) in general.