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1.
Small ; 20(27): e2311771, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38268308

RESUMO

Insufficient thermal stability of vanadium redox flow battery (VRFB) electrolytes at elevated temperatures (>40 °C) remains a challenge in the development and commercialization of this technology, which otherwise presents a broad range of technological advantages for the long-term storage of intermittent renewable energy. Herein, a new concept of combined additives is presented, which significantly increases thermal stability of the battery, enabling safe operation to the highest temperature (50 °C) tested to date. This is achieved by combining two chemically distinct additives-inorganic ammonium phosphate and polyvinylpyrrolidone (PVP) surfactant, which collectively decelerate both protonation and agglomeration of the oxo-vanadium species in solution and thereby significantly suppress detrimental formation of precipitates. Specifically, the precipitation rate is reduced by nearly 75% under static conditions at 50° C. This improvement is reflected in the robust operation of a complete VRFB device for over 300 h of continuous operation at 50 °C, achieving an impressive 83% voltage efficiency at 100 mA cm‒2 current density, with no precipitation detected in either the electrode/flow-frame or electrolyte tank.

2.
Phys Chem Chem Phys ; 26(28): 19117-19129, 2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-38957118

RESUMO

Ru is a metal of interest in catalysis. Monodisperse Ru3 clusters as catalytic sites are relevant for the development of catalysts because clusters use significantly lower amounts of precious materials for forming active sites due to the small size of the cluster. However, retaining the mono-dispersity of the cluster size after deposition is a challenge because surface energy could drive both agglomeration and encapsulation of the clusters. In the present work Ru3 clusters are deposited by chemical vapor deposition (CVD) of Ru3(CO)12 and cluster source depositions of bare Ru3 onto radio frequency sputter-deposited TiO2 (RF-TiO2) substrates, TiO2(100), and SiO2. When supported on RF-TiO2, bare Ru3 is encapsulated by a layer of titania substrate material during deposition with a cluster source. Ligated Ru3(CO)12 is also encapsulated by a layer of titania when deposited onto sputter-treated RF-TiO2, but only through heat treatment which is required to remove most of the ligands. The titania overlayer thickness was determined to be 1-2 monolayers for Ru3(CO)12 clusters on RF-TiO2, which is thin enough for catalytic or photocatalytic reactions to potentially occur even without clusters being part of the very outermost layer. The implication for catalysis of the encapsulation of Ru3 into the RF-TiO2 is discussed. Temperature-dependent X-ray photoelectron spectroscopy (XPS), angle-resolved XPS, and temperature-dependent low energy ion scattering (TD-LEIS) are used to probe how the cluster-surface interaction changes due to heat treatment and scanning transmission electron microscopy (STEM) was used to image the depth of the surface from side-on.

3.
Langmuir ; 39(36): 12618-12626, 2023 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-37642667

RESUMO

Employing neutral impact collision ion scattering spectroscopy (NICISS), we have directly measured the concentration depth profiles (CDPs) of various monovalent ions at the vapor-formamide interface. NICISS provides CDPs of individual ions by measuring the energy loss of neutral helium atoms backscattered from the solution interface. CDPs at the vapor-formamide interface of Cl-, Br-, I-, Na+, K+, and Cs+ are measured and compared to elucidate the interfacial specific ion trends. We report a reverse Hofmeister series in the presence of inorganic ions (anion and cation) at the vapor-formamide interface relative to the water-vapor interface, and the CDPs are found to be independent of the counterion for most ions studied. Thus, ions at the surface of formamide follow a "Hofmeister paradigm" where the counterion does not impact the ion series. These specific ion trends are complemented with surface tension and X-ray absorption near-edge structure (XANES) measurements on formamide electrolyte solutions.

4.
Langmuir ; 38(38): 11658-11665, 2022 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-36112511

RESUMO

Characterization of bidimensional polymeric films at the air-water interface in the Langmuir trough, despite being a recurrent topic, usually refers to films of already formed polymeric materials, with very scarce reports on direct polymerization at the air-water interface. In the present work, we studied the photo-polymerization of stearyl methacrylate directly at the air-water interface under a nitrogen atmosphere, with the radical initiator solubilized in the aqueous phase. Two-dimensional (2D) polymerization was monitored by measuring the pressure-area isotherm at different irradiation times. The polymerization leads to a film with an isotherm different from that observed for the monomer, where the surface pressure is directly related to the irradiation time. The shape of this isotherm confirms the presence of a compressed liquid phase, where a higher order can be attained as a consequence of stronger packing forces involving polymer chains. The presence of inter-chain interactions allows rearrangements on the surface of the subphase, and even before the collapse a dense 2D ordering (with a solid phase-like behavior) can be observed. We present a new one-step, solvent-free procedure to obtain a photo-polymeric film directly at the air-water interface, which can be transferred to a solid surface by the Langmuir-Blodgett method, allowing film preparation of controlled thickness. Films were characterized by measuring properties such as thickness, roughness, and hydrophobicity and comparing them with films obtained from a conventional polymer. We report the differences between the interfacial behavior of amphiphilic molecules and nanomaterials such as films obtained by photo-polymerization, PSMA, directly on the air-water interface.

5.
Phys Chem Chem Phys ; 24(21): 12682-12718, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35543205

RESUMO

Specific ion effects (SIE), encompassing the Hofmeister Series, have been known for more than 130 years since Hofmeister and Lewith's foundational work. SIEs are ubiquitous and are observed across the medical, biological, chemical and industrial sciences. Nevertheless, no general predictive theory has yet been able to explain ion specificity across these fields; it remains impossible to predict when, how, and to what magnitude, a SIE will be observed. In part, this is due to the complexity of real systems in which ions, counterions, solvents and cosolutes all play varying roles, which give rise to anomalies and reversals in anticipated SIEs. Herein we review the historical explanations for SIE in water and the key ion properties that have been attributed to them. Systems where the Hofmeister series is perturbed or reversed are explored, as is the behaviour of ions at the liquid-vapour interface. We discuss SIEs in mixed electrolytes, nonaqueous solvents, and in highly concentrated electrolyte solutions - exciting frontiers in this field with particular relevance to biological and electrochemical applications. We conclude the perspective by summarising the challenges and opportunities facing this SIE research that highlight potential pathways towards a general predictive theory of SIE.


Assuntos
Eletrólitos , Água , Eletrólitos/química , Íons/química , Solventes , Água/química
6.
Molecules ; 27(19)2022 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-36234895

RESUMO

We investigated the effect of adding p-anisaldehyde (AA) solvent to the ink containing poly[[2,60-4,8-di(5-ethylhexylthienyl)benzo[1,2-b:3,3-b]dithiophene][3-fluoro-2[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]](PTB7-Th) and 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:20,30-d0]-s-indaceno[1,2-b:5,6-b0]-dithiophene(ITIC) on the morphology of the active layer. The present study focuses on determining the effect of the additive on the compositions at the surface of the PTB7-Th: ITIC composite and its morphology, forming one side of the interface of the blend with the MoOX electrode, and the influence of the structural change on the performance of devices. Studies of device performance show that the addition of the additive AA leads to an improvement in device performance. Upon the addition of AA, the concentration of PTB7-Th at the surface of the bulk heterojunction (BHJ) increases, causing an increase in surface roughness of the surface of the BHJ. This finding contributes to an understanding of the interaction between the donor material and high work function electrode/interface material. The implications for the interface are discussed.

7.
Environ Sci Technol ; 55(1): 757-766, 2021 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-33337864

RESUMO

Unwanted growth of fouling organisms on underwater surfaces is an omnipresent challenge for the marine industry, costing billions of dollars every year in the transportation sector alone. Copper, the most widely used biocide in antifouling paints, is at the brink of a total ban in being used in antifouling coatings, as it has become an existential threat to nontargeted species due to anthropogenic copper inputs into protected waters. In the current study, using a porous and cross-linked poly(ethylene imine) structure under marine and fouling environments, available copper from natural seawater was absorbed and electrochemically released back as a potent biocide at 1.3 V vs Ag|AgCl, reducing marine growth by 94% compared to the control electrode (coupon) at 0 V. The coating can also function as an electrochemical copper sensor enabling real-time monitoring of the electrochemical uptake and release of copper ions from natural seawater. This allows tailoring of the electrochemical program to the changing marine environments, i.e., when the vessels move from high-copper-contaminated waters to coastal regions with low concentrations of copper.


Assuntos
Incrustação Biológica , Desinfetantes , Incrustação Biológica/prevenção & controle , Cobre/análise , Pintura , Água do Mar
8.
Phys Chem Chem Phys ; 23(38): 22160-22173, 2021 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-34581338

RESUMO

Surface defects influence the dye adsorption on TiO2 used as a substrate in dye-sensitized solar cells (DSSCs). In this study, we have used different Ar+ sputtering doses to create a controlled density of defects on a TiO2 surface exposed to different pre-heating temperatures in order to analyse the influence of defects on the N719 dye adsorption. TiO2 was pre-treated using two different treatments. The first treatment involved heating to 200 °C with subsequent sputtering at different doses. The second treatment included heating only, but at four different temperatures starting at 200 °C. After the pre-treatments, the TiO2 samples were immersed into an N719 dye solution for 24 hours at room temperature to dye the TiO2 substrates. The amount of Ti3+ surface defects introduced by the different pre-treatments and their influence on dye adsorption onto the TiO2 surface were examined by X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS) and metastable induced electron spectroscopy (MIES). Neutral impact collision ion scattering spectroscopy (NICISS) was used to determine the coverage of the TiO2 surface by adsorbed dye molecules. It was found that Ti3+ surface defects were formed by Ar+ sputtering but not by pre-treatment through heating alone. MIES analysis of the outer-most layer and density of states calculations show that the thiocyanate ligand of the N719 dye becomes directed away from the TiO2 surface. Both XPS and NICISS results indicate that the amount of adsorbed N719 dye decreases with increasing density of Ti3+ surface defects. Thus, the generation of surface defects reduces the ability of the TiO2 surface to adsorb the dye molecules. Heating alone as pre-treatment of the TiO2 substrates instead increases the dye adsorption, without causing detectable defects on the TiO2 surface.

9.
J Chem Phys ; 155(16): 164702, 2021 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-34717368

RESUMO

The properties of semiconductor surfaces can be modified by the deposition of metal clusters consisting of a few atoms. The properties of metal clusters and of cluster-modified surfaces depend on the number of atoms forming the clusters. Deposition of clusters with a monodisperse size distribution thus allows tailoring of the surface properties for technical applications. However, it is a challenge to retain the size of the clusters after their deposition due to the tendency of the clusters to agglomerate. The agglomeration can be inhibited by covering the metal cluster modified surface with a thin metal oxide overlayer. In the present work, phosphine-protected Au clusters, Au9(PPh3)8(NO3)3, were deposited onto RF-sputter deposited TiO2 films and subsequently covered with a Cr2O3 film only a few monolayers thick. The samples were then heated to 200 °C to remove the phosphine ligands, which is a lower temperature than that required to remove thiolate ligands from Au clusters. It was found that the Cr2O3 covering layer inhibited cluster agglomeration at an Au cluster coverage of 0.6% of a monolayer. When no protecting Cr2O3 layer was present, the clusters were found to agglomerate to a large degree on the TiO2 surface.

10.
Angew Chem Int Ed Engl ; 60(13): 7418-7425, 2021 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-33372346

RESUMO

A rational design for oxygen evolution reaction (OER) catalysts is pivotal to the overall efficiency of water electrolysis. Much work has been devoted to understanding cation leaching and surface reconstruction of very active electrocatalysts, but little on intentionally promoting the surface in a controlled fashion. We now report controllable anodic leaching of Cr in CoCr2 O4 by activating the pristine material at high potential, which enables the transformation of inactive spinel CoCr2 O4 into a highly active catalyst. The depletion of Cr and consumption of lattice oxygen facilitate surface defects and oxygen vacancies, exposing Co species to reconstruct into active Co oxyhydroxides differ from CoOOH. A novel mechanism with the evolution of tetrahedrally coordinated surface cation into octahedral configuration via non-concerted proton-electron transfer is proposed. This work shows the importance of controlled anodic potential in modifying the surface chemistry of electrocatalysts.

11.
Angew Chem Int Ed Engl ; 60(39): 21340-21350, 2021 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-34038609

RESUMO

Recently, the creation of new heterogeneous catalysts using the unique electronic/geometric structures of small metal nanoclusters (NCs) has received considerable attention. However, to achieve this, it is extremely important to establish methods to remove the ligands from ligand-protected metal NCs while preventing the aggregation of metal NCs. In this study, the ligand-desorption process during calcination was followed for metal-oxide-supported 2-phenylethanethiolate-protected gold (Au) 25-atom metal NCs using five experimental techniques. The results clearly demonstrate that the ligand-desorption process consists of ligand dissociation on the surface of the metal NCs, adsorption of the generated compounds on the support and desorption of the compounds from the support, and the temperatures at which these processes occurred were elucidated. Based on the obtained knowledge, we established a method to form a metal-oxide layer on the surface of Au NCs while preventing their aggregation, thereby succeeding in creating a water-splitting photocatalyst with high activity and stability.

12.
J Am Chem Soc ; 142(17): 7765-7775, 2020 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-32279490

RESUMO

Exploring efficient and low-cost electrocatalysts for hydrogen evolution reaction (HER) in alkaline media is critical for developing anion exchange membrane electrolyzers. The key to a rational catalyst design is understanding the descriptors that govern the alkaline HER activity. Unfortunately, the principles that govern the alkaline HER performance remain unclear and are still under debate. By studying the alkaline HER at a series of NiCu bimetallic surfaces, where the electronic structure is modulated by the ligand effect, we demonstrate that alkaline HER activity can be correlated with either the calculated or the experimental-measured d band center (an indicator of hydrogen binding energy) via a volcano-type relationship. Such correlation indicates the descriptor role of the d band center, and this hypothesis is further supported by the evidence that combining Ni and Cu produces a variety of adsorption sites, which possess near-optimal hydrogen binding energy. Our finding broadens the applicability of d band theory to activity prediction of metal electrocatalysts and may offer an insightful understanding of alkaline HER mechanism.

13.
J Phys Chem A ; 124(52): 11102-11110, 2020 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-33325710

RESUMO

Ion-surface scattering experiments can be used to measure elemental depth profiles on the angstrom scale in complex liquid mixtures. We employ NICISS (neutral impact collision ion scattering spectroscopy) to measure depth profiles of dissolved ions and solvent in liquid glycerol containing the cationic surfactant tetrahexylammonium bromide (THA+/Br-) at 0.013 M and mixtures of NaBr + NaCl at 0.4 M total concentration. The experiments reveal that Br- outcompetes Cl- in its attraction to surface THA+, and that THA+ segregates more extensively when more Br- ions are present. Intriguingly, the depths spanned by THA+, Br-, and Cl- ions generally increase with Br- bulk concentration, expanding from ∼10 to ∼25 Šfor both Br- and Cl- depth profiles. This broadening likely occurs because of an increasing pileup of THA+ ions in a multilayer region that spreads the halide ions over a wider depth. The experiments indicate that cationic surfactants enhance Br- and Cl- concentrations in the surface region far beyond their bulk-phase values, making solutions coated with these surfactants potentially more reactive toward gases that can oxidize the halide ions.

14.
Pneumologie ; 74(11): 742-749, 2020 Nov.
Artigo em Alemão | MEDLINE | ID: mdl-33202437

RESUMO

The increasing evidence has made it necessary to change international recommendations for the diagnosis and treatment of resistant tuberculosis repeatedly in the recent years. This year, the WHO has published comprehensive recommendations that take into account these developments. The current German tuberculosis guideline was published in 2017 with differing recommendations in some areas. Here the new WHO recommendations of 2020 for rapid diagnosis and therapy of resistant tuberculosis are summarized and the relevant differences are commented for Germany, Austria and Switzerland. A complete re-evaluation of the literature is currently taking place by updating the German-language AWMF 2k guidelines.


Assuntos
Guias de Prática Clínica como Assunto , Tuberculose Resistente a Múltiplos Medicamentos/diagnóstico , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Áustria , Alemanha , Humanos , Suíça , Organização Mundial da Saúde
15.
Lancet Oncol ; 20(3): 339-351, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30795951

RESUMO

BACKGROUND: In postmenopausal women with hormone receptor-positive, early-stage breast cancer, treatment with adjuvant aromatase inhibitors is the standard of care, but it increases risk for osteoporosis and fractures. Results from the ABCSG-18 trial showed that use of denosumab as an adjuvant to aromatase inhibitor therapy significantly reduced clinical fractures. Disease-free survival outcomes from ABCSG-18 have not yet been reported. METHODS: Postmenopausal patients with early, hormone receptor-positive, non-metastatic adenocarcinoma of the breast, who had completed their initial adjuvant treatment pathway (surgery, radiotherapy, or chemotherapy, or a combination) and were receiving adjuvant aromatase inhibitors, were enrolled at 58 trial centres in Austria and Sweden into this prospective, double-blind, placebo-controlled, phase 3 trial. With permuted block randomisation (block sizes 2 and 4, stratified by previous aromatase inhibitor use, total lumbar spine bone mineral density score at baseline, and type of centre), patients were assigned (1:1) to receive subcutaneous denosumab (60 mg) or matching placebo every 6 months during aromatase inhibitor therapy. The primary endpoint (previously reported) was the time to first clinical fracture after randomisation. The secondary endpoint reported here is disease-free survival (defined as time from randomisation to first evidence of local or distant metastasis, contralateral breast cancer, secondary carcinoma, or death from any cause) in the intention-to-treat population. This study is registered with EudraCT (number 2005-005275-15) and ClinicalTrials.gov (number NCT00556374), and is ongoing for long-term follow-up. FINDINGS: Between Dec 18, 2006, and July 22, 2013, 3425 eligible patients were enrolled and randomly assigned; 1711 to the denosumab group and 1709 to the placebo group (with five others withdrawing consent). After a median follow-up of 73 months (IQR 58-95), 240 (14·0%) patients in the denosumab and 287 (16·8%) in the placebo group had disease-free survival events. Disease-free survival was significantly improved in the denosumab group versus the placebo group (hazard ratio 0·82, 95% CI 0·69-0·98, Cox p=0·0260; descriptive analysis, without controlling for multiplicity). In the denosumab group, disease-free survival was 89·2% (95% CI 87·6-90·8) at 5 years and 80·6% (78·1-83·1) at 8 years of follow-up, compared with 87·3% (85·7-89·0) at 5 years and 77·5% (74·8-80·2) and 8 years in the placebo group. No independently adjudicated cases of osteonecrosis of the jaw or confirmed atypical femoral fractures were recorded. The total number of adverse events was similar in the denosumab group (1367 [including 521 serious] adverse events) and the placebo group (1339 [515 serious]). The most common serious adverse events were osteoarthritis (62 [3·6%] of 1709 in the denosumab group vs 58 [3·4%] of 1690 in the placebo group), meniscus injury (23 [1·3%] vs 24 [1·4%]), and cataract (16 [0·9%] vs 28 [1·7%]). One (<0·1%) treatment-related death (due to pneumonia, septic kidney failure, and cardiac decompensation) occurred in the denosumab group. INTERPRETATION: Denosumab constitutes an effective and safe adjuvant treatment for patients with postmenopausal hormone receptor-positive early breast cancer receiving aromatase inhibitor therapy. FUNDING: Amgen.


Assuntos
Inibidores da Aromatase/administração & dosagem , Neoplasias da Mama/tratamento farmacológico , Denosumab/administração & dosagem , Idoso , Inibidores da Aromatase/efeitos adversos , Densidade Óssea/efeitos dos fármacos , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Denosumab/efeitos adversos , Intervalo Livre de Doença , Método Duplo-Cego , Feminino , Humanos , Pessoa de Meia-Idade , Pós-Menopausa/efeitos dos fármacos , Modelos de Riscos Proporcionais , Receptor ErbB-2/genética , Receptores de Estrogênio/genética , Receptores de Progesterona/genética
16.
Langmuir ; 35(44): 14213-14221, 2019 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-31596586

RESUMO

Tethered bilayer lipid membranes are solid supported lipid membranes, where the inner leaflet is covalently linked to the solid supported substrate through anchorlipids. These anchorlipids form a self-assembled monolayer, which serves as the basis of the membrane and also provides submembrane space. The molecular structure and composition of this monolayer has thus significant influence on the membrane structural and functional properties. The density of the self-assembled monolayer can be tailored by adding small molecules to the monolayer. Here, the structure of fully tethered and sparsely tethered monolayers, where the anchorlipid has been diluted with a small surface-active thiol, has been analyzed using neutral impact collision ion scattering spectroscopy, X-ray photoelectron spectroscopy, and metastable induced electron spectroscopy. Combination of these three techniques allowed description of the self-assembly process in detail. The monolayers have been characterized in terms of layer thickness and orientation of the lipids.


Assuntos
Membrana Celular/química , Bicamadas Lipídicas/química , Estrutura Molecular , Espectroscopia Fotoeletrônica
17.
J Chem Phys ; 151(16): 164704, 2019 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-31675867

RESUMO

Titanium dioxide (TiO2) is used to form the anode in dye sensitized solar cells (DSSCs) and is thus one of the crucial components of this type of solar cell. A large range of treatments of the titania anode before deposition of the dye have been applied to improve the performance of DSSCs among which the TiCl4 treatment is the most frequently used treatment. The present study investigates how the TiCl4 treatment of the TiO2 changes the anode. For this purpose, different sample sets, nontreated, post-treated, and pre-post treated cells, were fabricated and analyzed with electron and ion scattering spectroscopy to investigate how they change the titania surface and consequently influence the cell performance. After the TiCl4 treatment, the short circuit current density (Jsc), open-circuit voltage (Voc), and efficiency significantly improved. An upward shift in the conduction band of the semiconductor as an effect of TiCl4 treatment was measured using inverse photoemission spectroscopy and UV-photoelectron spectroscopy. An increase in dye adsorption due to the treatment was found through neutral impact collision ion scattering spectroscopy measurement. The change in the energy level alignment of the titania and the adsorbed dye and the increase in dye loading explain the threefold increase of power conversion of the cells.

18.
Small ; 13(5)2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27860268

RESUMO

A robust solution phase ligand exchange system for lead sulfide (PbS) quantum dots (QDs) in the presence of Pb-thiolate ligands is presented that can better preserve the excitonic absorption and emission features as compared to the conventional ligands. The photoluminescence after ligand exchange of PbS QDs with Pb-thiolate ligand is preserved up to 78% of the original oleate capped PbS QDs.

19.
Lancet Oncol ; 17(9): 1230-9, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27501767

RESUMO

BACKGROUND: The randomised phase 3 TURANDOT trial compared two approved bevacizumab-containing regimens for HER2-negative metastatic breast cancer in terms of efficacy, safety, and quality of life. The interim analysis did not confirm non-inferior overall survival (stratified hazard ratio [HR] 1·04; 97·5% repeated CI [RCI] -∞ to 1·69). Here we report final results of our study aiming to show non-inferior overall survival with first-line bevacizumab plus capecitabine versus bevacizumab plus paclitaxel for locally recurrent or metastatic breast cancer. METHODS: In this multinational, open-label, randomised phase 3 TURANDOT trial, patients aged 18 years or older who had an Eastern Cooperative Oncology Group performance status 0-2 and measurable or non-measurable HER2-negative locally recurrent or metastatic breast cancer who had received no previous chemotherapy for locally recurrent or metastatic breast cancer were stratified and randomly assigned (1:1) using permuted blocks of size six to either bevacizumab plus paclitaxel (bevacizumab 10 mg/kg on days 1 and 15 plus paclitaxel 90 mg/m(2) on days 1, 8, and 15 every 4 weeks) or bevacizumab plus capecitabine (bevacizumab 15 mg/kg on day 1 plus capecitabine 1000 mg/m(2) twice daily on days 1-14 every 3 weeks) until disease progression, unacceptable toxicity, or withdrawal of consent. Stratification factors were oestrogen or progesterone receptor status, country, and menopausal status. The primary objective was to show non-inferior overall survival with bevacizumab plus capecitabine versus bevacizumab plus paclitaxel in the per-protocol population by rejecting the null hypothesis of inferiority (HR ≥1·33) using a stratified Cox proportional hazard model. This trial is registered with ClinicalTrials.gov, number NCT00600340. FINDINGS: Between Sept 10, 2008, and Aug 30, 2010, 564 patients were randomised, representing the intent-to-treat population. The per-protocol population comprised 531 patients (266 in the bevacizumab plus paclitaxel group and 265 in the bevacizumab plus capecitabine group). At the final overall survival analysis after 183 deaths (69%) in 266 patients receiving bevacizumab plus paclitaxel and 201 (76%) in 265 receiving bevacizumab plus capecitabine in the per-protocol population, median overall survival was 30·2 months (95% CI 25·6-32·6 months) versus 26·1 months (22·3-29·0), respectively. The stratified HR was 1·02 (97·5% RCI -∞ to 1·26; repeated p=0·0070), indicating non-inferiority. The unstratified Cox model (HR 1·13 [97·5% RCI -∞ to 1·39]; repeated p=0·061) did not support the primary analysis. Intent-to-treat analyses were consistent with the per-protocol results. The most common grade 3 or worse adverse events were neutropenia (54 [19%] of 284 patients in the bevacizumab plus paclitaxel group vs 5 [2%] of 277 patients in the bevacizumab plus capecitabine group), hand-foot syndrome (1 [<1%] vs 43 [16%]), peripheral neuropathy (39 [14%] vs 1 [<1%]), leucopenia (20 [7%] vs 1 [<1%]), and hypertension (12 [4%] vs 16 [6%]). Serious adverse events were reported in 65 (23%) of 284 patients receiving bevacizumab plus paclitaxel and 68 (25%) of 277 receiving bevacizumab plus capecitabine. Deaths in two (1%) of 284 patients in the bevacizumab plus paclitaxel group were deemed by the investigator to be treatment-related. No treatment-related deaths occurred in the bevacizumab plus capecitabine group. INTERPRETATION: Bevacizumab plus capecitabine represents a valid first-line treatment option for HER2-negative locally recurrent or metastatic breast cancer, offering good tolerability without compromising overall survival compared with bevacizumab plus paclitaxel. Although progression-free survival with the bevacizumab plus capecitabine combination is inferior to that noted with bevacizumab plus paclitaxel, we suggest that physicians should consider possible predictive risk factors for overall survival, individual's treatment priorities, and the differing safety profiles. FUNDING: Roche.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Recidiva Local de Neoplasia/tratamento farmacológico , Qualidade de Vida , Receptor ErbB-2/metabolismo , Idoso , Bevacizumab/administração & dosagem , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Capecitabina/administração & dosagem , Feminino , Seguimentos , Humanos , Metástase Neoplásica , Recidiva Local de Neoplasia/metabolismo , Recidiva Local de Neoplasia/patologia , Estadiamento de Neoplasias , Paclitaxel/administração & dosagem , Prognóstico , Taxa de Sobrevida
20.
Lancet ; 386(9992): 433-43, 2015 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-26040499

RESUMO

BACKGROUND: Adjuvant endocrine therapy compromises bone health in patients with breast cancer, causing osteopenia, osteoporosis, and fractures. Antiresorptive treatments such as bisphosphonates prevent and counteract these side-effects. In this trial, we aimed to investigate the effects of the anti-RANK ligand antibody denosumab in postmenopausal, aromatase inhibitor-treated patients with early-stage hormone receptor-positive breast cancer. METHODS: In this prospective, double-blind, placebo-controlled, phase 3 trial, postmenopausal patients with early hormone receptor-positive breast cancer receiving treatment with aromatase inhibitors were randomly assigned in a 1:1 ratio to receive either denosumab 60 mg or placebo administered subcutaneously every 6 months in 58 trial centres in Austria and Sweden. Patients were assigned by an interactive voice response system. The randomisation schedule used a randomly permuted block design with block sizes 2 and 4, stratified by type of hospital regarding Hologic device for DXA scans, previous aromatase inhibitor use, and baseline bone mineral density. Patients, treating physicians, investigators, data managers, and all study personnel were masked to treatment allocation. The primary endpoint was time from randomisation to first clinical fracture, analysed by intention to treat. As an additional sensitivity analysis, we also analysed the primary endpoint on the per-protocol population. Patients were treated until the prespecified number of 247 first clinical fractures was reached. This trial is ongoing (patients are in follow-up) and is registered with the European Clinical Trials Database, number 2005-005275-15, and with ClinicalTrials.gov, number NCT00556374. FINDINGS: Between Dec 18, 2006, and July 22, 2013, 3425 eligible patients were enrolled into the trial, of whom 3420 were randomly assigned to receive denosumab 60 mg (n=1711) or placebo (n=1709) subcutaneously every 6 months. Compared with the placebo group, patients in the denosumab group had a significantly delayed time to first clinical fracture (hazard ratio [HR] 0·50 [95% CI 0·39-0·65], p<0·0001). The overall lower number of fractures in the denosumab group (92) than in the placebo group (176) was similar in all patient subgroups, including in patients with a bone mineral density T-score of -1 or higher at baseline (n=1872, HR 0·44 [95% CI 0·31-0·64], p<0·0001) and in those with a bone mineral density T-score of less than -1 already at baseline (n=1548, HR 0·57 [95% CI 0·40-0·82], p=0·002). The patient incidence of adverse events in the safety analysis set (all patients who received at least one dose of study drug) did not differ between the denosumab group (1366 events, 80%) and the placebo group (1334 events, 79%), nor did the numbers of serious adverse events (521 vs 511 [30% in each group]). The main adverse events were arthralgia and other aromatase-inhibitor related symptoms; no additional toxicity from the study drug was reported. Despite proactive adjudication of every potential osteonecrosis of the jaw by an international expert panel, no cases of osteonecrosis of the jaw were reported. 93 patients (3% of the full analysis set) died during the study, of which one death (in the denosumab group) was thought to be related to the study drug. INTERPRETATION: Adjuvant denosumab 60 mg twice per year reduces the risk of clinical fractures in postmenopausal women with breast cancer receiving aromatase inhibitors, and can be administered without added toxicity. Since a main side-effect of adjuvant breast cancer treatment can be substantially reduced by the addition of denosumab, this treatment should be considered for clinical practice. FUNDING: Amgen.


Assuntos
Anticorpos Monoclonais Humanizados/uso terapêutico , Neoplasias da Mama/complicações , Fraturas Ósseas , Absorciometria de Fóton , Adulto , Idoso , Idoso de 80 Anos ou mais , Inibidores da Aromatase/uso terapêutico , Áustria , Densidade Óssea/fisiologia , Neoplasias da Mama/tratamento farmacológico , Denosumab , Método Duplo-Cego , Feminino , Fraturas Ósseas/complicações , Fraturas Ósseas/prevenção & controle , Humanos , Pessoa de Meia-Idade , Pós-Menopausa , Estudos Prospectivos , Receptores de Estrogênio/metabolismo , Receptores de Progesterona/metabolismo , Suécia , Resultado do Tratamento
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