First-line atezolizumab plus nab-paclitaxel for unresectable, locally advanced, or metastatic triple-negative breast cancer: IMpassion130 final overall survival analysis.

BACKGROUND: Guidelines recommend atezolizumab plus nab-paclitaxel (A + nP) for first-line treatment of unresectable, locally advanced, or metastatic triple-negative breast cancer expressing programmed death-ligand 1 (PD-L1) on tumor-infiltrating immune cells (IC), based on IMpassion130. We report the final overall survival (OS) and safety of that study as per the prespecified analysis plan. PATIENTS AND METHODS: Patients were randomized to nP 100 mg/m2 (days 1, 8, and 15 of a 28-day cycle) with atezolizumab 840 mg (A + nP) or placebo (P + nP; days 1 and 15), until progression or unacceptable toxicity. Coprimary endpoints were progression-free survival [intention-to-treat (ITT) and PD-L1 IC-positive populations] and OS (tested hierarchically in the ITT population and, if significant, in the PD-L1 IC-positive population). RESULTS: Each arm comprised 451 patients; 666 (73.8%) had died by the final OS analysis cut-off (median follow-up, 18.8 months; interquartile range, 8.9-34.7 months). Median OS in the ITT population was 21.0 months [95% confidence interval (CI), 19.0-23.4 months] with A + nP, and 18.7 months (95% CI, 16.9-20.8 months) with P + nP [stratified hazard ratio (HR), 0.87; 95% CI, 0.75-1.02; P = 0.077]. Exploratory analysis in the PD-L1 IC-positive population showed a median OS of 25.4 months (95% CI, 19.6-30.7 months) with A + nP (n = 185) and 17.9 months (95% CI, 13.6-20.3 months) with P + nP (n = 184; stratified HR, 0.67; 95% CI, 0.53-0.86). Safety outcomes were consistent with previous analyses and the known toxicity profiles of each agent. Immune-mediated adverse events of special interest were reported in 58.7% and 41.6% of patients treated with A + nP and P + nP, respectively. CONCLUSION: Although the OS benefit in the ITT population was not statistically significant, precluding formal testing, clinically meaningful OS benefit was observed with A + nP in PD-L1 IC-positive patients, consistent with prior interim analyses. This combination remained safe and tolerable with longer follow-up.

Primary results from IMpassion131, a double-blind, placebo-controlled, randomised phase III trial of first-line paclitaxel with or without atezolizumab for unresectable locally advanced/metastatic triple-negative breast cancer.

BACKGROUND: In the phase III IMpassion130 trial, combining atezolizumab with first-line nanoparticle albumin-bound-paclitaxel for advanced triple-negative breast cancer (aTNBC) showed a statistically significant progression-free survival (PFS) benefit in the intention-to-treat (ITT) and programmed death-ligand 1 (PD-L1)-positive populations, and a clinically meaningful overall survival (OS) effect in PD-L1-positive aTNBC. The phase III KEYNOTE-355 trial adding pembrolizumab to chemotherapy for aTNBC showed similar PFS effects. IMpassion131 evaluated first-line atezolizumab-paclitaxel in aTNBC. PATIENTS AND METHODS: Eligible patients [no prior systemic therapy or ≥12 months since (neo)adjuvant chemotherapy] were randomised 2:1 to atezolizumab 840 mg or placebo (days 1, 15), both with paclitaxel 90 mg/m2 (days 1, 8, 15), every 28 days until disease progression or unacceptable toxicity. Stratification factors were tumour PD-L1 status, prior taxane, liver metastases and geographical region. The primary endpoint was investigator-assessed PFS, tested hierarchically first in the PD-L1-positive [immune cell expression ≥1%, VENTANA PD-L1 (SP142) assay] population, and then in the ITT population. OS was a secondary endpoint. RESULTS: Of 651 randomised patients, 45% had PD-L1-positive aTNBC. At the primary PFS analysis, adding atezolizumab to paclitaxel did not improve investigator-assessed PFS in the PD-L1-positive population [hazard ratio (HR) 0.82, 95% confidence interval (CI) 0.60-1.12; P = 0.20; median PFS 6.0 months with atezolizumab-paclitaxel versus 5.7 months with placebo-paclitaxel]. In the PD-L1-positive population, atezolizumab-paclitaxel was associated with more favourable unconfirmed best overall response rate (63% versus 55% with placebo-paclitaxel) and median duration of response (7.2 versus 5.5 months, respectively). Final OS results showed no difference between arms (HR 1.11, 95% CI 0.76-1.64; median 22.1 months with atezolizumab-paclitaxel versus 28.3 months with placebo-paclitaxel in the PD-L1-positive population). Results in the ITT population were consistent with the PD-L1-positive population. The safety profile was consistent with known effects of each study drug. CONCLUSION: Combining atezolizumab with paclitaxel did not improve PFS or OS versus paclitaxel alone. CLINICALTRIALS.GOV: NCT03125902.

Visualization of spatial and temporal temperature distributions with magnetic particle imaging for liver tumor ablation therapy.

Temperature-resolved magnetic particle imaging (MPI) represents a promising tool for medical imaging applications. In this study an approach based on a single calibration measurement was applied for highlighting the potential of MPI for monitoring of temperatures during thermal ablation of liver tumors. For this purpose, liver tissue and liver tumor phantoms embedding different superparamagnetic iron oxide nanoparticles (SPION) were prepared, locally heated up to 70 °C and recorded with MPI. Optimal temperature MPI SPIONs and a corresponding linear model for temperature calculation were determined. The temporal and spatial temperature distributions were compared with infrared (IR) camera results yielding quantitative agreements with a mean absolute deviation of 1 °C despite mismatches in boundary areas.

Increasing the sensitivity for stem cell monitoring in system-function based magnetic particle imaging.

The use of superparamagnetic iron oxide nanoparticles (SPIONs) has provided new possibilities in biophysics and biomedical imaging technologies. The magnetization dynamics of SPIONs, which can be influenced by the environment, are of central interest. In this work, different biological SPION environments are used to investigate three different calibration methods for stem cell monitoring in magnetic particle imaging. It is shown that calibrating using SPIONs immobilized via agarose gel or intracellular uptake results in superior stem cell image quality compared to mobile SPIONs in saline. This superior image quality enables more sensitive localization and identification of a significantly smaller number of magnetically labeled stem cells. The results are important for cell tracking and monitoring of future SPION based therapies such as hyperthermia based cancer therapies, targeted drug delivery, or tissue regeneration approaches where it is crucial to image a sufficiently small number of SPIONs interacting with biological matter.

Intracellular mannose binding lectin mediates subcellular trafficking of HIV-1 gp120 in neurons.

Human immunodeficiency virus-1 (HIV-1) enters the brain early during infection and leads to severe neuronal damage and central nervous system impairment. HIV-1 envelope glycoprotein 120 (gp120), a neurotoxin, undergoes intracellular trafficking and transport across neurons; however mechanisms of gp120 trafficking in neurons are unclear. Our results show that mannose binding lectin (MBL) that binds to the N-linked mannose residues on gp120, participates in intravesicular packaging of gp120 in neuronal subcellular organelles and also in subcellular trafficking of these vesicles in neuronal cells. Perinuclear MBL:gp120 vesicular complexes were observed and MBL facilitated the subcellular trafficking of gp120 via the endoplasmic reticulum (ER) and Golgi vesicles. The functional carbohydrate recognition domain of MBL was required for perinuclear organization, distribution and subcellular trafficking of MBL:gp120 vesicular complexes. Nocodazole, an agent that depolymerizes the microtubule network, abolished the trafficking of MBL:gp120 vesicles, suggesting that these vesicular complexes were transported along the microtubule network. Live cell imaging confirmed the association of the MBL:gp120 complexes with dynamic subcellular vesicles that underwent trafficking in neuronal soma and along the neurites. Thus, our findings suggest that intracellular MBL mediates subcellular trafficking and transport of viral glycoproteins in a microtubule-dependent mechanism in the neurons.

Superparamagnetic iron oxide nanoparticles in biomedicine: applications and developments in diagnostics and therapy.

Superparamagnetic iron oxide nanoparticles (SPIO) can be used to image physiological processes and anatomical, cellular and molecular changes in diseases. The clinical applications range from the imaging of tumors and metastases in the liver, spleen and bone marrow, the imaging of lymph nodes and the CNS, MRA and perfusion imaging to atherosclerotic plaque and thrombosis imaging. New experimental approaches in molecular imaging describe undirected SPIO trapping (passive targeting) in inflammation, tumors and associated macrophages as well as the directed accumulation of SPIO ligands (active targeting) in tumor endothelia and tumor cells, areas of apoptosis, infarction, inflammation and degeneration in cardiovascular and neurological diseases, in atherosclerotic plaques or thrombi. The labeling of stem or immune cells allows the visualization of cell therapies or transplant rejections. The coupling of SPIO to ligands, radio- and/or chemotherapeutics, embedding in carrier systems or activatable smart sensor probes and their externally controlled focusing (physical targeting) enable molecular tumor therapies or the imaging of metabolic and enzymatic processes. Monodisperse SPIO with defined physicochemical and pharmacodynamic properties may improve SPIO-based MRI in the future and as targeted probes in diagnostic magnetic resonance (DMR) using chip-based µNMR may significantly expand the spectrum of in vitro analysis methods for biomarker, pathogens and tumor cells. Magnetic particle imaging (MPI) as a new imaging modality offers new applications for SPIO in cardiovascular, oncological, cellular and molecular diagnostics and therapy.

Production dynamics of Withaferin A in Withania somnifera (L.) Dunal complex.

Withaferin A (WA) is an important withanolide holding promise in cancer treatment and as a relatively safe radiosensitive/chemotherapeutic agent, which is present in traces in all parts of Withania somnifera except the leaves, where as it is reported to be present in only two non-Indian chemotypes (South African chemotype/Israel chemotype 1). The present studies have marked its presence in all Indian populations (wild/cultivated), as well as two identified Indian chemotypes (AGB002 and AGB025). The quantitative dynamics of WA production in Indian populations and interchemotypic hybrids developed at our institute have been studied, and the results were compared with five previously reported chemotypes from Israel, South Africa and India. An analysis on inheritance characteristics based on presence/absence of WA in hybrid plants and their respective parents is given for future studies on the chemogenetics of this complex species in greater detail. Further, the production potential of WA in vitro propagated plants of elite varieties developed at our institute is discussed, in view of maintaining chemotypic fidelity and stability from a production point of view. Also, evidence-based clues suggesting the leaves as the site of the synthesis of WA is provided.

Molecular stages of rapid and uniform neuralization of human embryonic stem cells.

Insights into early human development are fundamental for our understanding of human biology. Efficient differentiation of human embryonic stem cells (hESCs) into neural precursor cells is critical for future cell-based therapies. Here, using defined conditions, we characterized a new method for rapid and uniform differentiation of hESCs into committed neural precursor cells (designated C-NPCs). Dynamic gene expression analysis identified several distinct stages of ESC neuralization and revealed functional modules of coregulated genes and pathways. The first wave of gene expression changes, likely corresponding to the transition through primitive ectoderm, started at day 3, preceding the formation of columnar neuroepithelial rosettes. The second wave started at day 5, coinciding with the formation of rosettes. The majority of C-NPCs were positive for both anterior and posterior markers of developing neuroepithelium. In culture, C-NPCs became electrophysiologically functional neurons; on transplantation into neonatal mouse brains, C-NPCs integrated into the cortex and olfactory bulb, acquiring appropriate neuronal morphologies and markers. Compared to rosette-NPCs,(1) C-NPCs exhibited limited in vitro expansion capacity and did not express potent oncogenes such as PLAG1 or RSPO3. Concordantly, we never detected tumors or excessive neural proliferation after transplantation of C-NPCs into mouse brains. In conclusion, our study provides a framework for future analysis of molecular signaling during ESC neuralization.

Efficacy and safety results from the randomized controlled comparative study of adalimumab vs. methotrexate vs. placebo in patients with psoriasis (CHAMPION).

BACKGROUND: Biologic therapies such as adalimumab, a tumour necrosis factor antagonist, are safe and effective in the treatment of moderate to severe chronic plaque psoriasis. OBJECTIVES: To compare a biologic agent with methotrexate, a traditional systemic agent, to define clearly the role of biologics in psoriasis. METHODS: Patients with moderate to severe plaque psoriasis were randomized to adalimumab (80 mg subcutaneously at week 0, then 40 mg every other week, n=108), methotrexate (7.5 mg orally, increased as needed and as tolerated to 25 mg weekly; n=110) or placebo (n=53) for 16 weeks. The primary efficacy endpoint was the proportion of patients achieving at least a 75% improvement in the Psoriasis Area and Severity Index (PASI 75) after 16 weeks. Safety was assessed at all visits through week 16. RESULTS: After 16 weeks, 79.6% of adalimumab-treated patients achieved PASI 75, compared with 35.5% for methotrexate (P<0.001 vs. adalimumab) and 18.9% for placebo (P<0.001 vs. adalimumab). Statistically significantly more adalimumab-treated patients (16.7%) than methotrexate-treated patients (7.3%) or placebo-treated patients (1.9%) achieved complete clearance of disease. The response to adalimumab was rapid, with a 57% improvement in mean PASI observed at week 4. Adverse events were similar across treatment groups. Adverse events leading to study discontinuation were greatest in the methotrexate group, primarily because of hepatic-related adverse events. CONCLUSIONS: After 16 weeks, adalimumab demonstrated significantly superior efficacy and more rapid improvements in psoriasis compared with either methotrexate or placebo.

[Magnetic resonance imaging of single SPIO labeled mesenchymal stem cells at 3 Tesla]. / Magnetresonanz-Bildgebung von einzelnen SPIO-markierten mesenchymalen Stammzellen bei 3 Tesla.

PURPOSE: To assess the detectability of single magnetically labeled mesenchymal stem cells (MSC) in-vitro on a clinical 3T MR scanner using a small animal volume coil. MATERIALS AND METHODS: GFP-transfected MSC were magnetically labeled with superparamagnetic iron oxide particles (SPIO) while applying different dosages of iron (56 vs. 560 microg Fe/ml). The cellular iron content was determined with atomic absorption spectrometry (AAS). Single labeled MSC were displayed in a culture flask using MR imaging and microscopy. Special cell phantoms were designed to examine the detection of labeled MSC with MR imaging in a spatial model. A T2*-weighted 3D gradient echo sequence with isotropic spatial resolution of 150 to 500 microm (3) was used for image acquisition. The detection of labeled MSC in the cell phantoms was quantitatively evaluated using an automated image analysis. Statistical analysis was performed with a significance level of p < 0.05. RESULTS: The labeling of MSC yielded a mean cellular iron content of 1.5 +/- 0.17 pg Fe/cell (56 microg Fe/ml) and 8.3 +/- 1.85 pg Fe/cell (560 microg Fe/ml). Examination of the culture flasks showed single magnetically labeled MSC centered in much larger MR signal voids. The detection and quantification of single MSC in cell phantoms were feasible for spatial resolutions of 150 microm and 200 microm. Cells with a lower SPIO content (1.5 +/- 0.17 pg Fe/cell) were detected in 14.2 +/- 4.2 % (150 microm) and 7.7 +/- 3.8 % (200 microm). MSC with a higher cellular SPIO content (8.3 +/- 1.85 pg Fe/cell) revealed significantly higher occurrences at both spatial resolutions with 81.4 +/- 5.8 % (150 microm) and 59.9 +/- 12.4 % (200 microm), respectively. Regarding the spatial resolution (150 vs. 200 microm), significantly different detection rates were determined only for MSC with the higher SPIO content (8.3 +/- 1.85 pg Fe/cell). CONCLUSION: Detection of single magnetically labeled MSC is feasible on a clinical 3T MR scanner with a small animal volume coil at isotropic spatial resolutions of 150 microm and 200 microm. The number of detected cells is influenced by the cellular iron content and the spatial resolution.

HIV-1 infection and AIDS: consequences for the central nervous system.

Infection with the human immunodeficiency virus-1 (HIV-1) can induce severe and debilitating neurological problems that include behavioral abnormalities, motor dysfunction and frank dementia. After infiltrating peripheral immune competent cells, in particular macrophages, HIV-1 provokes a neuropathological response involving all cell types in the brain. HIV-1 also incites activation of chemokine receptors, inflammatory mediators, extracellular matrix-degrading enzymes and glutamate receptor-mediated excitotoxicity, all of which can trigger numerous downstream signaling pathways and disrupt neuronal and glial function. This review will discuss recently uncovered pathologic neuroimmune and degenerative mechanisms contributing to neuronal damage induced by HIV-1 and potential approaches for development of future therapeutic intervention.

Efficacy and safety of adalimumab as monotherapy in patients with rheumatoid arthritis for whom previous disease modifying antirheumatic drug treatment has failed.

OBJECTIVE: To evaluate the efficacy and safety of monotherapy with adalimumab in patients with RA for whom previous DMARD treatment has failed. METHODS: In a 26 week, double blind, placebo controlled, phase III trial, 544 patients with RA were randomised to monotherapy with adalimumab 20 mg every other week, 20 mg weekly, 40 mg every other week, 40 mg weekly, or placebo. The primary efficacy end point was > or =20% improvement in the ACR core criteria (ACR20 response). Secondary efficacy end points included ACR50, ACR70, EULAR responses, and the Disability Index of the Health Assessment Questionnaire (HAQ DI). RESULTS: After 26 weeks, patients treated with adalimumab 20 mg every other week, 20 mg weekly, 40 mg every other week, and 40 mg weekly had significantly better response rates than those treated with placebo: ACR20 (35.8%, 39.3%, 46.0%, 53.4%, respectively v 19.1%; p< or =0.01); ACR50 (18.9%, 20.5%, 22.1%, 35.0% v 8.2%; p< or =0.05); ACR70 (8.5%, 9.8%, 12.4%, 18.4% v 1.8%; p< or =0.05). Moderate EULAR response rates were significantly greater with adalimumab than with placebo (41.5%, 48.2%, 55.8%, 63.1% v 26.4%; p< or =0.05). Patients treated with adalimumab achieved better improvements in mean HAQ DI than those receiving placebo (-0.29, -0.39, -0.38, -0.49 v -0.07; p< or =0.01). No significant differences were found between adalimumab and placebo treated patients for serious adverse events, serious infections, or malignancies. Injection site reaction occurred in 10.6% and 0.9% of adalimumab and placebo treated patients, respectively (p< or =0.05). CONCLUSION: Among patients with RA for whom previous DMARD treatment had failed, adalimumab monotherapy achieved significant, rapid, and sustained improvements in disease activity and improved physical function and was safe and well tolerated.

Expression of membrane C1q in human monocyte-derived macrophages is developmentally regulated and enhanced by interferon-gamma.

The present study investigated when during "in vitro" maturation macrophages (MPhi) express membrane C1q (mC1q), and whether cell activation affects expression and function of mC1q. Although C1q mRNA was repeatedly detected in freshly isolated monocytes using reverse transcriptase-polymerase chain reaction, C1q protein was observed only in developing MPhi from day 1 to 4 on using immunodetection and flow cytometry. However, the quantity of mC1q and other MPhi membrane proteins differed strikingly in cells from different donors. We report here for the first time that CD14(+) and CD14(-) mC1q-bearing MPhi can develop, and that interferon-gamma increases mC1q display at the cell surface, and mC1q-mediated phagocytosis.

Randomized, placebo-controlled trial of the anti-tumor necrosis factor antibody fragment afelimomab in hyperinflammatory response during severe sepsis: The RAMSES Study.

OBJECTIVE: This study investigated whether treatment with the anti-tumor necrosis factor-alpha monoclonal antibody afelimomab would improve survival in septic patients with serum interleukin (IL)-6 concentrations of >1000 pg/mL. DESIGN: Multicenter, double-blind, randomized, placebo-controlled study. SETTING: Eighty-four intensive care units in academic medical centers in Europe and Israel. PATIENTS: A total of 944 septic patients were screened and stratified by the results of a rapid qualitative immunostrip test for serum IL-6 concentrations. Patients with a positive test kit result indicating IL-6 concentrations of >1000 pg/mL were randomized to receive either afelimomab (n = 224) or placebo (n = 222). Patients with a negative IL-6 test (n = 498) were not randomized and were followed up for 28 days. INTERVENTIONS: Treatment consisted of 15-min infusions of 1 mg/kg afelimomab or matching placebo every 8 hrs for 3 days. Standard surgical and intensive care therapy was otherwise delivered. MEASUREMENTS AND MAIN RESULTS: The study was terminated prematurely after an interim analysis estimated that the primary efficacy end points would not be met. The 28-day mortality rate in the nonrandomized patients (39.6%, 197 of 498) was significantly lower (p <.001) than that found in the randomized patients (55.8%, 249 of 446). The mortality rates in the IL-6 test kit positive patients randomized to afelimomab and placebo were similar, 54.0% (121 of 224) vs. 57.7% (128 of 222), respectively. Treatment with afelimomab was not associated with any particular adverse events. CONCLUSIONS: The IL-6 immunostrip test identified two distinct sepsis populations with significantly different mortality rates. A small (3.7%) absolute reduction in mortality rate was found in the afelimomab-treated patients. The treatment difference did not reach statistical significance.

Pathways to neuronal injury and apoptosis in HIV-associated dementia.

Human immunodeficiency virus-1 (HIV-1) can induce dementia with alarming occurrence worldwide. The mechanism remains poorly understood, but discovery in brain of HIV-1-binding sites (chemokine receptors) provides new insights. HIV-1 infects macrophages and microglia, but not neurons, although neurons are injured and die by apoptosis. The predominant pathway to neuronal injury is indirect through release of macrophage, microglial and astrocyte toxins, although direct injury by viral proteins might also contribute. These toxins overstimulate neurons, resulting in the formation of free radicals and excitotoxicity, similar to other neurodegenerative diseases. Recent advances in understanding the signalling pathways mediating these events offer hope for therapeutic intervention.

An inducible packaging cell system for safe, efficient lentiviral vector production in the absence of HIV-1 accessory proteins.

Lentiviral vectors based on human immunodeficiency virus type 1 (HIV-1) possess the ability to deliver exogenous genes to both dividing and nondividing cells and to subsequently establish a stable provirus in these target cells, which can allow long-term expression of the transferred gene. Herein we describe a stable packaging cell line that is devoid of HIV-1 tat, vif, vpr, vpu, and nef. In order to avoid any risk of cytotoxicity associated with constitutive expression of HIV-1 protease or the VSV-G envelope protein, transcription of the packaging and envelope constructs was tightly controlled by employing the ecdysone-inducible system. Using this cell line, we have been able to consistently generate concentrated pseudotyped vector virus stocks with titers in the range of 10(8) IU/ml, which can efficiently transduce actively dividing and growth-arrested cells in vitro. This novel packaging cell line for lentiviral vectors facilitates the production of high-titer virus stocks in the absence of replication-competent virus and provides us with an important tool for use in future gene transfer studies.

Relationship between interleukin-6 plasma concentration in patients with sepsis, monocyte phenotype, monocyte phagocytic properties, and cytokine production.

Monocyte phenotype, their phagocytic capacity as well as the cytokine production from 10 patients with sepsis with low interleukin-6 (IL-6) serum concentrations (<1000 pg/mL) and 8 patients with sepsis with high IL-6 (> or = 1000 pg/mL) plasma concentrations were investigated within 24 hours of fulfilling the criteria for sepsis. Monocytes from patients with high IL-6 levels had higher levels of human leukocyte antigen (HLA)-DR, HLA-ABC, CD64, and CD71, and the production of tumor necrosis factor-alpha (TNF-alpha) and IL-8, as well as the capacity of monocytes to phagocytose, was significantly elevated. Of 8 patients with high levels of plasma IL-6, 4 patients died. In contrast, all 10 patients with low plasma IL-6 concentrations survived until day 28. Patients who died had constant high IL-6 concentrations during the first 3 days, whereas IL-6 levels in patients who survived decreased by 88%. Our data indicate that IL-6 levels are a better prognostic parameter in the early phase of sepsis than the monocyte HLA-DR expression.

Endothelin in septic patients: effects on cardiovascular and renal function and its relationship to proinflammatory cytokines.

OBJECTIVE: To determine the time course of big-endothelin (big-ET) and its relationship to proinflammatory cytokines and organ function in sepsis. DESIGN: Prospective analysis in patients meeting criteria of severe sepsis as part of a multicenter study (RAMSES) with an anti-tumor necrosis factor monoclonal antibody F(ab')2 fragment (afelimomab). SETTING: University hospital intensive care unit. PATIENTS: A total of 23 nontrauma patients with severe sepsis or septic shock and ten multiple trauma patients. Septic patients were randomized for additional experimental treatment when initial interleukin (IL)-6 serum level was above 1000 pg/mL. INTERVENTIONS: Randomized patients received 1.0 mg/kg afelimomab or placebo three times daily over 3 days in addition to standard treatment. In each patient, serial blood samples for plasma big-ET and cytokine determination as well as clinical data were collected over 28 days. MEASUREMENTS AND MAIN RESULTS: Significantly increased concentrations of circulating big-ET were found in patients with severe sepsis as compared with healthy subjects. In septic patients, big-ET plasma levels were higher than in multiple trauma patients, and were more elevated in randomized than in nonrandomized patients. At study entry (day 0), big-ET reached a peak concentration and significantly correlated with IL-6 (r2 = .43) and IL-8 (r2 = .44) in patients with severe sepsis. Moreover, big-ET levels in septic patients, pooled over all observation days, correlated positively with pressure-adjusted heart rate, central venous pressure, pulmonary artery pressure, and pulmonary vascular resistance and correlated inversely with creatinine clearance (r2 = .54, .54, .59, .40, and .51, respectively, p = .0001). In all randomized septic patients, pressure-adjusted heart rate decreased from day 0 to day 2 in parallel with big-ET; however, a significant decrease in big-ET (day 0 to day 2) was only found in patients additionally treated with afelimomab. CONCLUSIONS: In patients with severe sepsis, big-ET plasma levels are markedly increased, even above those of multiple trauma patients, in close relationship to IL-6 and IL-8, and with significant correlation to renal function and pulmonary vascular tone.