A Mechanistic Systems Pharmacology Model for Prediction of LDL Cholesterol Lowering by PCSK9 Antagonism in Human Dyslipidemic Populations.

PCSK9 is a promising target for the treatment of hyperlipidemia and cardiovascular disease. A Quantitative Systems Pharmacology model of the mechanisms of action of statin and anti-PCSK9 therapies was developed to predict low density lipoprotein (LDL) changes in response to anti-PCSK9 mAb for different treatment protocols and patient subpopulations. Mechanistic interactions and cross-regulation of LDL, LDL receptor, and PCSK9 were modeled, and numerous virtual subjects were developed and validated against clinical data. Simulations predict a slightly greater maximum percent reduction in LDL cholesterol (LDLc) when anti-PCSK9 is administered on statin background therapy compared to as a monotherapy. The difference results primarily from higher PCSK9 levels in patients on statin background. However, higher PCSK9 levels are also predicted to increase clearance of anti-PCSK9, resulting in a faster rebound of LDLc. Simulations of subjects with impaired LDL receptor (LDLR) function predict compromised anti-PCSK9 responses in patients such as homozygous familial hypercholesterolemics, whose functional LDLR is below 10% of normal.

Are surgical trials with negative results being interpreted correctly?

BACKGROUND: Many published accounts of clinical trials report no differences between the treatment arms, while being underpowered to find differences. This study determined how the authors of these reports interpreted their findings. STUDY DESIGN: We examined 54 reports of surgical trials chosen randomly from a database of 110 influential trials conducted in 2008. Seven that reported having adequate statistical power (ß ≥ 0.9) were excluded from further analysis, as were the 32 that reported significant differences between the treatment arms. We examined the remaining 15 to see whether the authors interpreted their negative findings appropriately. Appropriate interpretations discussed the lack of power and/or called for larger studies. RESULTS: Three of the 7 trials that did not report an a priori power calculation offered inappropriate interpretations, as did 3 of the 8 trials that reported an a priori power < 0.90. However, we examined only a modest number of trial reports from 1 year. CONCLUSIONS: Negative findings in underpowered trials were often interpreted as showing the equivalence of the treatment arms with no discussion of the issue of being underpowered. This may lead clinicians to accept new treatments that have not been validated.

Conflicts among multinational ethical and scientific standards for clinical trials of therapeutic interventions.

Utilizing a sorted compendium of international clinical trial standards, investigators identified 15 conflicts among ethical and methodological guidance. Analysis distinguishes interpretational issues, lack of clarity, and contradiction as factors to be addressed if international trial guidance is to be improved.

A taxonomy of multinational ethical and methodological standards for clinical trials of therapeutic interventions.

BACKGROUND: If trials of therapeutic interventions are to serve society's interests, they must be of high methodological quality and must satisfy moral commitments to human subjects. The authors set out to develop a clinical-trials compendium in which standards for the ethical treatment of human subjects are integrated with standards for research methods. METHODS: The authors rank-ordered the world's nations and chose the 31 with >700 active trials as of 24 July 2008. Governmental and other authoritative entities of the 31 countries were searched, and 1004 English-language documents containing ethical and/or methodological standards for clinical trials were identified. The authors extracted standards from 144 of those: 50 designated as 'core', 39 addressing trials of invasive procedures and a 5% sample (N=55) of the remainder. As the integrating framework for the standards we developed a coherent taxonomy encompassing all elements of a trial's stages. FINDINGS: Review of the 144 documents yielded nearly 15 000 discrete standards. After duplicates were removed, 5903 substantive standards remained, distributed in the taxonomy as follows: initiation, 1401 standards, 8 divisions; design, 1869 standards, 16 divisions; conduct, 1473 standards, 8 divisions; analysing and reporting results, 997 standards, four divisions; and post-trial standards, 168 standards, 5 divisions. CONCLUSIONS: The overwhelming number of source documents and standards uncovered in this study was not anticipated beforehand and confirms the extraordinary complexity of the clinical trials enterprise. This taxonomy of multinational ethical and methodological standards may help trialists and overseers improve the quality of clinical trials, particularly given the globalisation of clinical research.

Traditional knowledge and intellectual property.

Biotechnological inventions are sometimes based upon the traditional knowledge of indigenous communities about the beneficial properties of plants and animals. Some institutions have adopted the uniqueness of traditional knowledge approach, which maintains that the indigenous communities have sui generis rights to a share of the profits from these inventions. Others have adopted the protection of inventive steps approach, which maintains that the inventors are entitled to the full profits from the invention if it involves a non-obvious and novel inventive step. The article analyzes this debate at the Convention on Biological Diversity, at the World Intellectual Property Organization, and at the World Trade Organization. It concludes that the adherents of the uniqueness of traditional knowledge approach have not justified their claims.

Intellectual property, state sovereignty, and biotechnology.

The issue of biopiracy has attracted considerable attention in recent years. The Convention on Biological Diversity adopted a principle of state sovereignty over biological resources and the genetic information contained within those resources to address this issue. It is argued that this principle has not been adequately justified and that there are other solutions to the issue of biopiracy, based on different theories of justice, that deserve greater consideration. These alternatives include the common heritage of mankind principle and the global commons principle.

Cell migration to the chemokine CXCL8: paxillin is activated and regulates adhesion and cell motility.

The chemokine CXCL8 is a powerful inducer of directional cell motility, primarily during inflammation. In this study, we found that CXCL8 stimulation led to paxillin phosphorylation in normal neutrophils, and that both CXCL8 receptors (CXCR1 and CXCR2) mediated CXCL8-induced paxillin phosphorylation. In CXCR2-transfected cells, the process depended on G(alphai) and G(alphas) coupling to CXCR2. Dominant negative (DN) paxillin increased CXCL8-induced adhesion and migration, indicating that endogenous paxillin keeps migration at submaximal levels. Furthermore, using activating antibodies to beta1 integrins, analyses with focal adhesion kinase (FAK) DN variant (FRNK) and co-immunoprecipitations of FAK and paxillin, we found that beta1 integrin ligation cooperates with CXCL8-induced stimulation, leading to FAK activation and thereafter to FAK-mediated paxillin phosphorylation. Our findings indicate that paxillin keeps directional motility at a restrained magnitude, and suggest that perturbations in its activation may lead to chemotactic imbalance and to pathological conditions associated with excessive or reduced leukocyte migration.

The multifaceted roles of chemokines in malignancy.

Tumor development and progression are multifactorial processes, regulated by a large variety of intrinsic and microenvironmental factors. A key role in cancer is played by members of the chemokine superfamily. Chemokines and their receptors are expressed by tumor cells and by host cells, in primary tumors and in specific metastatic loci. The effects of chemokines on tumorigenesis are diverse: While some members of the superfamily significantly support this process, others inhibit fundamental events required for tumor establishment and metastasis. The current review describes the multifaceted roles of chemokines in malignancy, addressing four major aspects of their activities: (1) inducing leukocyte infiltration to tumors and regulating immune functions, with emphasis on tumor-associated macrophages (and the chemokines CCL2, CCL5), T cells (and the chemokines CXCL9, CXCL10) and dendritic cells (and the chemokines CCL19, CCL20, CCL21); (2) directing the homing of tumor cells to specific metastatic sites (the CXCL12-CXCR4 axis); (3) regulating angiogenic processes (mainly the ELR(+)-CXC and non-ELR-CXC chemokines); (4) acting directly on the tumor cells to control their malignancy-related functions. Together, these different chemokine functions establish a net of interactions between the tumor cells and their microenvironment, and partly dictate the fate of the malignancy cascade.

Inflammation-associated immune suppression in cancer: the roles played by cytokines, chemokines and additional mediators.

Chronic inflammation and presence of inflammatory cells, primarily macrophages, at tumor sites are highly associated with specific malignancies. In these cases, the inflammatory milieu is overloaded with mediators that suppress immune activities at many levels: recognition of tumor-associated antigens, activation, the actual cytolysis of tumor cells and more. Local suppression of leukocyte functions at the inflammatory tumor site further contributes to profound immunosuppression of potential anti-tumor immune functions. The present review discusses the inflammatory setup in tumors and the factors inducing the presence of detrimental inflammatory macrophages at tumor sites. Moreover, the different mediators that contribute to inflammation-associated immune suppression, including primarily cytokines and chemokines but also prostaglandins and oxidants, are described. Bearing in mind the notion that under specific conditions the inflammatory mediators clearly contribute to malignancy, while in others they may exert surveillance missions against tumor cells, the potential therapeutic value of the inflammatory components is discussed.

Is the use of placebo controls ethically permissible in clinical trials of agents intended to reduce fractures in osteoporosis?

Substantial progress has been made in developing treatments that reduce the risk of fractures in osteoporosis. However, available treatments are only partially effective, they are not widely used, and there is need to search for more effective means of fracture prevention. Currently known effective means of reducing fractures were found using randomized placebo-controlled trials. The use of placebo controls in clinical trials has been a subject of significant controversy in recent years. The Declaration of Helsinki revision of October 2000 caused great concern among clinical investigators about the future use of placebo controls if known effective therapeutic agents are available. A working group of ethicists, clinical trial design experts, and clinical investigators examined the current state of knowledge of osteoporosis treatment and trials. They concluded that if placebo controls put subjects at substantial risk of serious outcomes, they are not ethically permissible. Placebo controls in osteoporosis trials with fracture as the measured outcome are permissible only under narrowly defined conditions. Placebo controls may be used if competent, well-informed patients refuse approved therapies for sound reasons, there is a reasonable basis for substantial disagreement or lack of consensus among professionals about whether approved treatments are better than placebos, or subjects are refractory to known effective agents. Active control trials are permissible and desirable if they can be designed and conducted in ways that overcome the interpretive difficulties often associated with such trials.

Host microenvironment in breast cancer development: inflammatory cells, cytokines and chemokines in breast cancer progression: reciprocal tumor-microenvironment interactions.

A comprehensive overview of breast cancer development and progression suggests that the process is influenced by intrinsic properties of the tumor cells, as well as by microenvironmental factors. Indeed, in breast carcinoma, an intensive interplay exists between the tumor cells on one hand, and inflammatory cells/cytokines/chemokines on the other. The purpose of the present review is to outline the reciprocal interactions that exist between these different elements, and to shed light on their potential involvement in breast cancer development and progression.

Ethical issues in clinical trials in developing countries.

The vertical transmission trials conducted in a variety of developing countries by researchers from more developed countries illustrate a variety of crucial ethical issues. Three crucial issues are the injustice of the use of placebo control groups, the coerciveness of the offer to participate, and the exploitation of Third World countries. This paper examines each of these issues separately. It develops a new standard for when such control groups are acceptable. It concludes that the issue of coercive offers is not well founded. It also concludes that concerns about exploitation are better addressed by assurances about the future care of the subjects in the trial than by assurances of availability of the drugs in the country in general.

A controlled trial of arthroscopic surgery for osteoarthritis of the knee.

BACKGROUND: Many patients report symptomatic relief after undergoing arthroscopy of the knee for osteoarthritis, but it is unclear how the procedure achieves this result. We conducted a randomized, placebo-controlled trial to evaluate the efficacy of arthroscopy for osteoarthritis of the knee. METHODS: A total of 180 patients with osteoarthritis of the knee were randomly assigned to receive arthroscopic débridement, arthroscopic lavage, or placebo surgery. Patients in the placebo group received skin incisions and underwent a simulated débridement without insertion of the arthroscope. Patients and assessors of outcome were blinded to the treatment-group assignment. Outcomes were assessed at multiple points over a 24-month period with the use of five self-reported scores--three on scales for pain and two on scales for function--and one objective test of walking and stair climbing. A total of 165 patients completed the trial. RESULTS: At no point did either of the intervention groups report less pain or better function than the placebo group. For example, mean (+/-SD) scores on the Knee-Specific Pain Scale (range, 0 to 100, with higher scores indicating more severe pain) were similar in the placebo, lavage, and débridement groups: 48.9+/-21.9, 54.8+/-19.8, and 51.7+/-22.4, respectively, at one year (P=0.14 for the comparison between placebo and lavage; P=0.51 for the comparison between placebo and débridement) and 51.6+/-23.7, 53.7+/-23.7, and 51.4+/-23.2, respectively, at two years (P=0.64 and P=0.96, respectively). Furthermore, the 95 percent confidence intervals for the differences between the placebo group and the intervention groups exclude any clinically meaningful difference. CONCLUSIONS: In this controlled trial involving patients with osteoarthritis of the knee, the outcomes after arthroscopic lavage or arthroscopic débridement were no better than those after a placebo procedure.

Noncompliance with medical follow-up after pediatric intensive care.

OBJECTIVES: To describe the medical follow-up ordered, the health care utilization, the appointment compliance, and the risk factors associated with noncompliance in patients who are discharged after a pediatric intensive care unit (PICU) stay. METHODS: A prospective, analytic, cohort study of 111 critically ill children, age 1 day to 16 years, who were admitted to a 30-bed PICU in an urban, tertiary-care, pediatric teaching hospital compared children who were compliant with medical follow-up with those who were not. The main outcomes measured were emergent and unscheduled physician visits during the first 6 weeks after hospital discharge; compliance with ordered medical follow-up after hospital discharge; and comparisons of socioeconomic, demographic, and medical need factors between compliant and noncompliant children. Discharge orders for follow-up appointments with general pediatricians and subspecialists were collected from the chart at hospital discharge. Patients were contacted after hospital discharge to determine whether and when they received medical follow-up; 28% were found to be noncompliant. Risk factors associated with noncompliance were evaluated. Emergent and unscheduled physician visits were tracked during the first 6 weeks after hospital discharge. RESULTS: Lack of follow-up orders at hospital discharge did not affect the frequency of emergent visits. Children fell into 2 groups: those who were 100% compliant and those with < or =67% compliance. No socioeconomic or demographic risk factors could be identified between the 2 groups. Compared with the 100% compliant patients, patients who were compliant with < or =67% of appointments were more severely ill, as defined by higher peak pediatric risk of mortality scores during their PICU stay (11.5 vs 8.4), longer PICU length of stays (10.1 days vs 4.6 days), and longer hospital length of stays (25.5 days vs 14 days). Most predictive of noncompliance was the number of medical appointments ordered by physicians. Patients with 3 or more appointments were less likely to be compliant with follow-up. After hospital discharge, children were more likely to visit a primary care physician compared with a subspecialist (95% vs 82%). When patients were ordered to see a specialist, scheduled appointments were much better attended than the recommended appointments (92% vs 67%). CONCLUSIONS: Lack of ordered medical follow-up did not affect emergent visits. In this group of critically ill children, a significant percentage (28%) did not receive timely medical follow-up. No socioeconomic or demographic risk factors were identified in noncompliant children. However, severity of illness (higher peak pediatric risk of mortality score, longer PICU stay, and longer hospital stay) and the number of follow-up appointments ordered were predictors of noncompliance. Potential exists for implementing strategies to improve compliance in identified populations.

Possible co-regulation of genes associated with enhanced progression of mammary adenocarcinomas.

Tumor progression is a multistep process in which alterations in the expression of numerous gene products may give rise to highly malignant cellular variants. In the present study, we analyzed the differential expression of several genes in cellular variants of mammary adenocarcinomas with high or low malignancy potential, which originated in a common ancestor. To assess the generality of our findings, high and low malignancy variants were derived from two different mammary adenocarcinoma cell lines, namely DA3 and CSML cells. Of major importance is the fact that the differences between high- and low-malignancy variants observed in one system of mammary adenocarcinoma cells (DA3 cells) were identically reproduced in the other system of mammary adenocarcinoma cells (CSML cells). The high malignancy variants of tumors both DA3-high and CSML-high (previously called CSML-100), expressed higher levels of factors that induce monocyte migration than the low malignancy DA3-low and CSML-low (previously called CSML-0) variants. In addition, it was found that DA3-high and CSML-high cell variants expressed higher levels of monocyte chemoattractant protein-1 (MCP-1), interleukin-6 (IL-6) and matrix metalloproteinases (MMPs) than the low malignancy variants (DA3-low and CSML-low). These results suggest that MCP-1, IL-6 and MMPs potentially contribute to mammary adenocarcinoma progression and that their expression is regulated by a common pathway. The expression of MCP-1, IL-6 and MMPs in both DA3-high and CSML-high cells was up-regulated by tumor necrosis factor alpha (TNFalpha). The fact that TNFalpha exerted similar effects on the expression of these three factors in both cell systems raises the possibility of a coordinated co-regulation of tumor-promoting factors.