On the COLTON Model for Clinical Trials with Delayed Observations-Dichotomous Responses

In the COLTON model for clinical trials a choice is to be made between two medical treatments where there is a known patient horizon N. In an earlier paper we studied the COLTON model under the additional assumption that there is a time lag between the administration of the treatments and the availability of the responses where the responses are normally distributed. Here we extend the results of the earlier paper to the case where responses are dichotomous. The relative performance of two simple procedures for dealing with the patients who arrive during the waiting period between the end of the administration of treatment in the trial phase and observation of the final trial response is discussed within a BAYESIAN framework.     

Conditional Markov Chain Design for Accrual Clinical Trials

Randomization in a comparative experiment has, as one aim, the control of bias in the initial selection of experimental units. When the experiment is a clinical trial employing the accrual of patients, two additional aims are the control of admission bias and control of chronologic bias. This can be accomplished by using a method of randomization, such as the “biased coin design” of Efron, which sequentially forces balance. As an extension of Efron's design, this paper develops a class of conditional Markov chain designs. The detailed randomization employed utilizes the sequential imbalances in the treatment allocation as states in a Markov process. Through the use of appropriate transition probabilities, a range of possible designs can be attained. An additional objective of physical randomization is to provide a model for data analysis. Such a randomization theoretic analysis is presented for the current designs. In addition, Monte Carlo sampling results are given to support the proposed normal theory approximation to the exact randomization distribution.     

Stopping Rules for Clinical Trials Implicitly Incorporating Safety Information

Clinical trials research is mainly conducted for the purpose of evaluating the relative efficacy of two or more treatments. However, a positive response due to treatment is not sufficient to put forward a new product because one must also demonstrate safety. In such cases, clinical trials which show a positive effect would need to accrue enough patients to also demonstrate that the new treatment is safe. It is our purpose to show how the efficacy and safety problems can be combined to yield a more practical clinical trial design. In this paper we propose an asymmetric stopping rule which allows the experimenter to terminate a clinical trial early for a sufficiently negative result and to continue to a specified number of patients otherwise. As it turns out, a few interim tests will have negligible effects on the overall significance level.     

临床试验进展：生物标志物助推临床开发决策

生物标志物对于疾病的鉴定、早期诊断和预防,以及治疗过程中的监控具有重要作用。寻找和发现有价值的生物标志物已成为目前研究的一个热点。汤森路透Cortellis 临床试验情报将生物标志物的发现与针对当前常见疾病的相关临床试验关联,提供描绘临床图景关键元素和当前趋势的专家分析,从而指导临床开发决策。     

临床试验进展：大数据方法在临床试验中的应用

药物研发的复杂性与日俱增,而大数据时代的到来使得临床试验的进展大大加快。本期“临床试验进展”讨论了皮肤病学新创试验中面向数据的亮点,探讨了现实采用的大数据方法,剖析了对风险导向监察的新兴方法学。此外还汇总了银屑病和特应性皮炎新疗法的临床研究报告,揭示了这些疾病的影响以及Ⅱ期和Ⅲ期研究中已经取得成功的候选药。     

临床试验进展: 适应性设计及透明性

临床试验中的适应性设计是根据累积信息来修正试验的一种设计方法,旨在使临床试验和临床开发计划效率更高,并为患者提供更加有效的治疗。此外,因信息隐匿造成试验失败和患者死亡,从而导致公众对医药行业的信任度下降,故关于公开临床数据的观点已开始朝着提升透明度方向调整。介绍3 类适应性设计方法的特点和应用,以及国外药政部门和制药企业对提高临床试验透明性的举措。     

临床试验进展：临床数据与实验室质量管理规范

将临床研究数据用于临床日常规范及健康相关决策的制定对于改善全球医疗保健至关重要。汤森路透Cortellis 临床试验情报对临床试验数据的应用价值及各国临床实验室质量管理规范的实施情况进行了介绍,提供描绘临床图景关键元素和当前趋势的专家分析,从而指导临床开发决策。     

The Case For Randomized Clinical Trials on the Treatment of Obesity

Some say that randomized clinical trials on weight loss are unnecessary (“the benefits are ‘obvious’”) and others say that such trials are not feasible because too few participants will succeed in maintaining weight loss. Although the intermediate term benefits of weight loss are beyond dispute (lowering of blood pressure, lipids, blood sugar, etc), there is no proof that these benefits will translate into long term benefits, i.e., lower rates of cardiovascular disease and/or lower overall mortality. While this extrapolation may seem obvious, the clinical trials' literature is full of unexpected, adverse side effects of theoretically appealing therapies (e.g., higher mortality with clofibrate and higher cardiovascular disease rates with estrogen treatment in men). Although there is clearly a voluntary component to food ingestion, there are also powerful physiological forces at work which impact on energy balance. For example, individuals of similar height and weight may nevertheless have widely different daily energy expenditures and hence energy requirements. It has been shown in Pima Indians that those with low energy expenditure (i.e., those who are “fuel efficient”) are more prone to future weight gain than those with high energy expenditure. Also, reduced obese individuals have lower 24-hour energy expenditure than individuals who are spontaneously at the same lean weight It appears that this deficit in energy expenditure may last for several years, if not longer, implying that reduced obese individuals must exercise far greater vigilance over their caloric intake than their spontaneously lean peers. If they allow themselves to ingest the same number of calories as the latter, they are likely to regain weight, thereby exposing themselves to charges of overeating, even though their caloric intake does not exceed that of the spontaneously lean!. Epidemiologic data do not support a benefit of weight loss. Populations such as Mexican Americans, among whom obesity is more common than in the general population, do not have excess mortality past age 45. Life expectancy in the U.S. has improved steadily since the early 1970s, despite a rising prevalence of obesity. Lastly, prospective studies have suggested that people who lose weight die at a higher rate than those who maintain a stable weight. This effect persists even after controlling for latent, subclinical disease and cigarette smoking. Although none of the above considerations prove that voluntary weight loss is bad, they indicate that this treatment should lose its hitherto privileged status and be subjected to the rigors of clinical trials as have been treatments for hypercholesterolemia and hypertension.     

药物基因组学在新药临床试验及个体化用药中的应用

药物安全性和有效性评价是药物临床试验和个体化用药的核心,也是药物基因组学研究的主要内容。药物基因组学研究贯穿于药物 研发、上市评价和临床应用整个过程, 根据药物代谢酶、转运体、受体相关基因多态性对用药者进行分层分析,评价与药物体内的处置过程、 安全性、有效性个体差异的相关性。综述药物基因组学在新药临床试验、个体化用药中的应用研究新进展。     

Incorporating Prior Beliefs in Treatment Allocation for Clinical Trials

Recently Faraggi and Reiser (1991) introduced a general dynamic treatment allocation scheme which incorporates the permuted block allocation procedure and the Begg Iglewicz procedure as special cases. A drawback of previous allocation methods is that they did not allow incorporation of prior knowledge of the relative importance of the prognostic factors. In this paper we extend our allocation model to incorporate the weighting of prognostic factors. A simulation study examines the effects of this procedure and an example of its implementation is given.     

医院临床信息模型建立的研究

长期以来,信息的标准化问题一直是我国医院信息化发展的瓶颈。医院信息化建设需要解决的核心问题是医疗信息资源共享,而医疗信息共享的水平和程度从根本上说依赖于统一的标准,特别是临床信息标准。建立一个好的临床信息模型是卫生信息的一项重要工作,就医院临床信息模型进行了研究。     

Randomization Modelling of the Crossover Experiment for Clinical Trials

The two-period cross-over experiment for clinical trials has been examined by several writers following a Gaussian linear model approach. Some authors have expressed interest in the “derivation of the finite permutation model” and have pointed out that the randomization approach to modeling the two-period cross-over design “would highlight the importance of randomizing the subjects to the two groups as a basis for inference”. However, in the literature, there is no development of the randomization approach to this important design. In this paper, after a statement of the experimental design and formulation of the observation random variables of the finite population, two additive randomization models—one with residual effects, the other without—which are the analogues of Grizzle's Gaussian models, are derived. Statistical inference is developed for these randomization models and the results are compared with those of the corresponding Gaussian models. Also, exact inference based upon Fischer's approach is presented.     

Two Stage Sampling for Simultaneously Testing Main and Side Effects in Clinical Trials

In clinical trials for the comparison of two treatments it seems reasonable to stop the study if either one treatment has worked out to be markedly superior in the main effect, or one to be severely inferior with respect to an adverse side effect. Two stage sampling plans are considered for simultaneously testing a main and side effect, assumed to follow a bivariate normal distribution with known variances, but unknown correlation. The test procedure keeps the global significance level under the null hypothesis of no differences in main and side effects. The critical values are chosen under the side condition, that the probability for ending at the first or second stage with a rejection of the elementary null hypothesis for the main effect is controlled, when a particular constellation of differences in mean holds; analogously the probability of ending with a rejection of the null hypotheses for the side effect, given certain treatment differences, is controlled too. Plans “optimal” with respect to sample size are given.     

我国仿制药人体生物等效性临床试验研究室建设的现状与发展路径

我国开展仿制药一致性评价最主要的困难之一是临床试验资源不足,解决办法是考虑将生物等效性临床试验资格认定调整为备案 管理。因此,对备案的医疗机构建设生物等效性试验研究室是一个潜在的挑战。文章分析了国内当前具备生物等效性 / I期临床资质的 机构、分布、承担项目能力及生物等效性临床试验机构、药物分析实验室和合同研究组织之间的关系等,对仿制药生物等效性临床试验 研究室的建设内容和规模展开讨论,供业内及监管部门参考。     

Enumeration of Major Peripheral Blood Leukocyte Populations for Multicenter Clinical Trials Using a Whole Blood Phenotyping Assay

Cryopreservation of peripheral blood leukocytes is widely used to preserve cells for immune response evaluations in clinical trials and offers many advantages for ease and standardization of immunological assessments, but detrimental effects of this process have been observed on some cell subsets, such as granulocytes, B cells, and dendritic cells ^1-3. Assaying fresh leukocytes gives a more accurate picture of the in vivo state of the cells, but is often difficult to perform in the context of large clinical trials. Fresh cell assays are dependent upon volunteer commitments and timeframes and, if time-consuming, their application can be impractical due to the working hours required of laboratory personnel. In addition, when trials are conducted at multiple centers, laboratories with the resources and training necessary to perform the assays may not be located in sufficient proximity to clinical sites. To address these issues, we have developed an 11-color antibody staining panel that can be used with Trucount tubes (Becton Dickinson; San Jose, CA) to phenotype and enumerate the major leukocyte populations within the peripheral blood, yielding more robust cell-type specific information than assays such as a complete blood count (CBC) or assays with commercially-available panels designed for Trucount tubes that stain for only a few cell types. The staining procedure is simple, requires only 100 μl of fresh whole blood, and takes approximately 45 minutes, making it feasible for standard blood-processing labs to perform. It is adapted from the BD Trucount tube technical data sheet (version 8/2010). The staining antibody cocktail can be prepared in advance in bulk at a central assay laboratory and shipped to the site processing labs. Stained tubes can be fixed and frozen for shipment to the central assay laboratory for multicolor flow cytometry analysis. The data generated from this staining panel can be used to track changes in leukocyte concentrations over time in relation to intervention and could easily be further developed to assess activation states of specific cell types of interest. In this report, we demonstrate the procedure used by blood-processing lab technicians to perform staining on fresh whole blood and the steps to analyze these stained samples at a central assay laboratory supporting a multicenter clinical trial. The video details the procedure as it is performed in the context of a clinical trial blood draw in the HIV Vaccine Trials Network (HVTN).     

An Asymptotically Optimal Adaptive Selection Procedure in the Proportional Hazards Model with Conditionally Independent Censoring

Assume k independent populations are given which are distributed according to R, …,R (ϑ_i ∈ Θ ⊆ R ). Taking samples of size n the population with the smallest ϑ-value is to be selected. Using the framework of Le Cam's decision theory (Le Cam , 1986; Strasser , 1985) under mild regularity assumptions, an asymptotically optimal selection procedure is derived for the sequence of localized models. In the proportional hazards model with conditionally independent censoring, an asymptotically optimal adaptive selection procedure is constructed by substituting the unknown nuisance parameter by a kernel estimator.     

Clinical applications of dendritic cell vaccination in the treatment of cancer

Dendritic cell (DC) immunotherapy has shown significant promise in animal studies as a potential treatment for cancer. Its application in the clinic depends on the results of human trials. Here, we review the published clinical trials of cancer immunotherapy using exogenously antigen-exposed DCs. We begin with a short review of general properties and considerations in the design of such vaccines. We then review trials by disease type. Despite great efforts on the part of individual investigative groups, most trials to date have not yielded data from which firm conclusions can be drawn. The reasons for this include nonstandard DC preparation and vaccination protocols, use of different antigen preparations, variable means of immune assessment, and nonrigorous criteria for defining clinical response. While extensive animal studies have been conducted using DCs, optimal parameters in humans remain to be established. Unanswered questions include optimal cell dose, use of mature versus immature DCs for vaccination, optimal antigen preparation, optimal route, and optimal means of assessing immune response. It is critical that these questions be answered, as DC therapy is labor- and resource-intensive. Cooperation is needed on the part of the many investigators in the field to address these issues. If such cooperation is not forthcoming, the critical studies that will be required to make DC therapy a clinically and commercially viable enterprise will not take place, and this therapy, so promising in preclinical studies, will not be able to compete with the many other new approaches to cancer therapy presently in development. Trials published in print through June 2003 are included. We exclude single case reports, except where relevant, and trials with so many variables as to prevent interpretation about DC therapy effects.