安慰剂和阳性药对照的三臂非劣效临床试验的样本含量估计和统计推断

目的 介绍一种基于非劣效界值为标准对照药效应一部分的三臂非劣效临床试验的样本含量估计和统计检验的方法.方法 在介绍Pigeot法的基础上,实例探讨了如何计算样本含量及确定非劣效界值,并用模拟的方法比较了Pigeot法与传统检验方法的检验效能.结果 相同样本含量时Pigeot法的检验效能更高.结论 Pigeot法充分利用了所有样本量的信息,提高了检验效率,降低了临床试验的成本.     

基于相对度量指标的非劣效界值计算方法的比较

目的美国FDA在其非劣效临床试验指南中提供了两种基于相对度量指标的非劣效界值计算方法,一种是与绝对度量指标非劣效界值计算方法相对应的对数转换法(简称对数转换法),另外一种是直接基于相对风险的计算方法(简称直接计算法)。本文探讨了这两种方法计算结果的差异,以评估该差异对非劣效试验结果的影响。方法以风险比(hazard ratio,HR)为例,指代阳性对照药与安慰剂的疗效差异的保守估计值,从计算公式上阐述两种方法的关系,并展示两种方法在高优与低优指标中计算得到的非劣效界值的差异。结果当HR在0.80~1.25时,两种方法计算得到的非劣效界值差别在1%以内;当HR越远离1,差别越大。当取相同的效应保留比例f时,直接计算法计算出的非劣效界值总大于对数转换法,此时会导致低优指标使用直接计算法计算出的界值相对更激进,而高优指标则相对保守。当设定相同的非劣效界值δ时,对于低优指标,使用直接计算法所需设定的效应保留比例f高于对数转换法,对于高优指标则相反。结论在以相对度量指标作为主要评价指标的非劣效试验中,研究者应该认识到这两种计算方法对非劣效界值设定和试验结论的影响,综合考虑临床实践和试验药物的获益-风险等,慎重选取非劣效界值。     

率的非劣效试验中样本含量的估计——SAS和PASS实现

目的 提供二分类定性资料平行设计非劣效临床试验样本含量最常用的计算公式及其 SAS和PASS过程,并为相关参数的设置提供参考。方法 基于二项分布的正态近似理论推导样本含量的估计公式,通过SAS程序和PASS过程探讨各重要参数（样本率、非劣效界值）变化时样本含量及检验效能的变化情况。结果 对率的非劣效试验样本含量的计算,公式、SAS程序和PASS过程能得到一致结果;当检验水准和对照组样本率确定时,试验组样本率越大、检验效能越小、界值越大,所需样本含量越小。结论 利用本文提供的公式、SAS程序和PASS过程,可以帮助研究者系统快速得到二分类资料2组平行非劣效设计时的样本含量。试验组样本率、检验效能和非劣效界值是非劣效临床试验估计样本含量必须认真考虑的参数。     

普鲁卡因青霉素G阻断梅毒母婴垂直传播的等效性和非劣效性评价

目的：对普鲁卡因青霉素G治疗妊娠梅毒，阻断梅毒垂直传播及改善妊娠结局等临床疗效进行等效性和非劣效性评价，为临床提供指导。方法：严格按纳入和排除标准，纳入研究对象145例，随机分组，完成临床观察者共129例，其中普鲁卡因青霉素G组61例，苄星青霉素G组68例。采用随机对照设计，以苄星青霉素G为阳性对照药物，观察普鲁卡因青霉素G治疗妊娠梅毒的有效性并进行等效性和非劣效性检验。结果：非劣效性界值占取对照组各率的20％，进行单侧u检验；以梅毒垂直传播有效阻断率为评价指标时，u=25794，u〉δ且P=0.0049，有统计学意义；以正常出生率为评价指标时，u=1．7793，u〉δ且P=0．0376，有统计学意义。等效性界值δ取对照组各率的20％，进行双单侧u检验（two one-side u test）；以梅毒垂直传播有效阻断率为评价指标时，u1=3．1031，u2=2．5794，即u1和u2均大于δ，且P1=0．0010，P2=0．0049，有统计学意义。以正常出生率为评价指标时，u1=2，4866，u2=1．7793，即u1和u2均大于δ，且P1=0．0064，P2=0.0376，P2〉0．025，无统计学意义。结论：本研究表明，以梅毒垂直传播有效阻断率为评价指标，普鲁卡因青霉素G治疗妊娠梅毒与苄星青霉素G等效。以正常出生率为评价指标时，普鲁卡因青霉素G治疗妊娠梅毒非劣效于苄星青霉素G，但是，尚不能认为普鲁卡因青霉素G与苄星青霉素G等效。     

临床新药试验中非劣效性检验界值的确定方法

非劣效性试验中试验药物与公认药物疗效差别的最大允许范围被定义为非劣效性界值(noninferioritymargin),通常用Δ来表示。临床判断非劣效性的一个重要问题是非劣效性界值标准的选择。ICHE10指导原则及CPMP对非劣效性界值标准的确定均提供了一个基本的指导原则〔1,2〕,但缺乏统     

非劣效抗肿瘤药物临床试验样本量的估算

非劣效抗肿瘤药物临床试验在新药的开发和临床推广应用中具有重要作用,其样本量的估算是临床试验的关键环节。本研究中,结合相关文献,按不同的分析和评价指标（计量指标、计数指标、生存分析）,结合实例探讨需要考虑的效应量和统计特征,以及样本量的估算过程。非劣效抗肿瘤药物临床试验样本量的估算,首先要明确非劣效界值,然后根据临床试验涉及的不同分析和评价指标确定相应的效应量,选择相匹配的统计特征,才能准确估算样本量。临床试验中,足够的样本量是提高试验科学性和研究结果准确性的重要条件之一。     

临床试验配对二项数据基于率比的非劣效性/等效性评价

在新药及医疗器械的临床试验中，经常会遇到采用阳性对照、以率作为主要指标，需要对两组率之间非劣效性／等效性进行评价的情形，关于两个独立组率之间非劣效性／等效性评价的统计学方法已有较多介绍，但是对于配对二项数据两组率之间的非劣效性／等效性评价统计学方法的研究和应用还不是很多。文献报道中，配对二项数据两组率间的非劣效性／等效性评价的界值可基于三种测量：率差、率比和比数比。     

非劣效性临床试验中两组率差值的协变量调整方法

目的 解决新药非劣效性临床试验评价中两组率差值的协变量调整问题.方法 利用ROC曲线与两组率差值的对应关系,通过ROC分析间接得到调整协变量之后两组率之差的估计值及标准误.结果 给出了一种新的非参数分层分析方法,如果协变量对有效率有影响,可以通过调整分析得到更准确的检验结果.结论 本文提供的方法能够更直观、有效地对新药临床试验的数据进行非劣效性评价.     

PASS软件实现临床试验中非劣效、等效和优效性检验的样本量估算

用PASS 11软件对非劣效、等效和优效性设计的临床试验进行样本量估算,并与SAS软件运行结果进行比较,探讨PASS 11软件在临床科研中计算样本量的实用性和准确性,为科研工作者在临床试验设计阶段进行科学的样本量估算提供帮助。     

三臂非劣效性设计生存时间数据的半参数统计推断方法

目的 推荐并改进一种用于新药临床试验中生存分析三臂非劣效性设计的半参数统计推断方法.方法 采用Cox比例风险模型建立用于生存时间数据的三臂非劣效检验方法,通过模拟试验验证该方法的有效性,并给出样本含量估计的R语言程序.结果 模拟试验结果证实,在样本删失风险率维持在一定水平时,三臂Cox模型能有效地控制Ⅰ类错误发生概率,并保证较高的检验效能,实际应用简单有效.结论 本文推荐的方法,可以有效地应用于三臂生存时间数据的非劣效性研究.     

PRECIS研究进展

随机对照试验(RCT)可分为评估效力的解释性试验和评估临床效果的实用性临床试验(PCT)。PCT反映了临床实际条件下的干预效应,具有一定的外推性,但其内部真实性相对较差。与此相反,解释性试验是在理想条件下进行,其内部真实性较好,而外推性较差。但在RCT实际设计中,PCT和解释性试验并不是截然分离的两个极端,有许多RCT同时兼有两种设计的属性。PRECIS通过评价RCT设计的解释和实用两方面,指导如何实行干预和试验设计,使RCT在内部和外部真实性之间达到平衡。目前国内对PRECIS介绍甚少,更未见应用的报道,基于此以下介绍PRECIS基本原理、特点及应用,以期为临床试验设计提供参考。     

PRECIS-2:基于研究目标的试验设计

采用随机对照试验（RCT）评价的干预措施效果，涉及理论疗效和实际的临床效果两方面。PRECIS（Pragmatic-Explanatory Continuum Indicator Summary）通过评价RCT设计的解释性和实用性两方面的程度，指导研究者如何实行干预和试验设计，使RCT在内部真实性和外部真实性之间达到一个平衡。在临床试验方案设计过程中，PRECIS的作用逐渐被研究者所认同。为了确保试验的设计与结果相关联，便于患者、临床医生和政策决策者应用，国际多团队专家对PRECIS进行了修正和升级，提出了新的PRECIS-2。PRECIS-2的9个维度都是为了帮助试验设计者思考研究设计的预期效果与试验结果的一致性和特定场景的适用性。本文旨在介绍PRECIS-2的研发、基本原理、特点及应用，以期为国内临床试验设计、决策提供帮助。     

组群随机试验在伤寒疫苗效果观察中的应用研究

目的用组群随机试验实现伤寒Vi疫苗效果观察的研究设计和实施应用。方法采用组群随机试验方法确定试验组和对照组所需样本量，并组织实施大规模疫苗接种，在试验组接种伤寒Vi疫苗、对照组接种流脑疫苗。结果根据组群随机试验方法计算共需要观察对象为96121人，分为108个组群。根据组群大小、地理位置(城乡)及性质(学校、机关、厂矿、人口特征)分层配对，确定试验组分为53个组群共44054人，对照组为54个组群共48422人。对两组间各主要混杂因子(年龄、性别、居住地点、主要人群的经济收入、受教育程度、主要职业)等进行分析，发现两组之间总体相差不大，具有较好的均衡性与可比性。结论组群随机抽样法应用于大规模疫苗效果观察试验，能较好地控制组间混杂因子，使干预的实际效果得到科学的评价；实施也比较简单，被干预对象容易接受，可行性高。     

Randomized cohort trial was shown to be feasible for evaluating treatments in low back pain

ObjectiveTo investigate the feasibility of conducting a cohort, factorial randomized controlled trial (RCT) in the treatment of patients with low back pain (LBP).Study Design and SettingPragmatic feasibility factorial RCT nested within an observational cohort study in two general practices in York, United Kingdom.ResultsEight hundred forty-five patients aged between 18 and 65 years who had consulted their general practitioner about LBP within the preceding 12 months were mailed an invitation to participate in a cohort trial, with the possibility of later joining a treatment RCT. One hundred twenty-four patients consented to participate in the cohort and treatment trial, and one consented only to the cohort only. Ultimately, 59 patients were randomized into the nested RCT. Outcomes included recruitment, acceptability, and attrition rates as measures of the feasibility of the design and Roland Morris Disability Questionnaire. No statistically significant differences in outcome between treatment groups and usual care were found.ConclusionsThe design was feasible for the evaluation of different back pain treatments. We found zero attrition after randomization and showed that for a remitting relapsing condition, the design allows us to recruit initially ineligible patients from the cohort. Additional statistical analysis using regression discontinuity can also be used with this design.     

Study control,violators, inclusion criteria and defining explanatory and pragmatic trials

Important differences between explanatory and pragmatic studies were originally argued by Schwartz and Lellouch. Three important differences between the two types of study involve study control, study violators and inclusion criteria. It was originally argued that explanatory studies are highly controlled, and pragmatic studies may be looser and more like 'real life'. It was argued that an explanatory study should only analyse those receiving treatment, and a pragmatic study would analyse all randomized patients. Explanatory trials are said to use homogeneous groups, and pragmatic studies have less selection (better generalizability). Some suggestions are put forward to update the original distinctions between these two attitudes for future study design. Poor study control is undesirable (but might be necessary) and should not be welcomed as pragmatic. The intention-to-treat strategy is now considered as standard for nearly all trials. Homogeneity is a red herring for studies in humans. Inclusion criteria should be minimized and they should not be used to justify claims of representativeness. Routine criticism of randomized controlled trials for being unrepresentative is unwarranted. We should accept that most trials in humans are 'explanatory'. The division line should be moved, so that pragmatic studies are in the domain of non-therapeutics and complex treatments.     

Evaluating therapy in cerebral palsy

Summary The optimal design for most clinical trials of treatment is the randomized controlled group trial. This methodology is not, however, uniformly applicable or appropriate. The evaluation of physiotherapy in the management of cerebral palsy in childhood is a good example of treatment for which modification of this trial design is needed. Some of the problems with eight studies in this field published between 1960 and 1993 are reviewed here and an alternative approach proposed. A representative series of single case studies with individual goal setting and a validated outcome measurement, using randomized treatment, would overcome many of the disadvantages of published studies at a greatly reduced cost. The results would enable more effective group trials to be mounted in due course to evaluate the probable impact of providing treatment to a defined population of subjects.     

我国医疗器械注册审批中临床试验管理研究

我国医疗器械注册审批中,因临床试验而影响注册审批速度。通过与欧美医疗器械临床试验比较,总结我国医疗器械在临床试验中存在的一些问题并以具体实例加以分析,提出解决我国临床试验问题的相关建议。     

A simulation-free approach to assessing the performance of the continual reassessment method

The continual reassessment method (CRM) is an adaptive design for Phase I trials whose operating characteristics, including appropriate sample size, probability of correctly identifying the maximum tolerated dose, and the expected proportion of participants assigned to each dose, can only be determined via simulation. The actual time to determine a final “best” design can take several hours or days, depending on the number of scenarios that are examined. The computational cost increases as the kernel of the one-parameter CRM design is expanded to other settings, including additional parameters, monitoring of both toxicity and efficacy, and studies of combinations of two agents. For a given vector of true DLT probabilities, we have developed an approach that replaces a simulation study of thousands of hypothetical trials with a single simulation. Our approach, which is founded on the consistency of the CRM, very accurately reflects the results produced by the simulation study, but does so in a fraction of time required by the simulation study. Relative to traditional simulations, we extensively examine how our method is able to assess the operating characteristics of a CRM design for a hypothetical trial whose characteristics are based upon a previously published Phase I trial. We also provide a metric of nonconsistency and demonstrate that although nonconsistency can impact the operating characteristics of our method, the degree of over- or under-estimation is unpredictable. As a solution, we provide an algorithm for maintaining the consistency of a chosen CRM design so that our method is applicable for any trial.     

Adherence to Ketogenic and Mediterranean Study Diets in a Crossover Trial: The Keto–Med Randomized Trial

Adherence is a critical factor to consider when interpreting study results from randomized clinical trials (RCTs) comparing one diet to another, but it is frequently not reported by researchers. The purpose of this secondary analysis of the Keto–Med randomized trial was to provide a detailed examination and comparison of the adherence to the two study diets (Well Formulated Ketogenic Diet (WFKD) and Mediterranean Plus (Med-Plus)) under the two conditions: all food being provided (delivered) and all food being obtained by individual participants (self-provided). Diet was assessed at six time points including baseline (×1), week 4 of each phase when participants were receiving food deliveries (×2), week 12 of each phase when participants were preparing and providing food on their own (×2), and 12 weeks after participants completed both diet phases and were free to choose their own diet pattern (×1). The adherence scores for WFKD and Med-Plus were developed specifically for this study. Average adherence to the two diet patterns was very similar during both on-study time points of the intervention. Throughout the study, a wide range of adherence was observed among participants—for both diet types and during both the delivery phase and self-provided phase. Insight from this assessment of adherence may aid other researchers when answering the important question of how to improve behavioral adherence during dietary trials. This study is registered at clinicaltrials.gov {"type":"clinical-trial","attrs":{"text":"NCT03810378","term_id":"NCT03810378"}}NCT03810378.