Power comparisons for group sequential tests with nonparametric statistics in case of nonproportional hazards.

abstract：:Multiple testing problems in regulatory applications are often more challenging than the problems of handling a set of mathematical symbols representing multiple null hypotheses under testing. In the union-intersection setting, it is important to define a family of null hypotheses relevant to the clinical questions at...

journal_title：Journal of biopharmaceutical statistics

authors： Hung HM,Wang SJ

更新日期：2009-01-01 00:00:00

abstract：:We would like to estimate the parameters of a dose-response function with the greatest precision as possible. For a two-parameter model, this is equivalent to minimizing the area of the confidence ellipsoid, i.e., a D-optimal design. Previous work on this particular model has included minimal designs. These designs ar...

journal_title：Journal of biopharmaceutical statistics

authors： Lupinacci PJ,Raghavarao D

更新日期：2000-02-01 00:00:00

abstract：:Sample size calculation based on normal approximations is often associated with the loss of statistical power for a single-arm trial with a time-to-event endpoint. Recently, Wu (2015) derived the exact variance for the one-sample log-rank test under the alternative and showed that a single-arm one-stage study based on...

journal_title：Journal of biopharmaceutical statistics

authors： Shan G

更新日期：2020-09-02 00:00:00

abstract：:The aim of this work is to quantitatively assess the impact of structural model misspecifications on the estimates of mean and interindividual variability of clearance in the context of population approaches. This assessment is conducted from simulated datasets. Our results show that impact magnitude of model misspeci...

journal_title：Journal of biopharmaceutical statistics

authors： Merlé Y,Aouimer A,Tod M

更新日期：2004-02-01 00:00:00

abstract：:We propose an adaptive two-stage dose-response design where a prespecified adaptation rule is used to add and/or drop treatment arms between the stages. We extend the multiple comparison procedures-modeling (MCP-Mod) approach into a two-stage design. In each stage, we use the same set of candidate dose-response models...

journal_title：Journal of biopharmaceutical statistics

authors： Franchetti Y,Anderson SJ,Sampson AR

更新日期：2013-01-01 00:00:00

abstract：:Multiple comparisons are commonly seen in clinical trials and many other fields. An example, which is the focus of this paper, is the comparison of several test treatments (possibly different doses of a compound) with placebo (control). It is well known that steps must be taken to control the type I error rate when mu...

journal_title：Journal of biopharmaceutical statistics

authors： Chen M,Kianifard F

更新日期：1997-07-01 00:00:00

abstract：:The United States Pharmacopeia (USP) content uniformity sampling acceptance plan consisting of a two-stage sampling plan with criteria on sample mean and number of out-of-range tablets is the standard for compendium. It is, however, often used mistakenly for lot quality assurance. In comparison to the Japan Phamacopei...

journal_title：Journal of biopharmaceutical statistics

authors： Tsong Y,Shen M

更新日期：2007-01-01 00:00:00

abstract：:Large sample size imbalance is not uncommon in the biosimilar development. At the beginning of a product development, sample sizes of a biosimilar and a reference product may be limited. Thus, a sample size calculation may not be feasible. During the development stage, more batches of reference products may be added a...

journal_title：Journal of biopharmaceutical statistics

authors： Dong XC,Weng YT,Tsong Y

更新日期：2017-01-01 00:00:00

abstract：:We extend the development of the expression of the Fisher information matrix in nonlinear mixed effects models for designs evaluation. We consider the dependence of the marginal variance of the observations with the mean parameters and assume an heteroscedastic variance error model. Complex models with interoccasions ...

journal_title：Journal of biopharmaceutical statistics

authors： Retout S,Mentré F

更新日期：2003-05-01 00:00:00

abstract：:The ICH E14 guidance (ICH, 2005) recommend that a concurrent positive control should be included in a thorough QTc clinical trial to validate the study. The ICH E14 guidance (ICH, 2005) state that "The positive control should have an effect on the mean QTc interval of about 5 ms (i.e., an effect that is close to the Q...

journal_title：Journal of biopharmaceutical statistics

authors： Zhang J

更新日期：2008-01-01 00:00:00

abstract：:In recent years, development of biosimilar products has attracted considerable attention. Because of the structural complexity of biologics, it is difficult to demonstrate that a biosimilar product is identical to the reference product. Therefore, for the development of biosimilar products, we need to adopt an approac...

journal_title：Journal of biopharmaceutical statistics

authors： Nagasaki M,Ando Y

更新日期：2014-01-01 00:00:00

abstract：:For administrative convenience or cost efficiency, we may often employ a cluster randomized trial (CRT), in which randomized units are clusters of patients rather than individual patients. Furthermore, because of ethical reasons or patient's decision, it is not uncommon to encounter data in which there are patients no...

journal_title：Journal of biopharmaceutical statistics

authors： Lui KJ,Chang KC

更新日期：2011-01-01 00:00:00

abstract：:Randomized controlled clinical trials often use a composite endpoint as a primary endpoint especially when treatment effects or frequency of individual components of the composite are likely to be small and combining them makes clinical sense for the disease under study. An advantage of the composite endpoint is that,...

journal_title：Journal of biopharmaceutical statistics

authors： Huque MF,Alosh M,Bhore R

更新日期：2011-07-01 00:00:00

abstract：:There is no consensus on determination of sample size in phase II clinical trials. The use of Bayesian decision theory has been proposed by Stallard (1), among others. In this article, optimal three-stage designs are obtained using decision theory. These are compared with procedures proposed by Schoenfeld (2), Ensign ...

journal_title：Journal of biopharmaceutical statistics

authors： Stallard N

更新日期：1998-07-01 00:00:00

abstract：:The Youden index, a main summary index for the receiver operating characteristic (ROC) curve, is a comprehensive measurement for the effectiveness of a diagnostic test. For a continuous-scale diagnostic test, the optimal cut point for positive disease is the cut point leading to the maximization of the sum of sensitiv...

journal_title：Journal of biopharmaceutical statistics

authors： Zhou H,Qin G

更新日期：2012-01-01 00:00:00

abstract：:An integral part of routine health checkups involves laboratory measurements on various analytes in the blood. It is then common to compare the value of two consecutive measurements sampled at different times from the same patient. A "significant" change requires an action (additional sample and/or clinical action). T...

journal_title：Journal of biopharmaceutical statistics

authors： Cohen A,Doveh E,Umansky T

更新日期：2001-01-01 00:00:00

abstract：:Recently, a design was proposed for the Simultaneous Global Drug Development Program (SGDDP) to assess the impact of ethnic factors on the effect of a new treatment for a targeted ethnic (TE) population. It used weighted Z tests to combine the information collected from the TE and non-TE (NTE) subgroups in the SGDDP b...

journal_title：Journal of biopharmaceutical statistics

authors： Liu K,Yuan Z,Chen G,Huang Q,Wenrich J

更新日期：2015-01-01 00:00:00

abstract：:Analyses of multicenter trials consider the estimated treatment effect differences of the individual centers and combine them into an estimate of the overall treatment effect. There has been much debate in the literature concerning the best way to combine these treatment effect differences. We emphasize that first of ...

journal_title：Journal of biopharmaceutical statistics

authors： Dragalin V,Fedorov V,Jones B,Rockhold F

更新日期：2001-11-01 00:00:00

abstract：:A statistic, W, for measuring change from baseline is developed. Its distribution is found. Simulations using W and analysis of covariance (ANCOVA) are run and the results are compared. W is found to be less powerful than ANCOVA, yet is not seen to suffer some of the ill effects to which ANCOVA can fall prey, namely b...

journal_title：Journal of biopharmaceutical statistics

authors： Donahue RM

更新日期：1997-05-01 00:00:00

abstract：:ETRANK is a statistical software which uses nonparametric (randomization) technique to analyze incomplete repeated measures data, where the pattern of withdrawal is treatment related. This stand alone program is written in C, presently runs in MS-DOS, and a Windows version is in development. The program has been devel...

journal_title：Journal of biopharmaceutical statistics

authors： Entsuah R

更新日期：1996-11-01 00:00:00

abstract：:The adverse events data of randomized clinical trials are often analyzed based on either crude incidence rates or exposure-adjusted incidence rates. These rates do not adequately account for an individual patient's profile of adverse events over the study period when an individual may remain in the trial after experie...

journal_title：Journal of biopharmaceutical statistics

authors： Siddiqui O

更新日期：2009-09-01 00:00:00

abstract：:Bowker's test, a generalization of McNemar's test, performs well under the hypothesis of symmetry, but the estimator of variance used in the test is biased when the table is asymmetric and this calls into question the test's performance in non-null situations. We seek an alternative to Bowker's test in search of metho...

journal_title：Journal of biopharmaceutical statistics

authors： May WL,Johnson WD

更新日期：2001-02-01 00:00:00

abstract：:An adaptive enrichment design is a randomized trial that allows enrollment criteria to be modified at interim analyses, based on a preset decision rule. When there is prior uncertainty regarding treatment effect heterogeneity, these trial designs can provide improved power for detecting treatment effects in subpopulat...

journal_title：Journal of biopharmaceutical statistics

authors： Fisher A,Rosenblum M,Alzheimer’s Disease Neuroimaging Initiative.

更新日期：2018-01-01 00:00:00

abstract：:The gold standard for evaluating treatment efficacy of a medical product is a placebo-controlled trial. However, when the use of placebo is considered to be unethical or impractical, a viable alternative for evaluating treatment efficacy is through a noninferiority (NI) study where a test treatment is compared to an a...

journal_title：Journal of biopharmaceutical statistics

authors： Gamalo-Siebers M,Gao A,Lakshminarayanan M,Liu G,Natanegara F,Railkar R,Schmidli H,Song G

更新日期：2016-01-01 00:00:00

abstract：:Using multistage adaptive group sequential test designs, the investigator may perform data-driven changes in the design during the course of the trial without inflation of the Type I error rate. This is possible, for example, through the use of the inverse normal method of combining the p-values from the separate stag...

journal_title：Journal of biopharmaceutical statistics

authors： Wassmer G

更新日期：2003-11-01 00:00:00

abstract：:The concept of quality by design (QbD) as published in ICH-Q8 is currently one of the most recurrent topics in the pharmaceutical literature. This guideline recommends the use of information and prior knowledge gathered during pharmaceutical development studies to provide a scientific rationale for the manufacturing p...

journal_title：Journal of biopharmaceutical statistics

authors： Lebrun P,Giacoletti K,Scherder T,Rozet E,Boulanger B

更新日期：2015-01-01 00:00:00

abstract：:We studied the sensitivity of the number of unique design points and their placement, in Bayesian optimal designs for pharmacokinetic models, with respect to the magnitude of prior uncertainty. We used two and three-parameter pharmacokinetic models with fixed and mixed effects and two Bayesian optimal design criteria,...

journal_title：Journal of biopharmaceutical statistics

authors： Dokoumetzidis A,Aarons L

更新日期：2007-01-01 00:00:00

abstract：:Classification measures play essential roles in the assessment and construction of classifiers. Hence, determining how to prevent these measures from being affected by individual observations has become an important problem. In this paper, we propose several indexes based on the influence function and the concept of l...

journal_title：Journal of biopharmaceutical statistics

authors： Ke BS,Chiang AJ,Chang YI

更新日期：2018-01-01 00:00:00

abstract：:We address the issue of analysis of clinical data generated by the bridging study conducted in the new region to evaluate the similarity for extrapolation of the foreign clinical data. A bridging study is usually conducted in the new region only after the test product is approved for commercial marketing in the origin...

journal_title：Journal of biopharmaceutical statistics

authors： Liu JP,Hsiao CF,Hsueh H

更新日期：2002-08-01 00:00:00

abstract：:The issue of consistency and reliability arises frequently in applied clinical trials, and there is a considerable amount of literature on this topic. For a continuous random variable, we describe a process to assess whether the mean and variance are the same from one evaluation to the other and we derive the intracla...

journal_title：Journal of biopharmaceutical statistics

authors： Kao TC,Sparling Y,Rochon J

更新日期：2003-08-01 00:00:00