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Journal of Biopharmaceutical Statistics

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https://www.readbyqxmd.com/read/28166468/dose-finding-designs-for-trials-of-molecularly-targeted-agents-and-immunotherapies
#1
Cody Chiuzan, Jonathan Shtaynberger, Gulam A Manji, Jimmy K Duong, Gary K Schwartz, Anastasia Ivanova, Shing M Lee
Recently, there has been a surge of early phase trials of molecularly targeted agents (MTAs) and immunotherapies. These new therapies have different toxicity profiles compared to cytotoxic therapies. MTAs can benefit from new trial designs that allow inclusion of low-grade toxicities, late-onset toxicities, addition of an efficacy endpoint, and flexibility in the specification of a target toxicity probability. To study the degree of adoption of these methods, we conducted a Web of Science search of articles published between 2008 and 2014 that describe phase 1 oncology trials...
February 6, 2017: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/28166466/choosing-a-covariate-adaptive-randomization-procedure-in-practice
#2
Maroussa Zagoraiou
Pocock and Simon's minimization method is a very popular covariate-adaptive randomization procedure intended to balance the allocations of two treatments across a set of covariates without compromising randomness. Additional covariate-adaptive schemes have been proposed in the literature, such as Atkinson's DA-optimum Biased Coin Design and the Covariate-Adaptive Biased Coin Design (CA-BCD), and their properties were analyzed and compared in terms of imbalance and predictability. The aim of this paper is to push forward these comparisons by taking also into account other randomization methods, such as the Permuted Block Design and the Big Stick Design, a generalization of the CA-BCD that can be implemented when the covariate distribution is unknown, and the Covariate-Adaptive Dominant Biased Coin Design, which is a new class of stratified randomization methods that forces the balance increasingly as the joint imbalance grows and improves the degree of randomness as the size of every stratum increases...
February 6, 2017: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/28166460/an-evaluation-of-increasing-sample-size-based-on-conditional-power
#3
Michael Gaffney, James H Ware
We evaluate properties of sample size re-estimation (SSR) designs similar to the promising zone design considered by Mehta and Pocock (2011). We evaluate these designs under the assumption of a true effect size of 1.1 down to 0.4 of the protocol specified effect size by six measures: 1. The probability of a sample size increase; 2. The mean proportional increase in sample size given an increase; 3 and 4. The mean true conditional power with and without a sample size increase; 5 and 6. The expected increase in sample size and power due to the SSR procedure...
February 6, 2017: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/28166459/a-bayesian-paradigm-for-decision-making-in-proof-of-concept-trials
#4
Erik Pulkstenis, Kaushik Patra, Jianliang Zhang
Decision making is central to every phase of drug development, and especially at the Proof of Concept stage where risk and evidence must be weighed carefully, often in the presence of significant uncertainty. The decision to proceed or not to large expensive Phase 3 trials has significant implications to both patients and sponsors alike. Recent experience has shown that Phase 3 failure rates remain high. We present a flexible Bayesian quantitative decision making paradigm that evaluates evidence relative to achieving a multilevel target product profile...
February 6, 2017: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/28166457/sample-size-re-estimation-and-other-mid-course-adjustments-with-sequential-parallel-comparison-design
#5
Rachel K Silverman, Anastasia Ivanova
Sequential parallel comparison design (SPCD) was proposed to reduce placebo response in a randomized trial with placebo comparator. Subjects are randomized between placebo and drug in stage 1 of the trial and then placebo non-responders are re-randomized in stage 2. Efficacy analysis includes all data from stage 1 and all placebo non-responding subjects from stage 2. This article investigates the possibility to re-estimate the sample size and adjust the design parameters, allocation proportion to placebo in stage 1 of SPCD and weight of stage 1 data in the overall efficacy test statistic, during an interim analysis...
February 6, 2017: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/28166456/the-likelihood-ratio-test-for-the-hill-model
#6
Yifang Li, Russell Reeve
The Hill model is used to describe many biological phenomena to describe the dose-response relationship in clinical trials, and other applications. When testing the null hypothesis of no curve versus the Hill model, the likelihood ratio test (LRT) does not exhibit the appropriate Type I error rate. We describe the reason for the failure of the LRT, and then proceed to show that a chi-squared approximation with about 1.6 degrees of freedom works well. We then extend the results to analyses of data from published literature...
February 6, 2017: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/28156184/benefit-risk-assessment-methods-in-medical-product-development-1-st-edition
#7
William Wang, Sammy Yuan
No abstract text is available yet for this article.
February 3, 2017: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/28060570/adjustment-for-unbalanced-sample-size-for-analytical-biosimilar-equivalence-assessment
#8
Xiaoyu Cassie Dong, Yu-Ting Weng, Yi Tsong
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 at a later stage to have a more reliable estimate of the reference variability. On the other hand, we also need a sufficient number of biosimilar batches in order to have a better understanding of the product...
January 6, 2017: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/28055327/exact-test-based-approach-for-equivalence-test-with-parameter-margin
#9
Xiaoyu Cassie Dong, Yuanyuan Bian, Yi Tsong, Tianhua Wang
The equivalence test has a wide range of applications in pharmaceutical statistics which we need to test for the similarity between two groups. In recent years, the equivalence test has been used in assessing the analytical similarity between a proposed biosimilar product and a reference product. More specifically, the mean values of the two products for a given quality attribute are compared against an equivalence margin in the form of ±f × σR, where ± f × σ R is a function of the reference variability...
January 5, 2017: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/28051920/on-the-establishment-of-equivalence-acceptance-criterion-in-analytical-similarity-assessment
#10
Tongrong Wang, Shein-Chung Chow
For the assessment of biosimilarity of biosimilar products, the United States (US) Food and Drug Administration (FDA) proposed a stepwise approach for providing the totality-of-the-evidence of similarity between a proposed biosimilar product and a US-licensed (reference) product. The stepwise approach starts with the assessment of critical quality attributes (CQAs) that are relevant to clinical outcomes in structural and functional characterization in the manufacturing process of the proposed biosimilar product...
January 4, 2017: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/28026996/on-hybrid-parallel-crossover-designs-for-assessing-drug-interchangeability-of-biosimilar-products
#11
Shein-Chung Chow, Fuyu Song, Can Cui
In recent years, a specific hybrid parallel-crossover design that consists of two sequences of treatments, namely R-R-R-R and R-T-R-T, where T and R is a proposed biosimilar product and an innovative biological product, respectively, have been proposed and received much attention for assessing drug interchangeability between T and R, where R could be either a US-licensed product or an EU-reference product. In practice, there are three types of hybrid parallel-crossover designs that are commonly employed in assessing drug interchangeability of biosimilar products...
December 27, 2016: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/28010186/graphical-aids-for-visualizing-and-interpreting-patterns-in-departures-from-agreement-in-ordinal-categorical-observer-agreement-data
#12
Shrikant I Bangdiwala
When studying the agreement between two observers rating the same n units into the same k discrete ordinal categories, Bangdiwala (1985) proposed using the 'agreement chart' to visually assess agreement. This paper proposes that often it is more interesting to focus on the patterns of disagreement and visually understanding the departures from perfect agreement. We review the use of graphical techniques for descriptively assessing agreement and disagreements, and also review some of the available summary statistics that quantify such relationships...
December 23, 2016: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/28010168/bayesian-analysis-of-piecewise-growth-mixture-models-with-skew-t-distributions-application-to-aids-studies
#13
Getachew A Dagne, Boubakari Ibrahimou
A major problem in HIV/AIDS studies is the development of drug resistance to antiretroviral (ARV) drug or therapy. Estimating the time at which such drug resistance would develop is usually sought. The goal of this article is to perform this estimation by developing growth mixture models with change-points and skew-t distributions based on longitudinal data. For such data, following ARV treatment, the profile of each subject's viral load tends to follow a 'broken stick' like growth trajectory, indicating multiple phases of decline and increase in viral loads...
December 23, 2016: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/28001483/bayesian-isotonic-regression-dose-response-bird-model
#14
Wen Li, Haoda Fu
Understanding dose-response relationship is a crucial step in drug development. There are a few parametric methods to estimate dose-response curves, such as the Emax model and the logistic model. These parametric models are easy to interpret and, hence, widely used. However, these models often require the inclusion of patients on high-dose levels; otherwise, the model parameters cannot be reliably estimated. To have robust estimation, nonparametric models are used. However, these models are not able to estimate certain important clinical parameters, such as ED50 and Emax...
December 21, 2016: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/27977326/development-of-statistical-methods-for-analytical-similarity-assessment
#15
Yi Tsong, Xiaoyu Dong, Meiyu Shen
To evaluate the analytical similarity between the proposed biosimilar product and the US-licensed reference product, a working group at Food and Drug Administration (FDA) developed a tiered approach. This proposed tiered approach starts with a criticality determination of quality attributes (QAs) based on risk ranking of their potential impact on product quality and the clinical outcomes. Those QAs characterize biological products in terms of structural, physico-chemical, and functional properties. Correspondingly, we propose three tiers of statistical approaches based on its levels of stringent in requirements...
December 15, 2016: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/27977325/guest-editor-s-note-special-issue-on-biosimilarity-assessment
#16
Victoria Yu-Wei Chang, Laszlo Endrenyi
No abstract text is available yet for this article.
December 15, 2016: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/27977324/special-issue-of-journal-of-biopharmaceutical-statistics-dedicated-to-2016-trends-and-innovations-in-clinical-trial-statistics-ticts-conference
#17
Marie Davidian, Anastasia Ivanova, Olga Marchenko
No abstract text is available yet for this article.
December 15, 2016: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/27960624/efficient-estimation-in-two-stage-randomized-clinical-trials-using-ranked-sets
#18
Syed Shahadat Hossain, Nabil Awan
Clinical trials designed for survival probability estimation of different treatment policies for chronic diseases like cancer, leukemia, and schizophrenia usually need randomization of treatments in two stages. Since complete remission is rare for these diseases, initially an induction therapy is given for patient's remission. Further treatment, which is often an expensive maintenance therapy, is administered only for the patients with remission. If the maintenance therapy is so expensive that the cost of the trial inflates, only a simple random sample of patients will be treated with the expensive maintenance due to budget constraint...
December 14, 2016: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/27937121/statistical-inference-for-response-adaptive-randomization-procedures-with-adjusted-optimal-allocation-proportions
#19
Hongjian Zhu
Seamless phase II/III clinical trials have attracted increasing attention recently. They mainly use Bayesian response adaptive randomization (RAR) designs. There has been little research into seamless clinical trials using frequentist RAR designs because of the difficulty in performing valid statistical inference following this procedure. The well-designed frequentist RAR designs can target theoretically optimal allocation proportions, and they have explicit asymptotic results. In this paper, we study the asymptotic properties of frequentist RAR designs with adjusted target allocation proportions, and investigate statistical inference for this procedure...
December 12, 2016: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/27937059/statistical-evaluation-of-the-scaled-criterion-for-drug-interchangeability
#20
Jianghao Li, Shein-Chung Chow
As more and more generic drug products become available in the marketplace, it is a concern whether these generic drug products can be used interchangeably in terms of their quality, safety, and efficacy. The United States Food and Drug Administration (FDA) indicates that an approved generic drug product can serve as a substitute for the innovative drug product. The FDA, however, does not indicate that approved generic drug products can be used interchangeably even if they are bioequivalent to the same innovative drug product...
December 12, 2016: Journal of Biopharmaceutical Statistics
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