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Journal of Biopharmaceutical Statistics

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https://www.readbyqxmd.com/read/28060570/adjustment-for-unbalanced-sample-size-for-analytical-biosimilar-equivalence-assessment
#1
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 product 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
#2
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
#3
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
#4
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 has been proposed and received much attention for assessing drug interchangeability between T and R, where R could be either an 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
#5
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
#6
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
#7
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
#8
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
#9
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
#10
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
#11
Syed Shahadat Hossain, Nabil Awan
Clinical trials designed for survival probability estimation of different treatment policies for chronic diseases like Cancer, Leukemia, 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
#12
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. Well-designed frequentist RAR 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 we 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
#13
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. FDA, however, does not indicate that approved generic drug products can be used interchangeably even they are bioequivalent to the same innovative drug product...
December 12, 2016: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/27936356/bayesian-quantile-regression-for-nonlinear-mixed-effects-joint-models-for-longitudinal-data-in-presence-of-mismeasured-covariate-errors
#14
Yangxin Huang, Jiaqing Chen, Huahai Qiu
Quantile regression (QR) models have recently received increasing attention in longitudinal studies where measurements of the same individuals are taken repeatedly over time. When continuous (longitudinal) responses follow a distribution that is quite different from a normal distribution, usual mean regression (MR)-based linear models may fail to produce efficient estimators whereas QR-based linear models may perform satisfactorily (Geraci and Bottai, 2007; Koenker, 2004; Liu and Bottai, 2009). To the best of our knowledge, there have been very few studies on QR-based nonlinear models for longitudinal data in comparison of MR-based nonlinear models...
December 9, 2016: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/27936355/sample-size-determination-for-a-three-arm-equivalence-trial-of-poisson-and-negative-binomial-responses
#15
Yu-Wei Chang, Yi Tsong, Zhigen Zhao
Assessing equivalence or similarity has drawn much attention recently as many drug products have lost or will lose their patents in the next few years, especially certain best-selling biologics. To claim equivalence between the test treatment and the reference treatment when assay sensitivity is well-established from historical data, one has to demonstrate both superiority of the test treatment over placebo and equivalence between the test treatment and the reference treatment. Thus, there is urgency for practitioners to derive a practical way to calculate sample size for a three-arm equivalence trial...
December 9, 2016: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/27936354/comparison-of-tests-of-contingency-tables
#16
Saeid Amiri, Reza Modarres
We explore the use of bootstrap for testing independence of two categorical variables. We develop a theoretical justification for bootstrapping a contingency table and provide more accurate inference for small sample sizes. We also study the effect of equalized marginals on tests of independence. The small sample properties of the proposed and existing tests of independence are examined using Monte Carlo simulations. It is shown that the Fisher exact test and the Chi-squared test with continuity correction are very conservative and can not be recommended to test independence with small sample sizes...
December 9, 2016: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/27936352/prescott-tests-of-equality-in-binary-data-under-a-three-treatment-three-perod-crossover-design
#17
Lixia Zhu, Kung-Jong Lui
Three test procedures accounting for patients with tied responses based on Prescott's ideas are developed for comparing three treatments under a three-period crossover trial in binary data. Monte Carlo simulation is employed to evaluate the performance of these test procedures in a variety of situations. The test procedures proposed here are noted to have power larger than those procedures, which utilize only those patients with un-tied responses. The data taken from a three-period crossover trial comparing two different doses of an analgesic with placebo for the relief of primary dysmenorrhea are used to illustrate the use of the test procedures developed here...
December 9, 2016: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/27936343/assessing-bioequivalence-and-drug-interchangeability
#18
Meng Chen, Shein-Chung Chow
As indicated by the US Food and Drug Administration (FDA), approved generic drug products can be used as substitutes for their respective innovative drug products. The FDA, however, does not indicate that two generic copies of the same innovative drug can be used interchangeably, even though they have been shown to be bioequivalent to the same innovative drug product. As more and more generic drug products become available in the market place, it is a concern whether these approved generic drug products have the same quality and safety/efficacy and hence can be used interchangeably...
December 9, 2016: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/27935446/sample-size-requirement-in-analytical-studies-for-similarity-assessment
#19
Shein-Chung Chow, Fuyu Song, He Bai
For assessment of biosimilar products, FDA recommends a stepwise approach for obtaining the totality-of-the-evidence for assessing biosimilarity between a proposed biosimilar product and its corresponding innovative biologic product (FDA, 2015). The stepwise approach starts with analytical studies for assessing similarity in critical quality attributes (CQAs) which are relevant to clinical outcomes at various stages of manufacturing process (Christl, 2015). For CQAs that are most relevant to clinical outcomes, FDA requires equivalence test be performed for similarity assessment based on an equivalence acceptance criterion that is obtained using single test value of some selected reference lots (Tsong, 2015)...
December 9, 2016: Journal of Biopharmaceutical Statistics
https://www.readbyqxmd.com/read/27922340/ratio-of-means-vs-difference-of-means-as-measures-of-superiority-noninferiority-and-average-bioequivalence
#20
Wanjie Sun, Stella Grosser, Yi Tsong
Ratio of means (ROM) and difference of means (DOM) are often used in a superiority, noninferiority (NI), or average bioequivalence (ABE) test to evaluate whether the test mean is superior, NI, or equivalent to the reference (placebo or active control) mean. The literature provides recommendations regarding how to choose between ROM and DOM, mainly for superiority testing. In this article, we evaluated these two measures from other perspectives and cautioned the potential impact of different scoring systems/transformation for the same outcome (which is not rarely seen in practice) on the power of a ROM or DOM test for superiority, NI, or ABE...
December 6, 2016: Journal of Biopharmaceutical Statistics
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