{"title":"Bayesian meta-analysis for rare outcomes.","authors":"Ohud Alqasem, Haydar Demirhan, Anil Dolgun","doi":"10.1080/10543406.2025.2512205","DOIUrl":"10.1080/10543406.2025.2512205","url":null,"abstract":"<p><p>Binary meta-analysis studies with rare outcomes frequently include zero or a small number of observations in study groups, creating a sparsity issue with the data. The corrections applied to eliminate the impact of the zero cell counts introduce a bias to the meta-analysis results and potentially distort the inferences about the treatment effect and heterogeneity among the studies. The boundaries of interval estimates become highly biased due to the sparsity of the data. This study proposes two Bayesian random-effects meta-analysis models based on the beta-binomial model with an arc-sine-square-root transformation. The performance of the models in estimating the treatment effect and the in-between study variance is assessed with an extensive Monte Carlo simulation study, and a frequently referred meta-analysis dataset is revisited. The models provide accurate estimates of treatment effect and heterogeneity parameters without a continuity correction. They provide well-calibrated, narrow interval estimates with sufficient coverage of true treatment effect and in-between study variance. They are robust against zero cell counts, very low event probabilities, and unbalanced, skewed data distributions. Recommendations are given for the practical use of the proposed models, and the required model scripts are provided to implement the models using R software.</p>","PeriodicalId":54870,"journal":{"name":"Journal of Biopharmaceutical Statistics","volume":" ","pages":"1313-1335"},"PeriodicalIF":1.3,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144250951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Joint linear and nonlinear mixed effects model with random change points for left-censored longitudinal data: application to HIV surveillance.","authors":"Binod Manandhar, Hongbin Zhang","doi":"10.1080/10543406.2025.2547592","DOIUrl":"10.1080/10543406.2025.2547592","url":null,"abstract":"<p><p>A change-point model is useful for longitudinal data to infer the time to an event that induces a change of trajectory within the study period. We present a random change-point model that fits the linear and non-linear mixed effects for pre- and post-change-points, respectively. We address the left-censored observations in the model. The stochastic approximation expectation maximization (SAEM) with the Metropolis Hastings sampler is used to fit the random change-point non-linear mixed effects model. We apply our method to the viral load (VL) longitudinal data reported to the HIV surveillance registry in New York City. We evaluate the model with a data simulation.</p>","PeriodicalId":54870,"journal":{"name":"Journal of Biopharmaceutical Statistics","volume":"36 6","pages":"1511-1521"},"PeriodicalIF":1.3,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149277104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Weighted sum and order statistics methods for dynamic information borrowing in basket trials.","authors":"Cheng Huang, Chenghao Chu, Yimeng Lu, Bingming Yi, Ming-Hui Chen","doi":"10.1080/10543406.2025.2537088","DOIUrl":"10.1080/10543406.2025.2537088","url":null,"abstract":"<p><p>In basket trials, the same investigational therapy is studied on multiple sub-populations simultaneously under a single protocol. The goal of basket trials is to identify the sub-populations in which the therapy is effective. Basket trials have become a popular and generally accepted study design in disease areas including but not limited to oncology and rare diseases, for their advantages in operation and ethical considerations. Extensive research work on information borrowing has been conducted to explore the statistical efficiency in basket trials. In this paper, two novel frequentist methods for basket trials are proposed. The first method borrows information to minimize the mean squared errors in the treatment effect estimation. The second method uses information across all baskets to optimize the multiple testing task in detecting the treatment effects in each basket. Extensive simulation studies show that the proposed methods substantially improved statistical efficiency in basket trials while limiting family-wise error rate inflation. Both methods can be implemented with common statistical models with or without adjustment for covariates.</p>","PeriodicalId":54870,"journal":{"name":"Journal of Biopharmaceutical Statistics","volume":" ","pages":"1420-1439"},"PeriodicalIF":1.3,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144762352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Interval estimation for three-class Youden index with verification bias.","authors":"Shuangfei Shi, Shirui Wang, Gengsheng Qin","doi":"10.1080/10543406.2025.2549361","DOIUrl":"10.1080/10543406.2025.2549361","url":null,"abstract":"<p><p>Youden index is one of the broadly used measurements to assess the accuracy of the diagnostic test under consideration. In real medical diagnostic studies, verification of the true disease status might only be partially available due to ethical and cost considerations, and the drawbacks of gold-standard tests. Therefore, statistical evaluation of the diagnostic accuracy of a test based only on data from subjects with verified disease status is typically biased. Youden indices for the assessment of accuracy and optimal cutoff point(s) selection in diagnostic tests classifying two disease stages and three disease stages have been proposed without considering this verification bias. In this article, we develop novel confidence intervals for three-class Youden index to correct verification bias under the assumption that the true disease status, if missing, is missing at random (MAR). The proposed methods provide a comprehensive guide to dealing with the verification bias in diagnostic test accuracy studies and lead to a better choice of diagnostic tests.</p>","PeriodicalId":54870,"journal":{"name":"Journal of Biopharmaceutical Statistics","volume":" ","pages":"1522-1543"},"PeriodicalIF":1.3,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144979540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"BPED: A Bayesian basket design for pediatric trials with external data.","authors":"Yimei Li, Ying Yuan","doi":"10.1080/10543406.2025.2512203","DOIUrl":"10.1080/10543406.2025.2512203","url":null,"abstract":"<p><p>The basket trial is a novel type of trial that evaluates one treatment in multiple indications (such as cancer types) simultaneously. One challenge of applying the basket trial design to pediatric studies is limited accrual, resulting in low statistical power. To address this issue, we propose a Bayesian <u>b</u>asket design for <u>p</u>ediatric trials with <u>e</u>xternal <u>d</u>ata (BPED) that performs dual-information borrowing to improve the design efficiency: borrow information from the external data to the pediatric trial, and borrow information between the cancer types within the pediatric trial. BPED also accommodates potential heterogeneous treatment effects across cancer types by allowing each cancer type belonging to the sensitive or insensitive latent subgroups. The design adaptively updates the members of the subgroups based on the accumulated pediatric and external data to make go/no-go decisions for each cancer type. The simulation study shows that, compared to some existing designs, BPED yields higher power to detect the treatment effect for sensitive cancer types and maintains a desirable type I error rate for insensitive cancer types.</p>","PeriodicalId":54870,"journal":{"name":"Journal of Biopharmaceutical Statistics","volume":" ","pages":"1293-1312"},"PeriodicalIF":1.3,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12354168/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144217621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Sample size determination for a study with variable follow-up time.","authors":"Guogen Shan, Yahui Zhang, Xinlin Lu, Yulin Li, Minggen Lu, Zhigang Li","doi":"10.1080/10543406.2025.2469879","DOIUrl":"10.1080/10543406.2025.2469879","url":null,"abstract":"<p><p>For a study to detect the outcome change at the follow-up visit from baseline, the pre-test and post-test design is commonly used to assess the treatment-control difference. Several existing methods were developed for sample size calculation including the subtraction method, analysis of covariance (ANCOVA), and linear mixed model. The first two methods can be used when the follow-up time is the same as scheduled. Although the linear mixed model can analyze the repeated measures by including the actual visit time to account for the variability of the follow-up time, it often assumes a constant treatment-control difference at any follow-up time which may not be correct in practice. We propose to develop a new statistical model to compare the treatment-control difference at the planned follow-up time while controlling for the follow-up time variation. The spline functions are used to estimate the trajectories of the treatment arm and the control arm. We compared the performance of these methods with regards to type I error rate, statistical power, and sample size under various conditions. These four methods all control for the type I error rate. The new method and the ANCOVA method are often more powerful than the other two methods, and they have similar statistical power when a linear disease progression is satisfied. For a study with non-linear disease progression, the new method can be more powerful than the ANCOVA method. We used data from a completed Alzheimer's disease trial to illustrate the application of the proposed method.</p>","PeriodicalId":54870,"journal":{"name":"Journal of Biopharmaceutical Statistics","volume":" ","pages":"1211-1226"},"PeriodicalIF":1.3,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12353296/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143517579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abd El-Raheem M Abd El-Raheem, Ibrahim A A Shanan, Mona Hosny
{"title":"Saddlepoint p-values for the class of bivariate two-sample tests under generalized randomized block design.","authors":"Abd El-Raheem M Abd El-Raheem, Ibrahim A A Shanan, Mona Hosny","doi":"10.1080/10543406.2025.2592617","DOIUrl":"10.1080/10543406.2025.2592617","url":null,"abstract":"<p><p>Bivariate data arise in several research fields, such as clinical trials and reliability studies. In clinical trials, patients are distributed into treatment groups using randomization designs, which prevent selection bias and incidental bias. Generalized randomized block design is among clinical trials' most famous and widely used randomization designs. This article investigates the use of the saddlepoint method to approximate the underlying permutation distributions of bivariate two-sample tests under a generalized randomized block design. Additionally, the saddlepoint method is utilized to approximate the tail probability of these tests. Through comprehensive simulation studies, the accuracy of this approximation method is thoroughly evaluated, revealing a significant improvement in precision compared to the asymptotic normal approximation.</p>","PeriodicalId":54870,"journal":{"name":"Journal of Biopharmaceutical Statistics","volume":" ","pages":"1687-1698"},"PeriodicalIF":1.3,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145679535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Blinded sample size re-estimation in a crossover study.","authors":"Shaofei Zhao, Balakrishna Hosmane, Chen Chen, Yi-Lin Chiu","doi":"10.1080/10543406.2025.2575947","DOIUrl":"10.1080/10543406.2025.2575947","url":null,"abstract":"<p><p>Bioequivalence studies play a pivotal role in drug development by establishing the clinical equivalence of two drug formulations. These studies often utilize crossover designs to facilitate within-subject treatment comparisons, optimizing statistical power with fewer subjects. However, uncertainty regarding the variance of a new drug or formulation during planning presents a challenge for sample size determination. While adaptive designs offer a potential solution, their application in crossover studies is less explored compared to group sequential designs, and many existing adaptive methods require data unblinding during the trial. Only two blinded sample size re-estimation approaches have been developed in crossover settings to date. In this paper, we propose a novel method for blinded within-subject variance estimation at interim analysis and re-estimate the sample size to achieve the desired power. We thoroughly investigate its analytical properties and introduce a refined, unbiased estimator. Through extensive simulation studies, our method shows comparable performance to existing blinded approaches and offers a distinct advantage in scenarios with small treatment differences and large subject variances.</p>","PeriodicalId":54870,"journal":{"name":"Journal of Biopharmaceutical Statistics","volume":" ","pages":"1615-1633"},"PeriodicalIF":1.3,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145551806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
İlker Ünal, Esin Ünal, Yaşar Sertdemir, Murat Kobaner
{"title":"Defining optimal cut-off points for multiple class ROC analysis: generalization of the Index of Union method.","authors":"İlker Ünal, Esin Ünal, Yaşar Sertdemir, Murat Kobaner","doi":"10.1080/10543406.2025.2528639","DOIUrl":"10.1080/10543406.2025.2528639","url":null,"abstract":"<p><p>A variety of well-developed methodologies exist for the purpose of binary classification. Some of these methodologies have been extended to accommodate multi-class settings with three or even more classes. In this study, we generalize the Index of Union (IU) method, which we previously demonstrated to be more effective than other methods in binary classification. We evaluate the Generalized Index of Union (GIU) method and compare it with existing methods using both simulated and real data. The results of the comparisons demonstrated that the GIU method is an effective approach in a multitude of scenarios, including those involving high volume under the surface (VUS) values and all distributions. It is therefore recommended that the GIU method can be used to determine the optimal cut-off points in all the ROC analyses due to its structure, which does not require complex calculations and thus provides fast results.</p>","PeriodicalId":54870,"journal":{"name":"Journal of Biopharmaceutical Statistics","volume":" ","pages":"1401-1419"},"PeriodicalIF":1.3,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144602282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Multi-armed bandits backfill Bayesian optimal interval design.","authors":"Masahiro Kojima, Kentaro Takeda","doi":"10.1080/10543406.2025.2602463","DOIUrl":"10.1080/10543406.2025.2602463","url":null,"abstract":"<p><p>In cancer phase I dose-finding clinical trials, following the Project Optimus of the U.S. Food and Drug Administration, there is an increasing need to add backfill cohorts not only to determine the maximum tolerated dose but also to identify the optimal effective dose for subsequent Phase II trials. In this study, multi-armed bandit algorithms, known for their superiority in exploratory selection, are applied to the problem of selecting which dose levels to add backfill cohorts. Additionally, we propose a method that incorporates efficacy modeling into the multi-armed bandit algorithm. The multi-armed bandit approach is straightforward, requiring only simple calculations, making it highly accessible. To enhance understanding of backfill cohort addition using multi-armed bandit algorithms, we provide demonstrations and evaluate the performance through simulations.</p>","PeriodicalId":54870,"journal":{"name":"Journal of Biopharmaceutical Statistics","volume":" ","pages":"1699-1712"},"PeriodicalIF":1.3,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145806336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}