15 papers
BOP2-ENR: a Bayesian optimal phase II design for adaptive enrichment with family-wise error rate control and a bound on joint-claim power
Kentaro Takeda, Belay B. Yimer, Masahiro Kojima
The Bayesian optimal phase II (BOP2) design accommodates simple and complex endpoints but does not address biomarker-guided enrichment or multiplicity control across pooled and sub…
Feedback-Aware Tuning of Recursive Q-Learning
Masahiro Kojima
Model choice in backward Q-learning is recursive because a later-stage choice changes the response supplied to an earlier regression and can alter its model-comparison statistic. S…
Finite-Boundary Reduction and Exact Verification of Strong Familywise Error in Active-Count-Coupled Multi-Arm Efficacy-Toxicity Monitoring
Masahiro Kojima, Hisato Sunami, Kentaro Takeda
Randomized dose-optimization trials may screen several candidate doses using binary efficacy and toxicity outcomes. A dose is inadmissible if efficacy is insufficient or toxicity i…
A staggered seamless dose-optimization design for co-developing monotherapy and combination therapy
Masahiro Kojima, Kentaro Takeda, Ying Yuan
Contemporary oncology drug development increasingly requires efficient dose-optimization strategies that evaluate monotherapy (Mono) and combination therapy (Combo) while balancing…
A seamless dose-optimization design for monotherapy and combination therapy
Kentaro Takeda, Masahiro Kojima
The emergence of molecular-targeted agents and immune-oncology therapies has fundamentally transformed oncology drug development, necessitating evolution beyond traditional dose-fi…
A Globally Calibrated Bayesian Optimal Phase II Design for Adaptive Enrichment Trials
Masahiro Kojima, Hisato Sunami, Masaaki Kuriki
Adaptive enrichment allows development of an experimental treatment to continue when its activity is insufficient in an all-comer population but remains promising in a prespecified…
Fast Power Evaluation under Biased-Coin Minimization: Sampling and Randomization Calibration
Masahiro Kojima
Design-stage power and sample-size evaluation under biased-coin minimization can be computationally intensive when a prespecified randomization test is reproduced within every simu…
Outcome-blinded sample size re-estimation for externally controlled single-arm trials using baseline covariates
Keisuke Hanada, Masahiro Kojima
Externally controlled single-arm trials provide an option when limited patient populations or ethical constraints make concurrent randomized controls impractical, including in rare…
Hybrid Non-informative and Informative Prior Model-assisted Designs for Mid-trial Dose Insertion
Kana Yamada, Hisato Sunami, Kentaro Takeda +2
In oncology phase I trials, model-assisted designs have been increasingly adopted because they enable adaptive yet operationally simple dose adjustment based on accumulating safety…
A Clustering Approach for Basket Trials Based on Treatment Response Trajectories
Masahiro Kojima, Keisuke Hanada, Atsuya Sato
Heterogeneity in efficacy is sometimes observed across baskets in basket trials. In this study, we propose a model-free clustering framework that groups baskets based on transition…
Sample size re-estimation in blinded hybrid-control design using inverse probability weighting
Masahiro Kojima, Shunichiro Orihara, Keisuke Hanada +1
With the increasing availability of data from historical studies and real-world data sources, hybrid control designs that incorporate external data into the evaluation of current s…
Integrate Meta-analysis into Specific Study (InMASS) for Estimating Conditional Average Treatment Effect
Keisuke Hanada, Masahiro Kojima
Randomized controlled trials are the standard method for estimating causal effects, ensuring sufficient statistical power and confidence through adequate sample sizes. However, ach…
Bayesian Parametric Methods for Deriving Distribution of Restricted Mean Survival Time
Keisuke Hanada, Masahiro Kojima
We propose a Bayesian method for deriving the distribution of restricted mean survival time (RMST) using posterior samples, which accounts for covariates and heterogeneity among cl…
Random Effect Restricted Mean Survival Time Model
Keisuke Hanada, Masahiro Kojima
The restricted mean survival time (RMST) model has been garnering attention as a way to provide a clinically intuitive measure: the mean survival time. RMST models, which use metho…
Adjusting confidence intervals under covariate-adaptive randomization in non-inferiority and equivalence trials
Masahiro Kojima, Hirotaka Mano, Kana Yamada +3
Regulatory authorities guide the use of permutation tests or randomization tests so as not to increase the type-I error rate when applying covariate-adaptive randomization in rando…