Robust Emax Model Fitting: Addressing Nonignorable Missing Binary Outcome in Dose-Response Analysis

Fuente: arXiv
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Autores principales: Zhang, Jiangshan, Pradhan, Vivek, Zhao, Yuxi
Formato: Preprint
Publicado: 2024
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author Zhang, Jiangshan
Pradhan, Vivek
Zhao, Yuxi
author_facet Zhang, Jiangshan
Pradhan, Vivek
Zhao, Yuxi
contents The Binary Emax model is widely employed in dose-response analysis during drug development, where missing data often pose significant challenges. Addressing nonignorable missing binary responses, where the likelihood of missing data is related to unobserved outcomes, is particularly important, yet existing methods often lead to biased estimates. This issue is compounded when using the regulatory-recommended imputing as treatment failure approach, known as non-responder imputation. Moreover, the problem of separation, where a predictor perfectly distinguishes between outcome classes, can further complicate likelihood maximization. In this paper, we introduce a penalized likelihood-based method that integrates a modified Expectation-Maximization algorithm in the spirit of Ibrahim and Lipsitz to effectively manage both nonignorable missing data and separation issues. Our approach applies a noninformative Jeffreys prior to the likelihood, reducing bias in parameter estimation. Simulation studies demonstrate that our method outperforms existing methods, such as NRI, and the superiority is further supported by its application to data from a Phase II clinical trial. Additionally, we have developed an R package, ememax, to facilitate the implementation of the proposed method.
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id arxiv_https___arxiv_org_abs_2410_00259
institution arXiv
publishDate 2024
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spellingShingle Robust Emax Model Fitting: Addressing Nonignorable Missing Binary Outcome in Dose-Response Analysis
Zhang, Jiangshan
Pradhan, Vivek
Zhao, Yuxi
Methodology
Applications
The Binary Emax model is widely employed in dose-response analysis during drug development, where missing data often pose significant challenges. Addressing nonignorable missing binary responses, where the likelihood of missing data is related to unobserved outcomes, is particularly important, yet existing methods often lead to biased estimates. This issue is compounded when using the regulatory-recommended imputing as treatment failure approach, known as non-responder imputation. Moreover, the problem of separation, where a predictor perfectly distinguishes between outcome classes, can further complicate likelihood maximization. In this paper, we introduce a penalized likelihood-based method that integrates a modified Expectation-Maximization algorithm in the spirit of Ibrahim and Lipsitz to effectively manage both nonignorable missing data and separation issues. Our approach applies a noninformative Jeffreys prior to the likelihood, reducing bias in parameter estimation. Simulation studies demonstrate that our method outperforms existing methods, such as NRI, and the superiority is further supported by its application to data from a Phase II clinical trial. Additionally, we have developed an R package, ememax, to facilitate the implementation of the proposed method.
title Robust Emax Model Fitting: Addressing Nonignorable Missing Binary Outcome in Dose-Response Analysis
topic Methodology
Applications
url https://arxiv.org/abs/2410.00259