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Model-based phase I designs incorporating toxicity and efficacy for single and dual agent drug combinations: methods
Sumithra J Mandrekar1, Rui Qin, Daniel J Sargent
1Department of Health Sciences Research, Mayo Clinic, Rochester, MN 55905, USA. mandrekar.sumithra@mayo.edu
Abstract:
Novel therapies are challenging the standards of drug development. Agents with specific biologic targets, unknown dose-efficacy curves, and limited toxicity mandate novel designs to identify biologically optimal doses. We review two model-based designs that utilize either a proportional odds model or a continuation ratio model to identify an optimal dose of a single or two-agent combination in a Phase I setting utilizing both toxicity and efficacy data. A continual reassessment method with straightforward dose selection criterion using accumulated data from all patients treated until that time point is employed while allowing for separate toxicity and efficacy curves for each drug in a two-drug setting. The simulation studies demonstrate considerable promise, at least theoretically, in the ability of such model-based designs to identify the optimal dose. Despite such favorable operating characteristics, there are several pragmatic challenges that hinder the routine implementation of such model-based designs in practice. We review and offer practical solutions to potentially overcome some of these challenges. The acceptance and integration of these designs in practice may be quicker and easier if they are developed in concert with a clinical paradigm.
Insights
Novel therapies require advanced drug development designs. Model-based approaches using toxicity and efficacy data help identify optimal doses for new agents, though practical challenges remain.
Area of Science:
- Clinical pharmacology
- Biostatistics
- Drug development
Background:
- Novel therapeutic agents present unique challenges in drug development due to specific targets, unknown dose-efficacy relationships, and limited toxicity data.
- Traditional dose-finding methods may be insufficient for these novel agents, necessitating advanced statistical designs.
- Phase I clinical trials are critical for establishing safe and effective doses.
Purpose of the Study:
- To review model-based designs for identifying optimal doses of single or combination agents in Phase I trials.
- To explore the use of proportional odds and continuation ratio models for dose optimization.
- To address practical challenges in implementing these advanced designs in clinical practice.
Main Methods:
- Review of two model-based designs: proportional odds and continuation ratio models.
- Utilizing a continual reassessment method (CRM) with accumulated patient data for dose selection.
- Incorporating separate toxicity and efficacy curves for each drug in two-agent combination studies.
Main Results:
- Simulation studies indicate theoretical promise for model-based designs in identifying optimal doses.
- The proposed methods allow for flexible modeling of toxicity and efficacy for individual agents.
- Practical challenges to implementation were identified and potential solutions discussed.
Conclusions:
- Model-based designs offer a promising approach to optimize dosing for novel therapies in early-phase trials.
- Addressing implementation challenges is crucial for the routine adoption of these advanced statistical methods.
- Closer alignment between design development and clinical paradigms can facilitate quicker integration.
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