Related Experiment Video
Updated: Jun 25, 2026
15:04
Potentiation of Anticancer Antibody Efficacy by Antineoplastic Drugs: Detection of Antibody-drug Synergism Using the Combination Index Equation
Published on: January 19, 2019
Treatment-subgroup interaction: an example from a published, phase II clinical trial
Carolyn E Behrendt1, Edmund A Gehan
1Department of Biostatistics, City of Hope National Medical Center and Beckman Research Institute, Duarte, CA, USA. cbehrendt@coh.org
Contemporary Clinical Trials
|February 24, 2009
Summary
Phase II trials must account for patient subgroups to avoid errors. Ignoring interactions between treatment and patient subgroups can lead to inaccurate results, as seen in a leukemia trial reanalysis.
Area of Science:
- Oncology
- Clinical Trial Design
- Biostatistics
Background:
- Phase II trials often overlook patient heterogeneity and treatment-subgroup interactions.
- This oversight can lead to significant false positive and false negative error rates.
- Previous work highlighted this issue using simulations.
Purpose of the Study:
- To reanalyze a published Phase II trial.
- To emphasize the importance of considering patient heterogeneity and treatment-subgroup interactions in Phase II study design and analysis.
- To demonstrate the impact of these factors in a real-world clinical scenario.
Main Methods:
- Reanalysis of a published single-arm Phase II trial evaluating amsacrine plus OAP (OAP: amsacrine, cytosine arabinoside, vincristine, and prednisone) for adult acute leukemia.
- Utilized analysis of covariance (ANCOVA) with historical control data.
- Classified patients into favorable or unfavorable prognostic subgroups based on predicted response to standard treatment.
Main Results:
- When prognostic subgroups were ignored, experimental (OAP) and standard treatments showed similar response rates.
- ANCOVA revealed statistically significant effects of subgroup, treatment, and their interaction.
- Experimental treatment was superior in unfavorable prognosis subgroups but inferior in favorable prognosis subgroups compared to standard treatment.
Conclusions:
- Real-world data confirms that treatment efficacy can vary significantly across patient subgroups.
- Phase II trial designs must incorporate methods to address between-patient heterogeneity and potential treatment-subgroup interactions.
- Failure to do so can mask true treatment effects or suggest false efficacy.
Related Concept Videos
01:16Clinical Trials
Clinical trials are prospective experimental studies conducted on humans to determine the safety and efficacy of treatments, drugs, diet methods, and medical devices. Using statistics in clinical trials enables researchers to derive reasonable and accurate conclusions from the collected data, allowing them to make wise decisions in uncertain situations. In medical research, statistical methods are crucial for preventing errors and bias.
There are four phases in a clinical trial. A phase one...
There are four phases in a clinical trial. A phase one...
01:11Clinical Trials: Overview
Clinical development focuses on how the drug will interact with the human body and encompasses four key phases of clinical trials, each serving a specific purpose in assessing the safety and effectiveness of new drugs. These phases overlap and build upon one another. Phase I involves a small group of healthy volunteers (typically 20-80 individuals) or, in cases where significant toxicity is expected, patients with the targeted disease, such as cancer or AIDS. The volunteers are tested for...
01:15Bioavailability Study Design: Healthy Subjects Versus Patients
Bioavailability studies are essential for evaluating a drug's therapeutic efficacy and understanding its absorption patterns under various physiological conditions. Conducting such studies on target patient populations provides more relevant data by simulating real-world disease states. However, practical challenges often necessitate the use of young, healthy adult volunteers as study subjects.Patients may exhibit altered drug absorption patterns due to the effects of the disease itself,...
01:11Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase
Genetic polymorphisms in drug targets have emerged as critical determinants of interindividual variability in drug response and toxicity. Pharmacogenomic investigations increasingly focus on identifying these variations to personalize and optimize therapeutic interventions. A drug target may be a receptor, enzyme, or signaling protein involved in pharmacologic responses or disease-related pathways. While early pharmacogenetic studies focused primarily on drug metabolism, current research...
01:29Therapeutic Drug Monitoring: Affecting Factors
Therapeutic Drug Monitoring (TDM) is the clinical practice of measuring specific drug levels in a patient's blood or body tissues to manage and optimize therapy. TDM is crucial for drugs with narrow therapeutic windows, like warfarin and phenytoin, where incorrect doses can lead to treatment failure or severe side effects. This monitoring ensures the dosage administered is within a safe and effective range. The factors affecting therapeutic drug monitoring include:Patient-Specific Factors:a.
01:26Drug Administration and Therapy Phases: Overview
Drugs, the chemical agents used in diagnosing, treating, or preventing diseases, undergo a four-phase process of development: pharmaceutic, pharmacokinetics, pharmacodynamics, and therapeutic.
The pharmaceutical phase focuses on leveraging the physicochemical properties of the drug to design and manufacture an effective product. Variants include orally administered tablets or capsules, topical creams or ointments, and parenteral-delivery solutions or emulsions.
The pharmacokinetic phase...
The pharmaceutical phase focuses on leveraging the physicochemical properties of the drug to design and manufacture an effective product. Variants include orally administered tablets or capsules, topical creams or ointments, and parenteral-delivery solutions or emulsions.
The pharmacokinetic phase...