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Influence of unrecognized molecular heterogeneity on randomized clinical trials
Rebecca A Betensky1, David N Louis, J Gregory Cairncross
1Department of Biostatistics, Harvard School of Public Health, 655 Huntington Avenue, Boston, MA 02115, USA. betensky@hsps.harvard.edu
Purpose:
In solid tumor oncology, decisions regarding treatment and eligibility for trials are governed by histologic diagnosis. Despite this reliance on histology and the assumption that histology defines the disease, underlying molecular heterogeneity likely differentiates among patients' outcomes.
Patients And Methods:
To illustrate how unrecognized molecular heterogeneity might obscure a truly effective new therapy for cancer, we analyzed the planning assumptions and results of a hypothetical randomized controlled trial of chemoradiotherapy for a cancer found to be drug sensitive in preliminary phase II studies.
Results:
Randomized controlled trials of effective cancer therapies can be falsely negative if therapeutic benefit is overestimated during study design because of enrichment of phase II trials for treatment-sensitive subtypes, a beneficial effect in responding patients is diluted by large numbers of nonresponding patients, or a beneficial effect in responders is reversed by a negative effect in nonresponders.
Conclusion:
Molecular heterogeneity, if it confers different risks to patients and is unaccounted for in the design of a randomized study, can result in a clinical trial that is underpowered and fails to detect a truly effective new therapy for cancer.
Insights
Molecular heterogeneity in solid tumors can mask effective cancer therapies. Unaccounted variations can lead to underpowered clinical trials that fail to identify truly beneficial treatments.
Area of Science:
- Oncology
- Translational Research
- Clinical Trial Design
Background:
- Histologic diagnosis traditionally guides cancer treatment and trial eligibility.
- Underlying molecular heterogeneity may significantly impact patient outcomes, despite a uniform histology.
- Current reliance on histology may overlook critical disease variations.
Purpose of the Study:
- To illustrate how unrecognized molecular heterogeneity can obscure effective cancer therapies.
- To analyze the impact of heterogeneity on randomized controlled trial (RCT) design and interpretation.
- To demonstrate potential pitfalls in evaluating novel cancer treatments.
Main Methods:
- Analysis of planning assumptions and results of a hypothetical RCT.
- Simulation of chemoradiotherapy for a hypothetical drug-sensitive cancer.
- Evaluation of scenarios where heterogeneity affects trial outcomes.
Main Results:
- RCTs for effective cancer therapies can yield false-negative results.
- Overestimation of therapeutic benefit during design, due to Phase II enrichment, can dilute true effects.
- Beneficial effects in responders may be reversed by negative effects in nonresponders.
Conclusions:
- Molecular heterogeneity, if unaddressed in RCT design, can lead to underpowered studies.
- Failure to account for patient-specific risks due to heterogeneity can prevent the detection of effective therapies.
- Rethinking trial design to incorporate molecular profiling is crucial for accurate cancer treatment evaluation.