Redefining Regulatory Proof: The End of the Two-Trial Paradigm

Area of Science:

• Regulatory Science
• Biostatistics
• Health Technology Assessment

Background:

• The Food and Drug Administration (FDA) has shifted to a single pivotal trial as the default standard for drug approval.
• This represents a move from replication-based validation to a coherence-based model of evidence sufficiency.
• This regulatory shift has global implications for drug development strategies.

Purpose of the Study:

• To analyze the methodological and epistemological concerns arising from the FDA's new single pivotal trial standard.
• To evaluate the impact of this shift on the statistical rationale and risk assessment in drug approval.
• To examine the potential consequences for regulatory flexibility and health technology assessment.

Main Methods:

• Analysis of the FDA's revised evidentiary standards for drug approval.
• Critique of the statistical rationale, considering factors like prior plausibility and statistical power.
• Examination of the role of replication versus post-marketing evidence in ensuring robustness and external validity.

Main Results:

• The new standard may not fully incorporate contextual factors influencing false-positive risk.
• Prior plausibility is handled informally, and post-marketing data may not fully compensate for lack of independent replication.
• Replication serves as a crucial safeguard for robustness and external validity, beyond mere statistical redundancy.

Conclusions:

• The shift to a single pivotal trial standard raises significant methodological and epistemological concerns.
• Increased regulatory flexibility without explicit safeguards may lead to heterogeneous evidentiary thresholds.
• The discriminative function of health technology assessment may be weakened by this reform, potentially impacting evidence quality and patient safety.