ideasIdea
Drug labels must state which biomarker assays were validated and how they compare
A drug label says 'for PD-L1 positive patients' but does not say that other tests give different answers. Labels should list the validated tests and how much they disagree.
Labels reference the companion diagnostic used in the pivotal trial but not the performance of other assays commonly used in practice, leaving clinicians to guess whether their laboratory's test is equivalent. Requiring a structured concordance section (validated assays, concordance data with other widely used assays, known discordant regions) would surface the uncertainty and drive sponsors to generate bridging data.
Hypothesis
Labels with concordance sections will be followed by an increase in published bridging studies and a reduction in the use of unvalidated assay substitutions, measurable in laboratory surveys.
Rationale
Clinicians substitute assays in practice for cost and availability reasons; the risk of that substitution is currently invisible in the primary document they consult.
What would test it
Draft the section for five biomarker-restricted labels using existing concordance literature; survey clinicians and laboratories on utility; propose as a labelling requirement.
Maturity
speculative
Who has to act
regulator
Cost to try
Small (under $1M)
Years to first evidence
2
Bottlenecks it attacks
- Biomarkers are not validated or standardised · Tests that decide who gets a drug are often not validated prospectively and are measured differently in every lab.
- Knowledge reaches practice too slowly · Knowledge diffusion is slow: it takes years for a proven result to change what most patients receive, and no one can keep up with the literature.