# A reliance pathway for companion diagnostics so the test arrives with the drug

Source: https://onco.cc/ideas/idea-reg-diagnostic-reliance-pathway/  
OnCo record `idea-reg-diagnostic-reliance-pathway` (Idea). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Targeted cancer drugs often reach a country years before the test needed to select patients is approved there. Recognising other regulators' test approvals would close the gap.

## Summary

In vitro diagnostic regulation has fragmented further since the EU IVDR: a companion diagnostic cleared by FDA as a PMA needs a separate notified-body assessment in Europe and different routes in Japan, China and Brazil. Because the drug is unusable without the test, this delay is a drug access delay. The proposal is a reliance route under which a companion diagnostic approved alongside a drug by a WHO-listed authority is accepted for that indication, with local requirements limited to laboratory accreditation and proficiency testing.

## Fields

- Kind: Idea
- Last checked: 2026-09-08
- Hypothesis: Countries adopting diagnostic reliance reduce the gap between drug approval and reimbursed availability of its companion test from a median of over a year to under six months.
- Rationale: Analytical and clinical validation of a companion test does not vary by geography, and the test's clinical utility was already established in the pivotal drug trial that every regulator reviews.
- Proposed test: Survey the drug-to-test availability gap for ten recent targeted oncology approvals across 20 countries to size the problem; then pilot reliance in three countries and remeasure.
- Maturity: speculative
- Actor: regulator

## Sources

- Bottleneck evidence (Regulatory divergence between regions): FDA Oncology Center of Excellence, Project Orbis: https://www.fda.gov/about-fda/oncology-center-excellence/project-orbis

## Connected records

- technologies: [Companion diagnostics](https://onco.cc/technologies/companion-diagnostic/)
- terms: [Companion diagnostic](https://onco.cc/terms/companion-diagnostic-term/)
- bottlenecks: [Biomarkers are not validated or standardised](https://onco.cc/bottlenecks/b-biomarker-validation/), [Regulatory divergence between regions](https://onco.cc/bottlenecks/b-regulatory-fragmentation/)

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