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    Companion Diagnostic

    IVD that identifies patients who will benefit from a specific drug.

    Reviewed by Christian Espinosa, Founder, Blue Goat CyberLast reviewed May 5, 2026

    Definition

    A companion diagnostic is an IVD device co-developed with a therapeutic and required (per the drug label) to select patients eligible for treatment - for example, HER2 testing for trastuzumab or PD-L1 testing for pembrolizumab.

    What this means in practice

    Co-developed with pharma; FDA reviews drug and CDx approvals together. Growing tail of pan-tumor and signature-based CDx (e.g., MSI-H, TMB-high) tied to immunotherapy.

    Cross-references

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    Closely related context worth reading.

    Mentioned in recent activity

    1 entry

    Primary references

    3 sources
    Link health: 2 verified 1 bot-blocked· last checked 2026-05-09
    FDA·1MedTech Europe·1MedTech Dive·1
    1. 1
      FDA CDx list
      Bot-blocked
      FDAfda.gov
    2. 2
      MedTech Europe - Facts & Figures
      Verified
      MedTech Europemedtecheurope.org
    3. 3
      MedTech Dive
      Verified
      MedTech Divemedtechdive.com

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