# Idylla CDx MSI Test

Source: https://onco.cc/drugs/idylla-cdx-msi/  
OnCo record `idylla-cdx-msi` (Test). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

A test that finds MSI-high bowel cancer, the group that can be treated with nivolumab alone or with ipilimumab.

## Summary

Biocartis's Idylla CDx MSI Test was approved on 15 August 2025 (PMA P250005) as the companion diagnostic for nivolumab, alone or with ipilimumab, in microsatellite instability-high colorectal cancer. The same day the FDA approved Agilent's MMR IHC Panel pharmDx for the same drugs, which reaches the same group by staining the mismatch repair proteins instead.

## Fields

- Kind: Test
- Status: approved
- Last checked: 2026-11-03
- Tags: test
- Brand: Idylla CDx MSI Test
- Modality: Nucleic acid companion diagnostic test (microsatellite instability, colorectal tumour tissue)
- Mechanism: Reads seven microsatellite markers (ACVR2A, BTBD7, DIDO1, MRE11, RYR3, SEC31A and SULF2) in colorectal tumour tissue to call microsatellite instability-high (MSI-H).
- Approvals: US 2025: Companion diagnostic for nivolumab alone or with ipilimumab in MSI-H colorectal cancer

## Sources

- FDA PMA P250005: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpma/pma.cfm?id=P250005
- FDA: List of cleared or approved companion diagnostic devices: https://www.fda.gov/medical-devices/in-vitro-diagnostics/list-cleared-or-approved-companion-diagnostic-devices-in-vitro-and-imaging-tools

## Connected records

- drugs: [Ipilimumab](https://onco.cc/drugs/ipilimumab/), [MMR IHC Panel pharmDx (Dako Omnis)](https://onco.cc/drugs/mmr-ihc-panel-pharmdx/), [Nivolumab](https://onco.cc/drugs/nivolumab/)
- biomarkers: [MSI-high (microsatellite instability by PCR or sequencing)](https://onco.cc/biomarkers/msi-high/)
- cancers: [Colorectal cancer](https://onco.cc/cancers/colorectal/)
- technologies: [Companion diagnostics](https://onco.cc/technologies/companion-diagnostic/)
- companies: [Biocartis](https://onco.cc/companies/biocartis/)
- terms: [Companion diagnostic](https://onco.cc/terms/companion-diagnostic-term/), [Microsatellite instability (MSI-H) / mismatch repair deficiency (dMMR)](https://onco.cc/terms/msi/)

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