# myChoice CDx

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

## TL;DR

A tumour test that measures DNA-repair scarring so that women with ovarian cancer beyond BRCA carriers can benefit from PARP inhibitors.

## Summary

Approved 23 October 2019 (PMA P190014) with niraparib for homologous-recombination-deficient ovarian cancer after several lines of therapy, and in May 2020 as the companion diagnostic for olaparib plus bevacizumab first-line maintenance in HRD-positive ovarian cancer (PAOLA-1). Roughly half of high-grade serous ovarian cancers are HRD-positive by this definition, about twice the BRCA-mutated fraction. The scar is permanent, so a tumour can remain HRD-positive after it has developed resistance, one reason the test predicts benefit better in first-line than in later lines.

## Fields

- Kind: Treatment
- Status: approved
- Last checked: 2026-09-10
- Tags: test
- Brand: myChoice CDx
- Modality: Tumour HRD genomic instability companion diagnostic test
- Mechanism: Tumour BRCA1/2 sequencing combined with a genomic instability score (GIS) built from loss of heterozygosity, telomeric allelic imbalance and large-scale state transitions; GIS ≥42 or a BRCA mutation defines HRD-positive.
- Approvals: US 2019: Companion diagnostic for niraparib in HRD-positive advanced ovarian cancer; US 2020: Companion diagnostic for olaparib plus bevacizumab first-line maintenance in HRD-positive ovarian cancer

## Notes

- What a result means: HRD-positive (by genomic instability score or BRCA mutation) means adding a PARP inhibitor after chemotherapy is likely to delay relapse; HRD-negative means the benefit is much smaller.
- Triple-negative breast cancer: the 42 genomic instability threshold was derived in TNBC platinum trials (Telli 2016) and HR deficiency by this definition was 70.5% in GeparSixto (Loibl 2018), but the score did not predict carboplatin benefit in TNT (Tutt 2018) and the assay has no breast indication.

## Sources

- FDA PMA P190014: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpma/pma.cfm?id=P190014

## Connected records

- cancers: [Ovarian cancer](https://onco.cc/cancers/ovarian/), [Triple-negative breast cancer (TNBC)](https://onco.cc/cancers/tnbc/)
- technologies: [Companion diagnostics](https://onco.cc/technologies/companion-diagnostic/), [HRD & BRCA testing](https://onco.cc/technologies/hrd-testing/), [HRD genomic scar scores (GIS, LOH, HRDetect)](https://onco.cc/technologies/hrd-genomic-scar-scores/)
- targets: [BRCA1 / BRCA2 (HRD)](https://onco.cc/targets/brca/), [PARP](https://onco.cc/targets/parp/)
- drugs: [Niraparib](https://onco.cc/drugs/niraparib/), [Olaparib](https://onco.cc/drugs/olaparib/)
- companies: [Myriad Genetics](https://onco.cc/companies/myriad-genetics/)
- terms: [Homologous recombination deficiency (HRD)](https://onco.cc/terms/hrd/)
- trials: [PAOLA-1 / ENGOT-ov25](https://onco.cc/trials/paola-1/), [PRIMA / ENGOT-OV26](https://onco.cc/trials/prima/)
- key papers: [Carboplatin in BRCA1/2-mutated and triple-negative breast cancer BRCAness subgroups: the TNT Trial](https://onco.cc/key-papers/paper-tutt-nat-med/), [Homologous recombination deficiency (HRD) score predicts response to platinum-containing neoadjuvant chemotherapy in patients with triple-negative breast cancer](https://onco.cc/key-papers/paper-telli-hrd-score-platinum-tnbc-ccr-2016/), [Survival analysis of carboplatin added to an anthracycline/taxane-based neoadjuvant chemotherapy and HRD score as predictor of response-final results from GeparSixto](https://onco.cc/key-papers/paper-loibl-geparsixto-survival-hrd-ann-oncol-2018/)
- biomarkers: [HRD-positive (genomic instability score)](https://onco.cc/biomarkers/hrd-positive/), [Tumour (somatic or germline) BRCA1/2 mutation and HRR gene alterations](https://onco.cc/biomarkers/brca-somatic/)

---
JSON: https://onco.cc/api/v1/entities/mychoice-cdx.json