FDA Approves MyChoice CDx as Companion Diagnostic for Niraparib for Ovarian Cancer

The FDA has approved the MyChoice® CDx test as the companion diagnostic for niraparib (Zejula), a PARP inhibitor. This approval establishes MyChoice CDx as the first and only FDA-approved companion diagnostic in the United States used to identify patients with advanced ovarian cancer who are homologous recombination deficiency (HRD) positive and thus eligible for treatment with niraparib.¹

The approval is supported by data from the PRIMA clinical trial (NCT02655016),² which utilized the MyChoice CDx test to stratify patients based on their HRD status. By leveraging next-generation sequencing to assess both BRCA1/2 genes and genomic instability, the test offers a more comprehensive identification of eligible patients compared to traditional methods.

The Role of MyChoice CDx

The MyChoice CDx test is designed to provide critical genomic insights that guide treatment decisions for patients with advanced epithelial ovarian, fallopian tube, or primary peritoneal cancer. Its primary function is to determine a patient’s HRD status, which is the key indicator for the efficacy of PARP inhibitor therapy.¹

Unlike other tumor tests that rely solely on percent loss of heterozygosity (%LOH), MyChoice CDx conducts a broad evaluation. It utilizes next-generation sequencing to analyze:

• BRCA1 and BRCA2 genes (including large rearrangements).
• A tumor genomic instability score comprising 3 biomarkers: LOH, telomeric allelic imbalance, and large-scale state transitions.

The MyChoice CDx test is capable of identifying 34% more patients with HRD than tests using %LOH alone, ensuring a wider range of patients can access targeted therapy.

It is the only HRD test specifically mentioned in the American Society of Clinical Oncology (ASCO) guidelines for the selection of ovarian cancer patients who may benefit from PARP inhibitors.

Niraparib is an oral, once-daily poly (ADP-ribose) PARP inhibitor. Its mechanism of action involves preventing DNA repair within tumor cells, which ultimately leads to cell death.

Approved Indications in the United States

The FDA has approved niraparib for specific maintenance treatments in adult patients:

• First-line maintenance: For patients with advanced epithelial ovarian, fallopian tube, or primary peritoneal cancer who have shown a complete or partial response to first-line platinum-based chemotherapy and whose cancer is HRD-positive (defined by deleterious BRCA mutations or genomic instability).
• Recurrent cancer maintenance: For patients with deleterious or suspected deleterious germline BRCA-mutated recurrent ovarian cancer who are in response to platinum-based chemotherapy.

The FDA approval of MyChoice CDx as the companion diagnostic for niraparib represents a significant milestone in ovarian cancer care. By providing a comprehensive assessment of HRD status through the analysis of BRCA1/2 and genomic instability, Myriad Genetics provides a validated tool for identifying patients most likely to benefit from PARP inhibitor therapy.

“The FDA approval reinforces Myriad’s long-standing leadership in ovarian cancer diagnostics and underscores the clinical importance of comprehensive HRD testing,” said Brian Donnelly, chief commercial officer of Myriad Genetics, in a news release. “By enabling precise identification of patients who may benefit from PARP inhibitors, MyChoice CDx helps ensure that treatment decisions are guided by robust genomic insights.”

REFERENCES

1.Myriad Genetics receives FDA approval of the MyChoice CDx Test as the companion diagnostic for Zejula (niraparib) for patients with ovarian cancer. News release. Myriad Genetics. Published March 17, 2026. Accessed March 18, 2026. https://tinyurl.com/46vkndmn

2.A study of niraparib (GSK3985771) maintenance treatment in participants with advanced ovarian cancer following response on front-line platinum-based chemotherapy. ClinicalTrials.gov. Updated March 10, 2026. Accessed March 18, 2026. https://clinicaltrials.gov/study/NCT02655016