FDA Approves Companion Diagnostic for Niraparib in Advanced Ovarian Cancer

The FDA has approved the MyChoice CDx test as a companion diagnostic for niraparib (Zejula) for patients with advanced ovarian cancer, according to a press release from the developer, Myriad Genetics, Inc.¹

MyChoice CDx is now the only FDA-approved companion diagnostic test for niraparib to identify treatment-eligible patients with homologous recombination deficiency (HRD)-positive status. Investigators highlighted that it determines HRD status through next generation sequencing of BRCA1/2 genes and tumor genomic instability score. The tumor genomic instability score includes loss of heterozygosity, telomeric allelic imbalance, and large-scale state transitions.

Supporting data came from the randomized, double-blind phase 3 PRIMA trial (NCT02655016), which assessed niraparib maintenance therapy vs placebo among patients with stage III or IV ovarian cancer who completed front-line platinum-based chemotherapy. In PRIMA, MyChoice CDx was used to determine HRD status and stratify patients.

“The FDA approval reinforces Myriad’s long-standing leadership in ovarian cancer diagnostics and underscores the clinical importance of comprehensive HRD testing,” Brian Donnelly, chief commercial officer of Myriad Genetics, said in the press release.¹ “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.”

Initial results were published in New England Journal of Medicine in September 2019, with final overall survival (OS) results from the PRIMA trial published in Annals of Oncology in November 2024.^2,3

As of the May 17, 2019, data cutoff, the median progression-free survival (PFS) was 13.8 months with niraparib vs 8.2 months with placebo in the overall population (HR, 0.62; 95% CI, 0.50-0.76; P <.001); in the HRD population, the median PFS was 21.9 months vs 10.4 months, respectively (HR, 0.43; 95% CI, 0.31-0.59; P <.001).

With a median follow-up of 6.2 years, the median OS was 46.6 months with niraparib compared with 48.8 months with placebo; the HR for OS for niraparib vs placebo was 1.01 (95% CI, 0.84-1.23; P = .8834).³ Since the OS was not statistically significant, formal testing did not proceed to the HRD population. The OS HR was 0.95 (95% CI, 0.70-1.29) in the HRD population and 0.93 (95% CI, 0.69-1.26) in the homologous recombination proficient (HRP) population.

Eligible patients on the trial were 18 years or older with newly diagnosed, histologically confirmed advanced cancer of the ovary, peritoneum, or fallopian tube, all of which were high-grade serous or endometroid tumors defined as stage III or IV.

Prior to enrollment, all patients had received 6 to 9 cycles of front-line platinum-based chemotherapy which resulted in either a complete or partial response. From all patients, tumor samples underwent central testing via MyChoice CDx to identify who had HRD status, defined as the presence of a BRCA deleterious mutation, a score of 42 on the MyChoice test, or both.

The primary end point of the trial was PFS in patients with HRD status and in the overall population. Secondary end points included OS, time until first subsequent therapy, PFS2, pharmacokinetics, and patient-reported outcomes.

Safety findings showed that the most common grade 3 or higher adverse events (AEs) with niraparib were anemia (31.0%), thrombocytopenia (28.7%), and neutropenia (12.8%).² Dose reductions and treatment discontinuations occurred in 70.9% and 12.0% of the niraparib group. The primary causes for discontinuation were myelosuppressive AEs, which were infrequent. No deaths occurred during treatment with niraparib as of data cutoff.

Previously, in April 2020, results from the PRIMA trial supported the FDA’s approval of niraparib for the maintenance treatment of adults with advanced epithelial ovarian, fallopian tube, or primary peritoneal cancer who are in a complete or partial response to first-line platinum-based chemotherapy.⁴

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. March 17, 2026. Accessed March 18, 2026. https://tinyurl.com/5h4ckre5
2. González-Martín A, Pothuri B, Vergote I, et al. Niraparib in patients with newly diagnosed advanced ovarian cancer. N Engl J Med. 2019;381(25):2391-2402. doi:10.1056/NEJMoa1910962
3. Monk BJ, Barretina-Ginesta MP, Pothuri B, et al. Niraparib first-line maintenance therapy in patients with newly diagnosed advanced ovarian cancer: final overall survival results from the PRIMA/ENGOT-OV26/GOG-3012 trial. Ann Oncol. 2024;35(11):981-992. doi:10.1016/j.annonc.2024.08.2241
4. FDA approves niraparib for first-line maintenance of advanced ovarian cancer. News release. FDA. April 29, 2020. Accessed March 18, 2026. https://tinyurl.com/232ffp4t