Myriad Genetics Submits myChoice HRD as Companion Diagnostic for Niraparib

Myriad Genetics this week submitted the first part of its application to the FDA for the myChoice HRD CDx test, a companion diagnostic for the poly (ADP-ribose) polymerase (PARP) inhibitor niraparib, sold by Tesaro/GlaxoSmithKline as Zejula.

The test is a companion diagnostic to identify certain patients with ovarian, fallopian, or primary peritoneal cancer who could be treated with niraparib. These patients have received 3 or more lines of therapy and were sensitive in their last round of chemotherapy. Their tumors have a BRCA mutation or are BRCA wild type, and they have homologous recombination deficiency (HRD) in DNA repair.

Niraparib is 1 of 3 PARP inhibitors approved by the FDA to treat ovarian and other genetically driven cancers. Recent updates to the National Comprehensive Cancer Network (NCCN) guidelines upgraded the role of testing in the treatment of ovarian cancer. The guidelines specifically say that HRD testing should be considered.

PARP inhibitors are targeted therapies that block the PARP protein that would otherwise repair the DNA in patients with HRD in cancer cells. Because these cells cannot be repaired, they die. When used in the right patients, PARP inhibitors are helping to improve survival rates in ovarian cancer, which is one of the deadliest cancers for women, claiming 14,000 lives a year.

“This submission of myChoice HRD CDx to the FDA is a major milestone for Myriad’s companion diagnostic program in oncology and our first indication for a tumor-based test,” Nicole Lambert, president of Myriad Oncology, said in a statement. “In clinical studies, the myChoice HRD test effectively identified heavily pre-treated patients with ovarian, fallopian or primary peritoneal cancer who are likely to benefit from Zejula. We believe myChoice HRD CDx can help inform therapy selection and potentially improve outcomes for patients.”

The FDA filing for niraparib in this indication is based on findings from the QUADRA study. Patients in the fourth and fifth line of treatment whose myChoice test was positive and who were sensitive in their last round of chemotherapy had a confirmed objective response rate of 28% (P = 0.0005), with a median duration of response of 9.2 months.