NEW YORK (GenomeWeb) – The US Food and Drug Administration has approved Myriad Genetics' BRACAnalysis CDx as a complementary diagnostic to identify ovarian cancer patients with germline BRCA mutations who are likely to benefit most from treatment with Zejula (niraparib).
The FDA approved Tesaro's PARP inhibitor Zejula as a maintenance treatment for recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer after patients' tumors have shrunk with platinum-based chemotherapy. The National Cancer Institute estimates that 22,000 women will be diagnosed with these cancers this year, and more than 14,000 will die of these diseases.
The 553-patient randomized study that supported the approval of the drug and complementary diagnostic showed that when patients had a germline BRCA mutation, they experienced median progression-free survival of 21 months on Zejula compared to 5.5 months on placebo. Those without a BRCA mutation also benefitted, however, with a median progression-free survival of 9.3 months on Zejula compared to 3.9 months on placebo.
After these results from the NOVA study were presented last year, Tesaro said it would pursue market approval for its PARP inhibitor in the overall recurrent ovarian cancer population. In approving the drug with a complementary test, instead of a companion diagnostic, the agency has also recognized in the data that Zejula benefits patients with and without BRCA mutations.
"Zejula offers patients a new treatment option that may help delay the future growth of these cancers, regardless of whether they have a specific genetic mutation," Richard Pazdur, acting director of the Office of Hematology and Oncology Products in FDA's drug division, said in a statement announcing the approval of Zejula.
A companion diagnostic, according to the FDA, is necessary for the safe and effective use of a drug, and when a drug is approved with such a test, the label generally mentions its availability. A complementary test can help guide treatment strategy and identify which patients likely to derive the greatest benefit from therapy, but isn't required. The indication section of Zejula's label doesn't mention BRCA testing, though the clinical studies section details the drug's efficacy in patients with and without BRCA mutations, and the use of BRACAnalysis CDx to statify patients.
Myriad's BRACAnalysis CDx, which uses PCR and Sanger sequencing, was the first lab-developed test the FDA approved as a companion diagnostic, alongside AstraZeneca's ovarian cancer drug Lynparza (olaparib). Now, BRACAnaysis CDx is also the only LDT to have FDA approval as a complementary test.
Meanwhile, Tesaro had also used Myriad's myChoice HRD CDx — which gauges patients homologous recombination deficiency status — to assess responses in the NOVA study and found that HRD-positive patients had a median progression-free survival of 12.9 months on Zejula and 3.8 months on placebo. And an exploratory analysis showed that HRD negative patients derived benefit from the PARP inhibitor as well, with a median progression-free survival of 6.9 months compared to 3.8 months on placebo.
Myriad has submitted myChoice HRD CDx for approval, as well, and spokesperson Ron Rogers said that the FDA is still reviewing the premarket approval submission for the next-generation sequencing test. "We remain optimistic about the clinical utility and commercial potential of companion diagnostics for PARP inhibitors, and we continue to believe there will be a significant need for a biomarker," Myriad added in a statement.