Lynparza belongs to a class of drugs called PARP inhibitors that block an enzyme involved in repairing damaged DNA. By blocking the enzyme, the DNA in cancer cells may be less likely to be fixed, leading to the death of those cells and potentially a slowdown or halt in tumor growth, the FDA said.
The drug, also known as olaparib, is marketed by AstraZeneca and Merck.
The agency said its approval was based on a randomized clinical trial of more than 300 advanced breast cancer patients with BRCA 1 or BRCA 2 mutations. The trial found that the length of time during which the tumors did not grow significantly, a measure called progression-free survival, was a median of 7 months for patients treated with Lynparza compared to 4.2 months for patients receiving chemotherapy only. Lynparza didn't improve the overall length of survival, however.
When those results were published last June, Mark Robson, an oncologist at Memorial Sloan Kettering Cancer Center who led the multisite trial, described the treatment as “an early chapter in a woman's journey” dealing with breast cancer — one that can delay the start of chemotherapy and help preserve her quality of life.
In an interview Friday, he called the drug an “exciting new option” for patients with BRCA-caused cancer. “It's a building block,” he said, adding that researchers now need to determine whether results can be improved by using it in combination with other treatments.
The FDA on Friday also approved Myriad Genetics' diagnostic test, called BRACAnalysis CDx, as a companion to Lynparza. The test, which was previously cleared for ovarian cancer patients, identifies which breast cancer patients have BRCA mutations.
The National Cancer Institute estimates that about 253,000 women will be diagnosed with breast cancer this year and that more than 40,000 will die of the disease. About 5 percent to 10 percent of patients with breast cancer have a BRCA mutation.