Lynparza, a PARP inhibitor, also increased by two-thirds the time it took for breast cancer to progress after treatment— seven months, versus 4.2 with chemo, researchers said.
BRCA mutations are responsible for 3 percent of breast cancer worldwide. The cases are very difficult to treat, and many women with the mutations decide to remove their breasts before developing signs of the cancer.
AstraZeneca discussed Phase 3 clinical trial results of Lynparza’s ability to treat breast cancer at the annual meeting of the American Society of Clinical Oncology in Chicago. The convention, which started June 2, finished June 6.
The presentation was titled “OlympiAD: Phase III trial of olaparib monotherapy versus chemotherapy for patients (pts) with HER2-negative metastatic breast cancer (mBC) and a germline BRCA mutation (gBRCAm).”
The trial included 302 women with breast cancer that had spread to other organs. All had a BRCA mutation.
Lynparza reduced the risk of the cancer increasing by as much as 42 percent, compared with standard chem, researchers discovered.
In addition, tumors shrank in 60 percent of the patients receiving Lynparza, versus 29 percent of women on chemotherapy. Another key finding was that it took seven months for women on Lynparza to have their disease progress, versus 4.2 months for those on chemo.
Researchers said 37 percent of the Lynparza patients experienced serious side effects. That was a sizable figure, but considerably less than the 50 percent seen in women who received chemotherapy.
Lynparza is known as a PARP inhibitor, and here’s how it works:
BRCA genes use a particular machinery to correct errors in DNA. Cells with BRCA mutations use a different machinery, and need help in their repair effort from proteins called PARP enzymes.
Preventing PARPs from aiding in the BRCA mutation repair effort leads to an accumulation of DNA errors that kills cancer cells.
Lynparza prevents PARP from helping with the repair, which is why it’s called a PARP inhibitor.
AstraZena is studying Lynparza’s long-term impact on breast cancer patients in another trial, called PARTNER, according to a press release. The company said it will share the trial results soon.