People diagnosed with metastatic HER2-negative breast cancer with a BRCA1 or BRCA2 mutation treated with experimental veliparib and chemotherapy lived about 2 months longer without the cancer growing if they continued on veliparib after stopping chemotherapy, according to a study. Chemotherapy was stopped for reasons other than the cancer growing.
The research was published online on Aug. 27, 2020, by The Lancet Oncology. Read the abstract of “Veliparib with carboplatin and paclitaxel in BRCA-mutated advanced breast cancer (BROCADE3): a randomised, double-blind, placebo-controlled, phase 3 trial.”
Veliparib is a type of medicine called a PARP inhibitor. The PARP enzyme fixes DNA damage in both healthy and cancer cells. PARP inhibitors have been shown to work against breast cancer with a BRCA1 or BRCA2 mutation by making it very difficult for these cancer cells to fix DNA damage.
Right now, two PARP inhibitors have been approved to treat metastatic HER2-negative breast cancer with a BRCA1 or BRCA2 mutation:
- Lynparza (chemical name: olaparib)
- Talzenna (chemical name: talazoparib)
Lynparza, Talzenna, and veliparib are all pills taken by mouth.
About the study
Called the BROCADE3 trial, this analysis of the study wanted to see if continuing on veliparib after chemotherapy was stopped for reasons other than the breast cancer growing would improve progression-free survival for people diagnosed with metastatic HER2-negative breast cancer with a BRCA1 or BRCA2 mutation. Progression-free survival is how long a person lives without the cancer growing.
This analysis included 509 people diagnosed with metastatic HER2-negative breast cancer with a BRCA1 or BRCA2 mutation who had received up to two previous rounds of chemotherapy for metastatic breast cancer.
The people were randomly assigned to two treatment groups:
- 337 people received veliparib plus the chemotherapy combination of carboplatin and Taxol (chemical name: paclitaxel)
- 172 people received a placebo pill that looked just like veliparib but contained no medicine, plus carboplatin and Taxol
If any of the people in the study stopped chemotherapy for a reason besides the cancer growing, they could continue taking either veliparib or the placebo pill until the cancer grew.
Anyone in the study in the placebo arm could receive veliparib if the cancer grew after stopping chemotherapy.
Half the people were followed for longer than about 3 years and half were followed for shorter periods of time.
Progression-free survival was:
- 14.5 months for people taking veliparib
- 12.6 months for people taking the placebo
This slight difference was statistically significant, which means that it was likely due to the difference in medicine and not just because of chance.
"The results of this phase III trial show that, when added to carboplatin and paclitaxel, and continued as monotherapy if carboplatin and paclitaxel were discontinued before disease progression, veliparib resulted in a durable improvement in progression-free survival, with benefit evident at 2 years and 3 years after randomization in patients with advanced HER2-negative breast cancer and a germline BRCA1 or BRCA2 mutation," the researchers wrote.
Veliparib side effects
Like almost all cancer medicines, veliparib can cause side effects, some of them severe. The most common serious side effects (grade 3 or higher) caused by veliparib plus chemotherapy in this analysis were:
- low levels of neutrophils, a type of white blood cell
- low red blood cell counts
- low levels of platelets, blood cells that help blood clot
Serious side effects happened in 34% of people treated with veliparib and chemotherapy compared to 29% of the people treated with only chemotherapy.
What this means for you
The results from this analysis of BROCADE3 data are encouraging. Still, it’s important to remember that veliparib is not approved by the U.S. Food and Drug Administration to treat breast cancer, and it’s not clear when or if it will be approved.
If you know you have a BRCA1 or BRCA2 mutation and have been diagnosed with advanced-stage HER2-negative breast cancer, it makes sense to talk to your doctor about whether a PARP inhibitor such as Lynparza or Talzenna is right for you and your unique situation.
If you’ve been diagnosed with advanced-stage HER2-negative breast cancer and have not had genetic testing, it’s a good idea to ask your doctor about genetic testing to see if Lynparza or Talzenna would make sense for you.
To talk with others who have been diagnosed with metastatic disease, join the Breastcancer.org Discussion Board forum Stage IV and Metastatic Breast Cancer ONLY.
Written by: Jamie DePolo, senior editor
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