The experimental medicine veliparib improved progression-free survival for people with a BRCA1 or BRCA2 mutation diagnosed with locally advanced or metastatic breast cancer that was either:
- hormone-receptor-positive and HER2-negative
The research is part of the virtual program of the European Society of Medical Oncology Breast Cancer Meeting 2020. Read the abstract of “Veliparib plus carboplatin-paclitaxel in patients with HER2-negative advanced/metastatic gBRCA-associated breast cancer: Results in hormone receptor-positive and triple-negative breast cancer subgroups from the phase III BROCADE3 trial.”
The term “gBRCA” means the mutation in the BRCA1 or BRCA2 gene is a germline mutation that has been inherited from a parent and is in all your DNA.
Triple-negative breast cancer is:
Advanced-stage breast cancer is either locally advanced breast cancer or metastatic breast cancer. Locally advanced breast cancer is breast cancer that has spread to tissue near the breast, but not to parts of the body away from the breast. Metastatic breast cancer is breast cancer that has spread to parts of the body away from the breast, such as the bones or liver.
Progression-free survival is how long a person lives without the cancer growing.
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, the study wanted to see if adding veliparib to the chemotherapy regimen of Taxol (chemical name: paclitaxel) and carboplatin would increase progression-free survival in people with a BRCA1 or BRCA2 mutation diagnosed with advanced-stage HER2-negative breast cancer.
All the people had been treated with at least two treatment regimens for advanced-stage disease.
For this analysis, the researchers looked specifically at two subgroups of people in the study:
- 266 people diagnosed with advanced-stage hormone-receptor-positive, HER2-negative breast cancer
- 243 people diagnosed with advanced-stage triple-negative breast cancer
In the hormone-receptor-positive subgroup:
- 174 people were treated with veliparib, Taxol, and carboplatin
- 92 people were treated with Taxol, carboplatin, and a placebo pill that looked just like veliparib but contained no medicine
Progression-free survival was:
- 13 months for people treated with veliparib, Taxol, and carboplatin
- 12.5 months for people treated with only Taxol and carboplatin
This difference was statistically significant, which means that it was likely due to the difference in treatments and not just because of chance.
The researchers also looked at overall survival, which is how long the people lived, whether or not the cancer grew.
Overall survival was:
- 32.4 months for people treated with veliparib, Taxol, and carboplatin
- 27.1 months for people treated with only Taxol and carboplatin
This difference wasn’t statistically significant, which means that it could have been due to chance and not because of the difference in treatment.
In the triple-negative subgroup:
- 163 people were treated with veliparib, Taxol, and carboplatin
- 80 people were treated with Taxol, carboplatin, and placebo
Progression-free survival was:
- 16.6 months for people treated with veliparib, Taxol, and carboplatin
- 14.1 months for people treated with only Taxol and carboplatin
This difference also was statistically significant.
Overall survival was:
- 35 months for people treated with veliparib, Taxol, and carboplatin
- 30 months for people treated with only Taxol and carboplatin
Like the overall survival results for the hormone-receptor-positive subgroup, this difference wasn’t statistically significant.
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 in the BROCADE3 trial were:
- low levels of neutrophils and leukocytes, two types of white blood cells
- low red blood cell counts
- low levels of platelets, blood cells that help blood clot
Overall, the risk of low red and white blood cell counts, nausea, and diarrhea was 5% higher in people treated with veliparib compared to people treated only with Taxol and carboplatin.
“In both subgroups, the benefit of veliparib was durable with an increased probability of remaining progression free at 2 and 3 years compared with placebo,” said Jean-Pierre Ayoub, M.D., lead author of the BROCADE3 study and assistant professor of medicine at the University of Montreal in Montreal, Quebec, Canada, in an interview.
What this means for you
The results from the BROCADE3 trial 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 advanced 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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