Research table: PARP inhibitors and treatment for metastatic breast cancer

This summary table contains detailed information about research studies. Summary tables are a useful way to look at the science behind many breast cancer guidelines and recommendations. However, to get the most out of the tables, it’s important to understand some key concepts. Learn how to read a research table.

Introduction: Olaparib (Lynparza) and talazoparib (Talzenna) are poly(ADP-ribose) polymerase (PARP) inhibitors. PARP inhibitors are only used in breast cancer treatment for people who have a BRCA1 or BRCA2 (BRCA1/2) inherited gene mutation.

Olaparib and talazoparib are used to treat HER2-negative metastatic breast cancer in people who have a BRCA1/2 inherited gene mutation and have been treated with chemotherapy in the past (including chemotherapy for early breast cancer).

If the metastatic breast cancer is hormone receptor-positive, people should have also been treated with hormone therapy in the metastatic setting.

Compared to treatment with chemotherapy, treatment with olaparib or talazoparib may give people with a BRCA1/2 inherited gene mutation who have HER2-negative metastatic breast cancer more time before the cancer spreads.

Learn more about olaparib and talazoparib in the treatment of metastatic breast cancer, including their side effects.

PARP inhibitors and genetic testing for BRCA1 and BRCA2 inherited gene mutations

The National Comprehensive Cancer Network recommends everyone with metastatic breast cancer get BRCA1/2 genetic testing to see if a PARP inhibitor may be used for treatment [1].

Learn more about genetic testing.

Study selection criteria: Randomized clinical trials with 100 or more participants with a BRCA1/2 inherited gene mutation who had HER2-negative metastatic breast cancer.


Study Population
(number of participants)

Drug(s) Used

Objective Response Rate—Percent who Responded to Treatment
(95% CI)

Overall Survival
Better with
PARP Inhibitor Compared to Chemotherapy

Randomized clinical trials

OlympiAD trial [1]


Olaparib alone





Chemotherapy alone
(capecitabine, eribulin, or vinorelbine)



EMBRACA trial [2]


Talazoparib alone





Chemotherapy alone
(capecitabine, eribulin, gemcitabine or vinorelbine)



NS = No statistically significant difference between the 2 treatment groups

* People who got olaparib were just as likely to die (from breast cancer or other causes) as those who got chemotherapy, with a hazard ratio of 0.90 (95% CI, 0.63–1.29).

† People who got talazoparib were just as likely to die (from breast cancer or other causes) as those who got chemotherapy, with a hazard ratio of 0.76 (95% CI, 0.55–1.06).


  1. Robson M, Im SA, Senkus E, et al. Olaparib for metastatic breast cancer in patients with a germline BRCA mutation. N Engl J Med. 377(6):523-533, 2017.
  2. Litton JK, Rugo HS, Ettl J, et al. Talazoparib in patients with advanced breast cancer and a germline BRCA mutation. N Engl J Med. 379(8):753-763, 2018.

Updated 07/07/22