Treating Early-Stage HER2-Negative Breast Cancer with a PARP Inhibitor (Niraparib) and Immunotherapy (Dostarlimab) in People with a BRCA or PALB2 Mutation

About the Study

This study will look at how well the drugs Niraparib (a PARP inhibitor) and Dostarlimab (an immunotherapy) treat early-stage breast cancer in people with an inherited BRCA1, BRCA2 or PALB2 mutation. 

What the Study Entails

The study will have three different groups of participants (Group A, Group B and Group C). Participants in each group will receive both study drugs. The timing of the drugs differs by group. The study is open label, which means that all participants will know which group they are assigned to.

This study is open to participants with triple-negative breast cancer and participants with ER-positive breast cancer. Participants with triple negative breast cancer will be randomized (randomly assigned) to one of two treatment arms (Group A or Group B).

• Group A: Participants will receive Niraparib together with Dostarlimab for 18 weeks
• Group B: Participants will receive Niraparib alone for 3 weeks, followed by Niraparib with Dostarlimab for 15 weeks

All participants with ER-positive breast cancer will be placed into Group C.

• Group C: Participants will receive Niraparib with Dostarlimab for 18 weeks

Participants will receive treatment for 18 weeks. After 18 weeks, participants will be evaluated to determine if they are a candidate for surgery or if they will require additional treatment.

Study Sites

Massachusetts

Boston, MA

• Massachusetts General Hospital      
  Contact: Steven Isakoff, MD, PhD by phone: 617-726-6500 or by email at: [email protected]     
• Beth Israel Deaconess Medical Center         
  Contact: Nadine Tung, MD by phone: 617-667-7081 or by email at: [email protected]        
• Dana-Farber Cancer Institute
  Contact: Erica L Mayer, MD MPH by phone: 617-632-3800 or by email at: [email protected]     

To participate, people must have the following diagnosis:

• Have Stage 1, Stage 2 or Stage 3 HER2-negative breast cancer. 
• Have a primary tumor size of at least 1.5 cm that has not been removed at the time of enrollment.
• Have an inherited BRCA1, BRCA2 or PALB2 mutation.
• Women are not pregnant and are not wanting to breastfeed while participating in this study.
• Must be willing to undergo a biopsy at baseline and after 3 weeks on study treatment.

People with the following may not participate:

• Have Stage IV (metastatic) breast cancer
• Have a primary tumor that is HER2-positive
• Have received prior treatment for the current breast cancer
• Have an autoimmune disease that has required systemic treatment within the past 2 years
• Have an uncontrolled infection, severe heart disease, uncontrolled major seizure disorder, or other defined study condition that would limit compliance with study requirements.