Talazoparib for People with Metastatic Breast Cancer Who Have Acquired (Somatic) BRCA Mutations

About the Study

This is a study for patients with metastatic breast cancer without a known mutation in BRCA1 or BRCA2, who learn they have a BRCA1 or BRCA2 acquired tumor mutation (somatic mutation) found through liquid biopsy. Patients are treated with talazoparib, a well-tolerated oral PARP inhibitor that targets the BRCA1/2 mutation to determine whether this treatment (which is already approved for people with an inherited BRCA1/2 mutation) is effective in this population.

Type of Study

This is a phase 2, open-label, single arm, multi-center clinical trial evaluating talazoparib in patients with metastatic breast cancer who have somatic BRCA1/2 mutations detectable in cell-free DNA. Patients with triple-negative (TNBC) or hormone receptor positive/HER2 negative (HR+/HER2-) breast cancer are eligible. Patients are treated with talazoparib until disease progression, unacceptable toxicity, or withdrawal of consent.

• This is an open-label, single arm study so all patients get the same study treatment (talazoparib).

What the Study Involves

• Initial screening for study (baseline blood work, CT scans and bone scan, visit, consent, etc.)
• Treatment with talazoparib, an oral therapy, until disease progression, toxicity, or withdrawal of consent. Talazoparib is already FDA approved for germline BRCA1/2 carriers.
• Blood draw every 4 weeks for organ function assessment and to evaluate changes in cell-free DNA (liquid biopsy) with treatment.
• CT Chest, abdomen, and pelvis and bone scan every 12 weeks while on treatment.

Patients may participate if they have the following:

• metastatic breast cancer
  • If they have TNBC they must have received at least 1 prior line of chemotherapy (any number of prior therapies are allowed), OR
  • If they have HR+/HER2- breast cancer, they must have received at least 1 prior hormone therapy (or considered inappropriate for hormone therapy) in the metastatic setting
• a liquid biopsy test (cell-free DNA testing) , which found an acquired (somatic) BRCA1 or BRCA2 mutation
• Patients are not required to have had prior genetic testing for an inherited BRCA1/2 mutation. However, those patients who have completed genetic testing and have an inherited BRCA1/2 mutation are not eligible.
• adequate organ function

• Patients are excluded if they have an inherited BRCA1 and BRCA2 mutation.
• Patients are excluded if they have received a PARP inhibitor in the past.