Poly (adenosine diphosphate-ribose) polymerase inhibitors (PARP)i are emerging as standard oncology treatments in various tumor types. The indications will expand as PARPi are being investigated in various breast cancer subtypes. Currently, except for BRCA1/2 mutation carriers with human epidermal growth factor receptor 2 (HER2)-negative breast cancer, there is inadequate identification of predictive biomarkers of response. We present a 57-year-old woman with metastatic breast cancer, hormone-receptor-positive, HER2 negative with a germline ataxia-telangiectasia mutation with a large brain metastasis with clinical benefit to talazoparib. This case report exemplifies the importance of the multidisciplinary management of patients with brain metastases and personalized biomarker selected treatment.
Keywords: PARPi; ataxia-telangiectasia mutation (ATM); brain metastasis; breast cancer; precision medicine.