Real-world study of patients with germline BRCA1/2-mutated human epidermal growth factor receptor 2‒Negative advanced breast cancer: Patient demographics, treatment patterns, adverse events, and physician-reported satisfaction in the United States, Europe, and Israel

Background: Current guidelines for the treatment of human epidermal growth factor receptor 2‒negative (HER2-) advanced breast cancer (ABC) are informed by tumor characteristics and include platinum- and non-platinum-based chemotherapy, chemotherapy plus immunotherapy, endocrine monotherapy, or endocrine therapy plus a targeted therapy. In addition, poly(adenosine diphosphate-ribose) polymerase inhibitors (PARPi) have recently demonstrated improved clinical and patient-reported outcomes and manageable toxicity profiles compared with chemotherapy in patients with germline breast cancer susceptibility gene 1 or 2 (gBRCA1/2)‒mutated HER2- ABC in clinical trials and are now approved to treat this patient population. This study provides complementary real-world data regarding treatment patterns, adverse events, and physician-reported treatment satisfaction in this population.

Methods: This retrospective analysis using the Adelphi Real World ABC Disease Specific Programme in the United States, European Union, and Israel included patients aged ≥18 years receiving therapy for stage IIIb or IV gBRCA1/2-mutated HER2- ABC. Oncologists completed a patient record form detailing patient demographics, clinical assessments, and treatment history and a survey regarding their use of and satisfaction with treatments.

Results: Among the 543 patients, mean age was 55 years, 25% were premenopausal, 70% had hormone receptor‒positive (HR+) ABC, and 30% had triple-negative breast cancer (TNBC). PARPi were used in 5%, 11%, and 12% of first-line, second-line, and third-line therapies, respectively, for patients with HR+ ABC; for TNBC, percentages were 18%, 44%, and 36%. Across treatment lines, neutropenia, anemia, and nausea occurred in 16%, 24%, and 32% of patients receiving PARPi, respectively; 22%, 38%, and 33% of patients receiving platinum chemotherapy; and 20%, 20%, and 33% of patients receiving non-platinum-based chemotherapy. Physician satisfaction was highest with PARPi and with chemotherapy plus immunotherapy.

Conclusions: Findings in this real-world population complement clinical trial observations and provide further support for treatment of patients with PARPi in gBRCA1/2-mutated HER2- ABC.