Efficacy And Safety Of Talazoparib (Tala) Or Physician'S Choice Of Therapy (Pct) In United States Patients (Pts) With Her2-Germline Brca1/2-Mutated (Gbrcam) Locally Advanced/Metastatic Breast Cancer (La/Mbc) In The Embraca Study.

1044 Background: TALA is a poly(ADP-ribose) polymerase (PARP) inhibitor approved in the US for HER2- g BRCAm LA/MBC. Approval was based on results from the Phase 3 EMBRACA trial comparing efficacy/safety of TALA (1 mg/d) to PCT (capecitabine, eribulin, gemcitabine, vinorelbine) in HER2- g BRCAm LA/MBC pts. This analysis describes outcomes in US pts included in the pivotal study. Methods: Clinical findings from US pts enrolled in EMBRACA were analyzed. Pt characteristics, progression-free survival (PFS), objective response rate (ORR), clinical benefit rate (CBR), and safety/adverse events (AEs) were among the parameters assessed. Results: Of 431 randomized pts, 156 pts (36%) were from the US (TALA: 99; PCT: 57). Pt characteristics were balanced, although a higher percentage in the TALA arm had more poor prognostic features (eg, triple-negative breast cancer, disease-free interval < 12 mo, and more disease sites). TALA improved PFS, ORR, CBR, and duration of response (DOR) vs PCT (Table). 22% of pts in the TALA arm had a continued objective response at month 12 vs 0 pts in the PCT arm. The most common AEs in the TALA arm included anemia, neutropenia, thrombocytopenia, fatigue, nausea, alopecia, and headache; hematologic grade 3/4 AEs occurred more often than nonhematologic AEs. Conclusions: In US pts with HER2- g BRCAm LA/MBC, TALA demonstrated significant improvements in outcomes vs PCT with a manageable safety profile. Clinical trial information: NCT01945775. [Table: see text]