Talazoparib in Patients with a Germline BRCA‐Mutated Advanced Breast Cancer: Detailed Safety Analyses from the Phase III EMBRACA Trial

Background In the EMBRACA phase III study (NCT01945775), talazoparib was associated with a significantly prolonged progression‐free survival (PFS) compared with physician's choice of chemotherapy (PCT) in germline BRCA1/2‐mutated HER2‐negative advanced breast cancer (ABC). Herein, the safety profile of talazoparib is explored in detail. Materials and Methods Overall, 412 patients received ≥1 dose of talazoparib (n = 286) or PCT (n = 126). Adverse events (AEs) were evaluated, including timing, duration, and potential overlap of selected AEs. The relationship between talazoparib plasma exposure and grade ≥3 anemia was analyzed. Time‐varying Cox proportional hazard models assessed the impact of dose reductions on PFS. Patient‐reported outcomes (PROs) in patients with common AEs and health resource utilization (HRU) were assessed in both treatment arms. Results The most common AEs with talazoparib were hematologic (195 [68.2%] patients) and typically occurred within the first 3–4 months of receiving talazoparib. Grade 3‐4 anemia lasted approximately 7 days for both arms. Overlapping grade 3‐4 hematologic AEs were infrequent with talazoparib. Higher talazoparib exposure was associated with grade ≥3 anemia. Permanent discontinuation of talazoparib due to hematologic AEs was low (