38O - Talazoparib (TALA) vs physician’s choice of chemotherapy (PCT) in Asian patients (Pts) with HER2- advanced breast cancer (ABC) and a germline BRCA1/2 mutation (gBRCA1/2mut): Data from phase III EMBRACA

Abstract

BackgroundThe oral PARP inhibitor TALA is approved in multiple countries (US/EU/ARG/UAE) for HER2- gBRCA1/2mut ABC. To date, limited information is available on use of TALA in Asian pts. MethodsEMBRACA (NCT01945775) is an ongoing randomized study comparing TALA 1 mg/day vs PCT in HER2- gBRCA1/2mut ABC. Primary endpoint: progression-free survival (PFS) by blinded review; secondary endpoints: PFS by investigator; objective response rate (ORR); safety (adverse events [AEs]). Endpoints were assessed in Asian pts (APAC; Korea, Taiwan) and in the intent-to-treat (ITT) population. Results431 pts were randomized (TALA: ITT 287, APAC 23; PCT: ITT 144, APAC 10). In APAC pts, median age was 41.0 and 45.0 y in TALA and PCT, with 73.9% and 60.0% aged <50 y, respectively; ITT median age was 45.0 and 50.0 y, with 63.4% and 46.5% aged <50 y, respectively. In APAC pts, triple-negative (42.4%) and hormone-receptor–positive (57.6%) disease were consistent with ITT pts. TALA was more effective than PCT in APAC pts, similar to ITT pts (Table). In APAC pts receiving TALA, most common (≥10%) hematologic AEs were neutropenia (34.8%), anemia (17.4%), platelet count decrease (13.0%), thrombocytopenia (13.0%), and neutrophil count decrease (8.7%); common (≥30%) non-hematologic AEs were nausea (47.8%), fatigue (43.5%), URTI (30.4%), and decreased appetite (30.4%). AEs were generally consistent with ITT. Median relative dose intensity (actual-dose intensity/planned-dose intensity) for TALA was 99.7% APAC and 87.2% ITT. No APAC pts permanently discontinued due to AEs in either arm; 5.9% (TALA) and 8.7% (PCT) permanently discontinued due to AEs in ITT.Table38OTableTALA vs PCTAPACITTPFS by blinded review N PFS, median, mo HR (95% CI)23 vs 10 9.0 vs 7.1 0.740 (0.224-2.438)287 vs 144 8.6 vs 5.6 0.542 (0.413-0.711)PFS, investigator-assessed N PFS, median, mo HR (95% CI)23 vs 10 7.0 vs 4.8 0.697 (0.234-2.076)287 vs 144 7.0 vs 4.4 0.538 (0.420-0.689)ORR, unconfirmed N n (%) OR (95% CI)16 vs 8 10 (62.5) vs 2 (25.0) 1.88 (0.07-117.85)219 vs 114 137 (62.6%) vs 31 (27.2%) 4.99 (2.93-8.83)DOR N Median, mo Continued ORR at Month 12, %10 vs 2 9.5 vs 5.2 24 vs 0137 vs 31 5.4 vs 3.1 23 vs 0APAC, Asia-Pacific, specifically Korea and Taiwan; CI, confidence interval; DOR, duration of response; HR, hazard ratio; ITT, intent-to-treat; OR, odds ratio; ORR, objective response rate; PCT, physician’s choice of chemotherapy; PFS, progression-free survival; TALA, talazoparib. ConclusionsIn pts with HER2- gBRCA1/2mut ABC, TALA improved outcomes vs PCT. Results in a limited number of enrolled Asian pts were generally consistent with the ITT population. Clinical trial identificationNCT01945775. Editorial acknowledgementEditorial support, under the direction of the authors, was provided by Ann Gordon, PhD, of CMC AFFINITY, a division of McCann Health Medical Communications Ltd., Glasgow, UK, funded by Pfizer Inc. Legal entity responsible for the studyPfizer. FundingPfizer (Medivation). DisclosureK-H. Lee: Honoraria (institution), Advisory / Consultancy: Roche; Honoraria (institution), Advisory / Consultancy: AstraZenceca; Advisory / Consultancy: Bayer; Advisory / Consultancy: Ono pharmaceutical; Advisory / Consultancy: Samsung bioepis; Advisory / Consultancy: Eisai. S-B. Kim: Research grant / Funding (institution): Novartis. J. Sohn: Research grant / Funding (institution): MSD; Research grant / Funding (institution): Roche; Research grant / Funding (institution): Novartis; Research grant / Funding (institution): AstraZeneca; Research grant / Funding (institution): Lilly; Research grant / Funding (institution): Pfizer; Research grant / Funding (institution): Bayer; Research grant / Funding (institution): GSK; Research grant / Funding (institution): CONTESSA; Research grant / Funding (institution): Daiichi Sankyo. A. Goodwin: Travel / Accommodation / Expenses: Pfizer; Travel / Accommodation / Expenses: AstraZeneca; Travel / Accommodation / Expenses: Roche; Travel / Accommodation / Expenses: Novartis; Travel / Accommodation / Expenses: Amgen; Travel / Accommodation / Expenses: Celgene; Travel / Accommodation / Expenses: Boehringher. T. Usari: Shareholder / Stockholder / Stock options, Full / Part-time employment: Pfizer Inc. S. Lanzalone: Shareholder / Stockholder / Stock options, Full / Part-time employment: Pfizer Inc. All other authors have declared no conflicts of interest.