Abstract PD7-10: Randomized, multicenter phase II trial of weekly paclitaxel with or without the oral selective aurora kinase A (AURKA) inhibitor, Alisertib, in patients with ER+ HER2- metastatic breast cancer
Authors: O'Shaughnessy Joyce , McIntyre Kristi , Wilks Sharon , Ma Ling , Fintel William , Block Margaret , Andorsky David , Danso Michael , Koutrelakos Nicholas , Locke Tracy , Scales Amy , Steckel Lauren , Wang Yunfei 
Published: March 2020

Abstract
Elevated expression of AURKA adversely affects prognosis in ER+ breast cancer and is associated with resistance to taxanes, endocrine therapy, and PI3K inhibitors. A recent randomized phase II trial of combined paclitaxel plus alisertib (P+A) in recurrent ovarian cancer patients (pts) showed improved progression-free survival (PFS) compared to paclitaxel (P) alone (Falchook G. JAMA Oncol 2019). We conducted a randomized phase II trial of P alone versus P+A in pts with ER+ HER2- metastatic breast cancer (MBC). Methods: The primary objective of the trial was PFS in the intent-to-treat (ITT) population with secondary endpoints of overall survival (OS), overall response rate (ORR), clinical benefit rate (CBR; CR+PR+SD&gt;6 mos), safety and analysis of archival breast cancer for molecular predictors of benefit from alisertib. ER+ HER2- MBC pts who had had prior endocrine therapy, 0 or 1 prior chemotherapy regimens for MBC, &gt; 12 mos treatment-free interval from neo/adjuvant taxane therapy, and who had measurable or evaluable lytic bone disease were randomized to receive P 90 mg/m2 IV D1, 8, 15 on a 28-day cycle or P 60mg/m2 D1, 8, 15 plus A 40 mg PO BID D1-3, 8-10, 15-17 on a 28-day cycle until disease progression or unacceptable toxicity. Pts were stratified by prior neo/adjuvant taxane (yes/no) and by whether they were receiving first (1L)- or second (2L)-therapy for MBC. Proportions of ORR and CBR were compared using Chi-square test between the two study arms. Kaplan-Meier estimator was applied to estimate OS and PFS and univariate Cox regression was used to assess the hazard ratio of study treatment. Results: 139 pts were randomized (69 to P+A; 70 to P) in the US Oncology Network between 2/2015 and 2/2018 and 136 pts received treatment on trial. At data cut-off, 76% of pts had had a documented PFS event and the median followup was 19.7 mos. The median age was 62 and 69% of pts received trial therapy as 1L treatment; 41% had had prior neo/adjuvant taxane therapy. Median PFS in the ITT population was 10.2 mos with P+A vs 7.1 mos with P alone, HR 0.56, 95% CI 0.37-0.84, p=0.005. Median OS was 29.8 mos with P+A vs 24.4 mos with P alone, HR 0.85, p=0.486. ORR and CBR in the response evaluable population were 31% and 67%, respectively, in the P+A arm vs 34% and 57%, respectively, in the P alone arm (p&gt;0.05). Grade 3/4 adverse events (AEs) occurred in 83% of P+A pts vs 47% with P alone. The main grade 3/4 AEs with P+A vs P were neutropenia 59% vs 15%, anemia 10% vs 1%, febrile neutropenia 1.5% vs 0, diarrhea 11% vs 0, stomatitis 15% vs 0, peripheral neuropathy 1.5% vs 9%. 1 pt died of sepsis with P+A. Conclusions: Addition of oral A to weekly P significantly improved PFS, the primary endpoint, compared with P alone, and toxicity with P+A was manageable with A dose reduction. These data support further evaluation of alisertib in ER+ HER2- MBC pts.
Citation Format: Joyce O'Shaughnessy, Kristi McIntyre, Sharon Wilks, Ling Ma, William Fintel, Margaret Block, David Andorsky, Michael Danso, Nicholas Koutrelakos, Tracy Locke, Amy Scales, Lauren Steckel, Yunfei Wang. Randomized, multicenter phase II trial of weekly paclitaxel with or without the oral selective aurora kinase A (AURKA) inhibitor, Alisertib, in patients with ER+ HER2- metastatic breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr PD7-10.