Abstract OT3-05-03: POLARIS: Palbociclib (P) in hormone receptor-positive (HR+) advanced breast cancer: A prospective multicenter noninterventional study

Abstract

Abstract Background: P is a novel cyclin-dependent kinase 4/6 inhibitor approved in the United States and Canada in combination with endocrine therapy for HR+/human epidermal growth factor receptor 2–negative (HER2-) advanced breast cancer (ABC). Despite promising trial results, not all patients respond to P. Moreover, despite a median age at diagnosis of 62 years, elderly patients are underrepresented in targeted therapy trials, including the PALOMA studies assessing P. It is important to understand P use in real-world practice settings, including tolerability and outcomes in the vulnerable older population. In addition, understanding the mechanisms of P response or resistance is critical to identify clinical factors and biomarkers that can predict which patients will benefit from P. This multicenter observational and biomarker study will seek to address these and other data gaps. Trial Design: This is a prospective, noninterventional study of 1500 patients treated with P from 100 US and 10 Canadian sites. Study duration will span 2 years of recruitment and 3 years of follow-up after P treatment, until patient withdrawal from the study or death. Study participation is not intended to alter routine treatment; all treatment decisions, including type and timing of disease monitoring, are at the discretion of the treating physician and patient. Eligibility: Eligible patients are aged ≥18 years with a diagnosis of adenocarcinoma of the breast with (1) evidence of advanced or metastatic disease not amenable to treatment with curative intent, (2) documented HR+/HER2- status, and (3) planned treatment with P. Patients with a life expectancy <3 months at initial diagnosis, those participating in interventional trials, and those receiving active treatment for malignancies other than ABC at enrollment are ineligible. Aims: In a large real-world cohort of HR+/HER2- ABC patients treated with P in routine clinical practice, this study aims to assess the following: prescribing and treatment patterns for ABC before, during, and after P therapy; overall clinical response to P; biomarker assessment investigating potential mechanisms of response and resistance to P based on genomic analyses of blood samples; patient quality of life, as measured by the European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire Core 30; geriatric assessments in patients aged ≥70 years at enrollment based on the G8 Geriatric Screening Tool and the Activities of Daily Living questionnaire; and sequencing of treatment for metastatic disease. Other outcomes to be assessed include survival and toxicity. Methods: Data will be collected from routine clinical assessments. Patients will have the option to provide blood samples drawn at standard-of-care intervals at baseline, during P treatment, and at the end of treatment for potential biomarker identification. Analyses will be primarily descriptive, with point estimates and confidence intervals as well as Kaplan-Meier methods used to assess time-to-event outcomes. Accrual: Presently, 46 patients from 20 sites are enrolled. Funding: Pfizer Inc. Citation Format: Tripathy D, Bardia A, Blum JL, Rocque G, Wilks S, Lakhanpal S, Migas J, Cappelleri J, Perkins J, Comstock G, Wang Y. POLARIS: Palbociclib (P) in hormone receptor-positive (HR+) advanced breast cancer: A prospective multicenter noninterventional study [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT3-05-03.