Abstract P1-19-36: Exploratory analysis of TreatER+ight; a Canadian prospective real-world observational study in HR+ advanced breast cancer

Background: TreatER+ight is the 1st prospective observational study in Canadian HR+ HER2- advanced breast cancer patients currently receiving endocrine therapy (ET) alone or in combination with targeted therapy (TT) (NCT02753686). Methods: This exploratory analysis displays real-world evidence on baseline demographics, treatment patterns, sequencing, and method of access to therapy. More specifically this abstract focuses on treatment decisions around CDK4/6-based therapy at various lines of treatment. At data cut-off of April 1st 2019, 305 patients were enrolled from 24 sites since Mar916 with 113 patients receiving CDK4/6is at baseline. 300 patients were evaluable for treatment analysis. Results: Conclusions: The majority of patients enrolled (66.6%) are receiving combination therapy with the most common treatment being a CDK4/6-based therapy (56.5%). Of the patients receiving CDK4/6 at baseline a majority are receiving this therapy in the 1L (53.1%) and 2L (33.6%), with the median duration on therapy of respectively 8.87 and 8.77 months. For patients receiving CDK4/6 therapy in 1L, the most common 2L treatment is either endocrine therapy single agent and in certain parts of the country everolimus + exemestane. Further sequencing information will be analyzed and shared for this abstract. Citation Format: Catherine Doyle, Nadia Califaretti, Cristiano Ferrario, Nayyer Iqbal, John Hilton, Theodore Vandenberg, Mihaela Mates, Vivian Glenns, Swati Kulkarni, Puneet Bains, Sina Haftchenary, Sabrina Perri, Stephen Chia. Exploratory analysis of TreatER+ight; a Canadian prospective real-world observational study in HR+ advanced 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 P1-19-36.