Abstract OT3-05-04: A randomized, open-label, multi-center phase IV study evaluating palbociclib plus endocrine treatment versus a chemotherapy-based treatment strategy in patients with hormone receptor-positive, HER2-negative metastatic breast cancer in a real world setting (PADMA)

Background: Although endocrine therapy (ET) is recommended as first-line therapy for hormone receptor (HR)-positive, HER2-negative metastatic breast cancer (MBC) up to 50% of patients receive chemotherapy in this setting. Meanwhile new targeted treatment options for combination with ET have been developed and endocrine-based therapy with the CDK4/6 inhibitor Palbociclib (P) improves the progression free survival (PFS) of ET alone by about 50%. So far, there is no data comparing chemotherapy with or without maintenance ET and ET in combination with P as first-line therapy. Patients included in clinical trials are often criticized not to mirror the general breast cancer population and every-day clinical practice due to rigid inclusion and exclusion criteria, limited number of treatment options, strict monitoring intervals and study assessments. Methods: PADMA trial is a so called low intervention trial with no rigid inclusion and exclusion criteria, and study assessments.Patients with first-line HR+/HER2- MBC who are candidate for mono-chemotherapy will be eligible to receive either P plus ET per label or mono-chemotherapy per investigator´s choice with or without maintenance ET (1:1 randomization). Primary objective is to compare the time-to-treatment failure (TTF) for patients randomized to receive the mono-chemotherapy treatment strategy versus those randomized to receive P and ET. TTF is defined as time from randomization to discontinuation of treatment due to disease progression, treatment toxicity, patient9s preference, or death. Main secondary objectives are progression free survival, overall survival at 36 months, amongst other time to event endpoints as well as toxicity and compliance. All patients receive a specific mobile device (PADMA-Phone) and a validated wearable device (ActiWatch) in order to collect data regarding sleep and activity levels, patient well-being and health care utilization (number and duration of phone calls, and patient visits to investigator site) for assessment of daily monitoring treatment impact (DMTI). Results: Overall, 360 patients will be accrued to show an improved TTF for P in combination with ET compared to mono-chemotherapy of investigator´s choice with or without maintenance ET. Recruitment will start in QIII/2017 and is planned for approximately 18 months in 100 sites in Germany, Spain, Poland, Italy, France, UK and Canada. Conclusions: The aim of PADMA is to demonstrate that an endocrine-based strategy consisting of ET plus P is superior to a chemotherapy-based strategy as first-line therapy in women with HR+/HER2- MBC in a real world setting. Assessment of patient-reported outcome, health care utilization, and sleep and activity levels will deliver important information on the differences between endocrine-based and chemotherapy-based treatment. Citation Format: Loibl S, Barinoff J, Seiler S, Decker T, Denkert C, Hardy-Bessard A-C, Senkus-Konefka E, Cognetti F, Palmieri C, Gelmon K, Luebbe K, Furlanetto J, Mueller V, Mundhenke C, Schmidt M, von Minckwitz G, Uhlig M, Burchardi N, Thill M. A randomized, open-label, multi-center phase IV study evaluating palbociclib plus endocrine treatment versus a chemotherapy-based treatment strategy in patients with hormone receptor-positive, HER2-negative metastatic breast cancer in a real world setting (PADMA) [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 OT3-05-04.