Impact of eHealth-support on Quality of Life in Metastatic Breast Cancer Patients Treated With Palbociclib and Endocrine Therapy

This is a multicenter (80 sites) , randomized, parallel-group, Phase IV clinical trial with the primary objective of testing the hypothesis of superiority for time to deterioration (TTD) in patients using the ePRO system CANKADO active over CANKADO inform version. Eligible patients will have histologically or cytologically proven diagnosis of hormone receptor positive (HR+), human epidermal growth factor receptor 2 (HER2)- negative locally advanced or metastatic breast cancer and will be either candidates to receive palbociclib in combination with aromatase inhibitor or candidates to receive palbociclib in combination with fulvestrant for their locally advanced or metastatic disease. Patients who are candidates for palbociclib in combination with aromatase inhibitor (AI) or fulvestrant will not be candidates for curative therapies. For Patients who are candidates for palbociclib in combination with aromatase inhibitor or fulvestrant one prior line of chemotherapy for locally advanced or metastatic breast cancer is allowed in addition to a maximum of two lines of endocrine therapy. Patients will be stratified according their eligibility of receiving palbociclib with endocrine therapy (AI or fulvestrant) as first or later lines. Patients allocated to the combination of palbociclib with aromatase inhibitor will receive: * Palbociclib, 125 mg, orally once daily on Day 1 to Day 21 of every 28-day cycle followed by 7 days off treatment and * Aromatase inhibitor, orally once-daily (continuously). * Pre- or peri-menopausal patients should additionally receive a Gonadotropin-Releasing-Hormon (GnRH)-agonist Patients allocated to the combination of palbociclib with fulvestrant will receive: * Palbociclib, 125 mg, orally once daily on Day 1 to Day 21 of every 28-day cycle followed by 7 days off treatment and * Fulvestrant , 500 mg, intramuscularly on Days 1 and 14 of Cycle 1, every 28 days (± 7 days) thereafter starting. * Pre- or peri-menopausal patients should additionally receive a Gonadotropin-Releasing-Hormon (GnRH)-agonist Patients of each treatment group (palbociclib / aromatase inhibitor and palbociclib/fulvestrant) will randomized 2:1 in the Intervention Arm A CANKADO active is the fully functional CANKADO-based eHealth treatment support service, including a high density observation of patient reported outcome (HDOB-PRO). And in the Control Arm B CANKADO inform stands for a CANKADO-based eHealth service with a personal login. On-site surveys without feedback functions for the patient will be available. CANKADO inform will be used for the initial ePRO and further on-site ePROs. Patients can login from at home and can document their drug intake. Further features will not be available. Patients will continue to receive study treatment together with the assigned ePRO assessment until investigator assessed disease progression, symptomatic deterioration, unacceptable toxicity, death, or withdrawal of consent, whichever occurs first. In addition, should palbociclib related toxicity mandate discontinuation; patients can continue to receive fulvestrant alone. Patients discontinuing the active treatment phase will enter a follow-up period phase during survival further progression and new anti-cancer therapy information will be collected once a year up to 48 month after randomization. In addition biomarkers will be assessed as a scientific program within this study. Tumor material (tumor tissue and Blood samples (plasma and serum)) will be collected. Tumor tissue from available primary tumor and available biopsies from recurrent disease will be collected. Blood samples will be collected at four time points (cycle 1 (C1D1), after 2 weeks (C1D14), after 12 weeks (C4D1), and upon progression (End of treatment).