Discontinuation of CDK4/6 inhibitors in patients with metastatic HR positive, HER2 negative breast cancer with durable disease control: A randomized low-intervention phase II trial of the AIO working groups breast cancer and quality of life

Prior treatment

• Patient has contraindication or shows hypersensitivity to the existing treatment with CDK4/6 inhibitor plus endocrine therapy
• Patient has significant cardiovascular disease, such as cardiac disease (New York Heart Association Class II or greater), myocardial infarction or cerebrovascular accident within 6 months prior to initiation of study treatment, unstable arrhythmias, or unstable angina
• Patient participated in another clinical study with an investigational medicinal product during the last 28 days before treatment initiation or 7 half-lives of previously used trial medication, whichever is longer or participate in such a study at the same time as this trial

Other illness

• Patient has active (or history of) brain or leptomeningeal metastases
• Any co-existing medical condition that in the investigator’s judgement will substantially increase the risk associated with the patient’s participation in the study

Lab values

• Patient shows evidence of any other disease, neurologic or metabolic dysfunction, physical examination finding or laboratory finding giving reasonable suspicion of a disease or condition that contraindicates the use of any of the study medications, puts the patient at higher risk for treatment-related complications or may affect the interpretation of study results

Age

• Patient has other concomitant or previous malignancy, except adequately treated in-situ carcinoma of the uterine cervix, basal or squamous cell carcinoma of the skin, cancer in complete remission for > 5 years

Other

• Patient is pre- or perimenopausal. Patient is pregnant or breast feeding or planning to become pregnant within five times the half-life of the IMP after the end of treatment.
• Patient who has been incarcerated or involuntarily institutionalized by court order or by the authorities
• Patients who are unable to consent because they do not understand the nature, significance and implications of the clinical trial and therefore cannot form a rational intention in the light of the facts

• Female patient has given written informed consent
• Patients considered postmenopausal
• Patient is ≥ 18 years of age at time of signing the written informed consent
• Patient has been diagnosed with histologically confirmed metastatic adenocarcinoma of the breast
• Patient has documented histological or cytological confirmation of estrogen receptor positive (ER+) and HER2 negative (HER2-) disease
• Patient has no curative treatment option by surgery or radiotherapy
• Patient was treated with CDK4/6 inhibitor plus endocrine therapy for at least 12 months with disease control (complete remission, partial remission or stable disease) as judged by the treating physician before planned study treatment initiation
• Patient has a preserved performance status (ECOG ≤ 2)
• Patient has adequate bone marrow, renal and hepatic function