AI-Powered Research

1. A history of histological proven AR-positive (i.e. >10% staining), HER2-negative metastatic breast cancer (preferably assessment on fresh metastasis biopsy, alternatively archival metastasis biopsy)
2. Tumor progression after at least one line of systemic treatment
3. Measurable disease according to RECIST 1.1; or evaluable disease
4. Age * 18 years
5. Postmenopausal status defined as one of the following:
* Age *60 years
* Previous bilateral oophorectomy
* Age <60 years and amenorrhea for >12 months in the absence of interfering hormonal therapies (such as LH-RH agonists and ER-antagonists
* Age <60 years using ER antagonists should have amenorrhea for >12 months and FSH >24U/L and LH>14U/L
6.Adequate hematological, renal and liver function as follows:
*Absolute neutrophil count >1.5 x 109/L
*Platelet count >100 x 10^9/L
* White blood cell count >3 x 10^9/L
*AST and ALT <5.0 x upper limit of normal (ULN)
*Creatinine clearance >50mL/min
*Protrombin time, partial tromboplastin time and INR <1.5 x ULN
7. Written informed consent

Exclusion Criteria

1.Unable to comply with the protocol
2.Evidence of symptomatic central nervous metastases
3.Presence of life-threatening visceral metastases
4.Corrected QT interval (QTc) >500millliseconds at screening
5.Recent history of cardiac disease, including myocardial infarction, unstable angina pectoris or uncontrolled arrhythmia within 6 months prior to screening; or evidence of severe congestive heart failure with New York Heart Association severity classification > class I.
6.Recent history of trombo-embolic events within 6 months prior to screening
7.Hepatic impairment (Child-Pugh Class B or C)
8.Severe concurrent disease, infection, co morbid condition that, in the judgment of the investigator would make the patient inappropriate for enrollment
9.The concomitant use of strong CYP3A4 inhibitors (see table 1)
10.Previous anti-androgen treatment
11.Concurrent use of ER-directed anti hormonal therapies
12.Toxicity of radiotherapy or major surgery not resolved before baseline PET scanning

Study & Design

Study Type: Interventional

Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
<p>The percentage difference in 18F-FDHT uptake in tumor lesions after 4 weeks of<br /><br>monotherapy bicalutamide. A minimum decrease of 20% in 18F-FDHT uptake after 6<br /><br>weeks compared to baseline uptake, with an alpha of 0.05 and a power of 80%, is<br /><br>considered clinical significant. </p><br>

Secondary Outcome Measures

Name	Time	Method
<p>The difference in change in 18F-FDHT uptake after 4 weeks between those<br /><br>patients with a response and those without response.<br /><br>Relation of AR-expression and 18F-FDHT tracer uptake.<br /><br>Relation of change in AR availability and different subgroups (i.e. luminal A,<br /><br>luminal B, triple negative). </p><br>