Untersuchung von Metformin bei Patienten mit kastrationsresistentem Prostatakarzinom in Kombination mit Enzalutamide vs. Enzalutamide alleine

Drug: Enzalutamide;Drug: Metformin

Gender: Male
Maximum age: N/A
Minimum age: 18 Years

Inclusion Criteria:

- Written informed consent according to ICH/GCP regulations before registration and
prior to any trial-related investigations

- Histologically or cytological confirmed adenocarcinoma of the prostate without small
cell carcinoma or small cell components

- Asymptomatic or minimally symptomatic patients in relation to disease

- Metastatic adenocarcinoma of the prostate documented by imaging (CT/MRI and/or bone
scan)

- Ongoing androgen deprivation therapy with Gonadotropin-releasing hormone GnRH
analogues or bilateral orchiectomy (i.e. surgical or medical castration)

- Total testosterone levels = 1.7 nmol/L (corresponding to = 50 ng/dL)

- Tumor progression at the time of registration, defined as per protocol.

- Completed baseline QoL and pain questionnaires

- Male patients = 18 years

- WHO performance status 0-2

- Adequate hematologic values: hemoglobin = 90 g/L, neutrophils = 1.0 x 109/L, platelets
= 75 x 109/L

- Adequate hepatic function: ALT and AST = 2.5 x ULN, bilirubin = 1.5 x ULN (exception
if Gilbert's syndrome = 2.5 x ULN)

- Adequate renal function: calculated creatinine clearance = 50 mL/min, according to the
formula of Cockcroft-Gault

- Patient is able to swallow the trial drugs and comply with trial requirements

- Patient agrees not to father a child during participation in the trial and during 3
months thereafter

- Patient agrees to participate to the mandatory translational research part of the
trial with exception of Pyruvate dehydrogenase sub-study.

Exclusion Criteria:

- Known or suspected Central nervous system CNS metastases or active leptomeningeal
disease

- Previous malignancy within 2 years prior to registration, with the exception of
localized non-melanoma skin cancer and Ta and Tis bladder cancer

- Prior treatment for prostate cancer with

- novel endocrine agents (including abiraterone acetate, enzalutamide, TAK-700,
TAK-683, TAK-448, VT464, darolutamide, apalutamide),

- radioisotopes,

- TKI and other small molecules,

- immunotherapy,

- chemotherapy (with the exception of docetaxel chemotherapy in hormone sensitive
prostate cancer)

- Treatment with experimental drugs or treatment within a clinical trial within 30 days
prior to registration (except the clinical trial SAKK 96/12, PEACE-4 and/or the
biobank project SAKK 63/12)

- Clinically significant cardiovascular disease including:

- Myocardial infarction within 6 months prior to registration,

- Uncontrolled angina within 3 months prior to registration,

- Congestive heart failure NYHA class III or IV,

- QTc interval > 480 ms,

- History of clinically significant ventricular arrhythmias (e.g. ventricular
tachycardia, ventricular fibrillation, torsades de pointes),

- History of Mobitz II second or third degree heart block without a permanent
pacemaker in place,

- Uncontrolled hypertension as indicated by systolic blood pressure > 170 mmHg OR
diastolic blood pressure > 105 mmHg

- Severe concurrent disease, infection, or co-morbidity that, in the judgment of the
investigator, would make the patient inappropriate for enrollment (e.g. uncontrolled
or acute severe infection, advanced chronic obstructive pulmonary disease, heart
failure)

- Known history of HIV, hepatitis B, hepatitis C

- Major surgery within 4 weeks prior to registration

- Gastrointestinal disorder affecting absorption (e.g., gastrectomy, active peptic ulcer
disease within 3 months prior to registration)

- Treatment with metformin within the last 6 months prior to registration

- Patients on pharmacotherapy for diabetes mellitus

- History of diabetic ketoacidosis, diabetic coma and pre-coma

- Known history of seizures or any conditions that may predispose to seizure. History of
loss of consciousness or transient ischemic attack within 12 months prior to
registration

- Concurrent anticoagulation with rivaroxaban or warfarin

- Known hypersensitivity to the IMPs or hypersensitivity to any of their components

- Any concomitant drugs contraindicated for use with the IMPs according to the
Swissmedic approved product information

- Any psychological, familial, sociological or geographical condition potentially
hampering compliance with the trial protocol and follow-up.