PET/CT and WB MRI for Staging and Response in CRPC Patients Receiving Enzalutamide

Study Overview
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Brief Summary
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The aim of the study is to assess the clinical utility of 18F-fluoro-deoxyglucose Positron Emission Tomography (PET)/Computed Tomography (CT) and Whole Body Magnetic Resonance Imaging (MRI) versus conventional bone scan and prostate-specific antigen (PSA) measurements in response prediction to treatment with Enzalutamide in castration-resistant prostate cancer patients. The study will assess how these 2 imaging modalities perform compared to traditional serial PSA measurements and bone scan in assessing metastatic tumour load, progressive disease and response to treatment with Enzalutamide in castration-resistant prostate cancer patients. In addition measurements of serially collected circulating tumour cell (CTC) samples, cell-free tumour DNA and RNA will be performed in order to evaluate their predictive value in terms of response measurement.

Detailed Description
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Castration-resistant prostate cancer patients eligible for 2nd line hormonal treatment will undergo treatment with Enzalutamide (XTANDI). Subjects will receive 1dd 160 mg Enzalutamide orally continuously until progressive disease occurs. All subjects will undergo 18F-FDG PET/CT scans at baseline, 2 weeks, 2 and 6, 9 and 12 months after starting androgen receptor-directed treatment. All subjects will undergo Whole Body MRI at baseline, 6, 9 and 12 months. Bone scans will be performed at baseline, 3 months, 6 and 12 months. PSA will be measured at baseline and every 4 weeks thereafter until at 12 months. CTC counts and characteristics will be measured at baseline and during Enzalutamide treatment.

Official Title
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A Phase 2, Open-label, Single-arm, Efficacy and Imaging Study of Oral Enzalutamide in Chemo-Naïve Patients With Progressive Prostate Cancer Who Have Failed Androgen Deprivation Therapy (Castration-resistant Prostate Cancer Patients)

Conditions
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Prostate Cancer Metastatic

Intervention / Treatment
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* Drug: Enzalutamide
* Device: 18-FDG PET/CT
* Device: Whole body MRI
* Device: Bone scan


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male aged 18 years or older; Histologically confirmed adenocarcinoma of the prostate without neuroendocrine differentiation or small cell features; Ongoing androgen deprivation therapy with a GnRH analogue or bilateral orchiectomy; Three consecutive rises of PSA, 1 week apart, resulting in two 50% increases over the nadir, with PSA of at least > 5 ng/mL but preferably >10 ng/mL; Progressive disease as defined by rising PSA levels plus by evidence of progressive and measurable soft tissue or bone disease by 18F-FDG PET/CT, Whole Body MRI or both; Castrate serum levels of testosterone < 50 ng/dL or < 1.7 nmol/L; Anti-androgen withdrawal for at least 6 weeks for bicalutamide, nilutamide or flutamide for at least 6 weeks; No prior treatment with cytotoxic chemotherapy; Eastern Cooperative Oncology Group (ECOG) score 0-2; A life expectancy of at least 12 months; Written informed consent. Exclusion Criteria: Severe concurrent disease, infection, or co-morbidity that, in the judgment of the Investigator, would make the patient inappropriate for enrolment; Known or suspected brain metastasis or active leptomeningeal disease; History of another malignancy within the previous 5 years other than curatively treated non melanomatous skin cancer; Total bilirubin, alanine aminotransferase (ALT) or aspartate aminotransferase (AST) 2.5 times the upper limit of normal at the Screening visit; Creatinine > 177 µmol/L (2 mg/dL) at the Screening visit; Hemoglobin <6 mmol/L, White blood cells < 4.0 x10^9/L, platelets < 100 x 10^9/L; History of seizure or any condition that may predispose to seizure. Also, history of loss of consciousness or transient ischemic attack within 12 months of enrolment (Day 1 visit); Contra-indication for MRI (e.g. pacemaker).

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Single arm<br>Subjects will receive 1 dd 160 mg Enzalutamide orally continuously until progressive disease occurs. Serial PSA measurements, PET/CT scans, Whole Body MRI, bone scans will be performed to assess metastatic tumour load, progressive disease and response to treatment. | Drug: Enzalutamide<br> <br> * Other names: Xtandi;Device: 18-FDG PET/CT<br> <br> Device: Whole body MRI<br> <br> Device: Bone scan<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Progression-Free Survival (PFS) at 6 months | Defined as the time from the date of randomization to the date of radiological progression or death (patients will be followed beyond the fixed time point of 12 months for continued response cq recurrence, but 12 month is the last fixed primary endpoint assessment). Radiological progression is defined by any of the following criteria: Soft tissue lesions: Progressive disease on 18F-FDG PET/CT or MRI by RECIST 1.1. Bone or bone marrow lesions: Progressive disease on PET/CT or MRI as evidenced by new lesions or an increase in size of 25% of the sum of target lesions. Conversion of the 18F-FDG PET signal of the metastases at 2 weeks, 2 or 6 months compared to baseline PET which by comparing it to PFS at 6 and 12 months may be an indicator or drug response. Radiological PFS at 6 months will be compared to a) PET signal conversion and to b) PSA measurements, and changes in number of lesions on the bone scan (conventional work up). | 6 months | 
| Progression-Free Survival (PFS) at 12 months | Defined as the time from the date of randomization to the date of radiological progression or death (patients will be followed beyond the fixed time point of 12 months for continued response cq recurrence, but 12 month is the last fixed primary endpoint assessment). Radiological progression is defined by any of the following criteria: Soft tissue lesions: Progressive disease on 18F-FDG PET/CT or MRI by RECIST 1.1. Bone or bone marrow lesions: Progressive disease on PET/CT or MRI as evidenced by new lesions or an increase in size of 25% of the sum of target lesions. Conversion of the 18F-FDG PET signal of the metastases at 2 weeks, 2 or 6 months compared to baseline PET which by comparing it to PFS at 6 and 12 months may be an indicator or drug response. Radiological PFS at 12 months will be compared to a) PET signal conversion and to b) PSA measurements, and changes in number of lesions on the bone scan (conventional work up). | 12 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Biochemical (PSA) response defined as prostate-specific antigen (PSA) nadir. | Response as PSA nadir. | 12 months | 
| PSA progression. PSA kinetics measured by PSA doubling time (regular PSA measurements). | PSA doubling time | 12 months | 
| Progression of bone lesions detected with bone scan according to Prostate Cancer Working Group 2 (PCWG2) criteria. | Progression of bone lesions | 6 and 12 months | 
| Radiologically confirmed spinal cord compression or pathological fracture due to malignant progression. | Radiological assessment of spinal cord compression or pathological fracture | 6 and 12 months | 
| Occurrence of Symptomatic Skeletal Events (SSE) evaluated by combination of clinical and radiological assessments | Assessment of external beam radiation therapy to relieve skeletal pain, occurrence of a new symptomatic pathologic bone fracture, spinal cord compression, tumour-related orthopedic surgical intervention or change of anti-neoplastic therapy to treat bone pain | 12 months | 
| Number of participants with change in CTC measurements correlated to radiological PFS. | Assessment of radiological PFS | 6 and 12 months | 
| Percent change from baseline in serum concentration of circulating testosterone (T). | Change in circulating testosterone | 12 months | 
| Percent change from baseline in serum concentration of dihydrotestosterone (DHT). | Change in serum concentration of dihydrotestosterone | 12 months | 
| Percent change from baseline in serum concentration of sex hormone binding globulin (SHBG). | Changes of SHBG | 12 months | 
| Percent change from baseline in serum concentration of androstenedione (A). | Changes of androstenedione from baseline | 12 months | 
| Number of participants with changes in biomarkers of bone turnover correlated to PSA. | Changes in biomarkers | 12 months | 
| Number of participants with adverse events (AEs) and serious adverse events (SAEs) leading to treatment discontinuation. | Assessment of AE and SAEs | 6 and 12 months | 
| Time to symptomatic progression (including death due to prostate cancer). | Time to progression | 12 months | 
| Time to initiation of salvage systemic therapy, including chemotherapy, or palliative radiation. | Time to chemotherapy or palliative radiation. | 12 months | 
| Quality of life measured by the Functional Assessment of Cancer Therapy-Prostate (FACT-P) questionnaire. | Quality of life assessment | 6 and 12 months | 
| Quality of life measured by the EuroQol 5-Dimension QoL Instrument (EQ-5D). | Quality of life assessment | 6 and 12 months | 
| Changes in Karnofsky score | Changes in Karnofsky score | 6 and 12 months | 
| Changes in visual analogue scale (VAS) for tumour-related pain. | Pain changes from baseline (QoL) | 6 and 12 months | 
| Changes in bone mineral density (BMD) as measured by Dual-energy X-ray absorptiometry (DXA) scan. | Bone mineral density changes | 6 and 12 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Castration-resistant prostate cancer, Enzalutamide, Imaging, PET/CT, Whole body MRI, Circulating tumour cells, Cell-free tumour DNA