About this trial
The goal of this phase 3 clinical trial is to determine the clinical effectiveness and cost effectiveness of using lower doses of Androgen Receptor Pathway Inhibitors (ARPI) to treat patients with prostate cancer that has spread (metastasized). The main questions it aims to answer are:
1. if overall survival for reduced dose ARPI is not worse than standard dose ARPI when treating patients with metastatic prostate cancer, and 2. that fatigue (extreme exhaustion) and not stopping ARPI permanently (due to adverse effects) are better than average with the reduced dose.
Participants will:
* Be randomised to take full dose (100%) of ARPI or half dose (50%) of ARPI. * Receive standard of care ADT. * Be on treatment for approximately 3 years according to standard of care. * Have clinic assessments and visits in clinic or remotely, as per their treating hospital's standard routine local practice in line with standard of care. Additional visits are not expected. * Complete quality of life questionnaires at week 0 (pre-treatment) and weeks 4, 16, 32, 48 and 64. * Keep a diary of their symptoms.
Translational research samples will be collected as follows:
* Blood samples at week 0 (pre-treatment) and weeks 24, 32, 48 and at disease progression. * Urine samples at week 0 (pre-treatment) and week 24 and at disease progression. * FFPE Tumour: Routinely collected diagnostic blocks. The duration of follow-up is approximately 3 years after the last patient is recruited (minimum follow-up is 3 years; maximum follow-up is approximately 6 years for the the first patient recruited) and the trial is expected to complete August 2032 (Last Patient Last Visit).
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
Adult males (male sex at birth) aged 18 years or older
Newly histologically or cytologically diagnosed prostate cancer (adenocarcinoma) that is metastatic hormone-sensitive (mHSPC) or metastatic castration resistant prostate cancer (mCRPC), for whom ARPI in combination with androgen deprivation is clinically planned
Prior ADT use for prostate cancer (including bilateral orchidectomy and transcutaneous oestrogen), is permitted provided: (a) ADT has been started less than 12 weeks prior to randomisation in mHSPC, (b) In the adjuvant setting the completion of adjuvant hormonal therapy was >12 months prior to randomisation and total duration is capped at 36 months total
ECOG performance status 0-2
Disqualifiers
Pathology other than adenocarcinoma consistent with small cell, ductal, sarcomatoid carcinoma of the prostate
Unable or unwilling to receive concurrent ADT alongside an ARPI
Any concurrent or previous malignancy that required active anti-cancer therapy in the previous 2 years of randomisation (other than basal cell or squamous cell carcinoma of the skin or adequately treated non-muscle invasive urothelial bladder carcinoma, Tis, Ta and T1 tumours)
Adults with unmanaged psychological, familial, or sociological conditions precluding them from the ability to provide informed consent or hampering compliance with the study follow-up, including continued drug and alcohol dependence
Trial design
Parallel
Treatments tested in this trial
Abiraterone, Apalutamide, Enzalutamide or Darolutamide (ARPI therapy) (per standard of care) therapy
DrugARPI therapy (Abiraterone, Apalutamide, Enzalutamide or Darolutamide) selected by local investigator per standard of care
Treatment groups
Trial outcomes
Primary outcomes
Overall survival (primary efficacy)
Overall survival, defined as the time from date of randomisation to date of death from any cause, and those who are alive are censored at the date last known to be alive. This will be assessed for non-inferiority using a margin for the absolute risk difference at 2 years of ≤4 percentage points, between reduced and standard dose ARPI arms. A hierarchical approach will be applied to all 3 primary outcome measures, in which each analysis (in turn) should yield a p-value of \<0.05 in the following ranked order: 1. Non-inferiority for overall survival 2. Superiority of a mean difference in QoL fatigue score (expected to be ≥7 units) 3. Superiority for the percentage of patients who do not discontinue ARPI due to adverse events
The percentage of patients who permanently discontinue ARPI due to adverse events
Adverse events will be analysed using CTCAE Version 6.0 categorisation (all grades) for patients who permanently discontinue APRI. A hierarchical approach will be applied to all 3 primary outcome measures, in which each analysis (in turn) should yield a p-value of \<0.05 in the following ranked order: 1. Non-inferiority for overall survival 2. Superiority of a mean difference in QoL fatigue score (expected to be ≥7 units) 3. Superiority for the percentage of patients who do not discontinue ARPI due to adverse events
Fatigue assessed using the EORTC 12-point fatigue scale (primary toxicity)
Fatigue assessed using the EORTC 12-point fatigue scale (QLQ-FA12). A hierarchical approach will be applied to all 3 primary outcome measures, in which each analysis (in turn) should yield a p-value of \<0.05 in the following ranked order: 1. Non-inferiority for overall survival 2. Superiority of a mean difference in QoL fatigue score (expected to be ≥7 units) 3. Superiority for the percentage of patients who do not discontinue ARPI due to adverse events
Secondary outcomes
Toxicities using the CTCAE v6 categorisation (all grades).
Toxicities using the CTCAE Version 6.0 categorisation (all grades). Events that would be of special interest include hypertension, rash, hot flushes, cardiovascular events, and falls.
Failure-free survival (FFS)
Failure-free survival (FFS) defined as the time from the date of randomisation to the date of the first of the following forms of treatment failure: biochemical (prostate-specific antigen (PSA)) failure; progression of local, lymph-node, or distant metastases; starting another line of therapy, or death from prostate cancer. Patients without an FFS event would be censored at the date last known to be alive. Stopping treatment for reasons other than the events listed above would not be considered an FFS event.
Measures of progression (rising PSA, and locally defined clinical and radiological progression), at 1 and 2 years post-randomisation.
* Proportion of patients who have rising PSA (PSA progression is defined as ≥25% increase and at least a 2 ng/mL absolute increase above the nadir, confirmed by a second value ≥3 weeks later) at 1 and 2 years post randomisation. * Proportion of patients who have PSA only progression: PSA rise of ≥25% above lowest PSA result compared to baseline at 1 and 2 years post randomisation. * Proportion of patients who have significant clinical progression, including new cancer related symptoms, as determined by the local clinical team: at 1 and 2 years post randomisation. * Proportion of patients who have radiological progression as determined by the local clinical team: at 1 and 2 years post randomisation. * Proportion of patients who achieve PSA nadir of \<0.2 within 12 months of starting therapy (primarily for mHSPC patients).
Adherence: the proportion of patients who stop ARPI permanently due to reasons other than disease progression, at 1 and 2 years.
Adherence: proportion of patients who stop ARPI permanently due to reasons other than disease progression, at 1 and 2 years (reasons will be recorded).
Sponsors and contacts
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University College, London
Lead sponsor
Cancer Research UK
Collaborator
Prostate Cancer UK
Collaborator
University of Manchester
Collaborator