A Study Testing if Patients With Advanced Prostate Cancer Who Are Responding Well to Combination Treatment Can Safely Reduce Their Medication to a Single Hormone Therapy, Compared to Continuing Their Current Drugs

Trial statusNot yet recruiting
Trial phasePhase 2
Trial typeInterventional
Biological sexMale
Age18-80
SponsorKokilaben Dhirubhai Ambani Hospital and Medical Research Institute

About this trial

The goal of this randomized comparative study (a study where participants are placed into groups by chance) is to find out if reducing treatment to androgen deprivation therapy (ADT)-a treatment that lowers testosterone-by itself works just as well as continuing the original combination of drugs. This study involves adult men with metastatic hormone-sensitive prostate cancer (prostate cancer that has spread to other parts of the body but still responds to hormone treatments) who have responded very well after 6 to 7 months of their initial two-drug or three-drug treatment.

The main questions it aims to answer are:

1. Does reducing treatment to ADT alone work as well as the combination treatment at keeping the cancer from growing on imaging scans after 18 months, also known as radiographic progression-free survival (rPFS)? 2. Does reducing treatment to ADT alone work as well as the combination treatment at preventing a rise in prostate-specific antigen (PSA), known as PSA progression-free survival (PSA-PFS)?

Researchers will compare a continuation group, which continues their initial two-drug or three-drug treatment, to a reduced-treatment group, which stops taking the androgen receptor pathway inhibitor (ARPI)-a drug that blocks the effects of hormones on cancer cells. Researchers want to see if reducing the treatment safely controls the cancer while lowering drug side effects and financial costs.

Participants will:

1. Complete a 6- to 7-month initial period receiving a two-drug or three-drug treatment chosen by their doctor. 2. Have blood tests for PSA and testosterone, and undergo a specialized imaging scan called a prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) scan, to confirm the treatment is working very well before being assigned to a study group. 3. Stop taking the ARPI drug if assigned to the reduced-treatment group, or continue their current medications if assigned to the continuation group. 4. Go to check-up visits every 3 months for the first 24 months to complete physical exams, blood tests, and quality-of-life surveys. 5. Have a PSMA PET/CT scan every 6 months after being put into a group to check if the cancer has grown.

Eligibility criteria

This trial does not accept healthy volunteers

Qualifiers

All patients of age group 18 to 80 years will be included

Patients who would voluntarily agree to sign informed consent form

Histologically confirmed adenocarcinoma of the prostate

Evidence of metastatic disease at diagnosis (de novo) or after definitive local therapy, documented on PSMA PET/CT

Disqualifiers

Known small-cell, neuroendocrine or predominantly sarcomatoid histology

Prior systemic therapy for prostate cancer other than ≤ 90 days of ADT (± a short course of first-generation anti-androgen for flare prevention) at enrolment

Prior treatment with any ARPI, docetaxel, cabazitaxel, Ra-223 or 177Lu-PSMA

Uncontrolled hypertension (systolic ≥ 160 mm Hg or diastolic ≥ 100 mm Hg despite therapy), history of seizures or predisposing conditions (for enzalutamide candidates), unstable cardiac disease, recent myocardial infarction or stroke within 6 months

Trial design

Design model

Parallel

Treatments tested in this trial

  • De-escalation strategy

    Other intervention

    The experimental intervention is a response-adapted de-escalation to Androgen Deprivation Therapy (ADT) monotherapy, achieved by completely discontinuing Androgen Receptor Pathway Inhibitor (ARPI) treatment (and associated corticosteroids). This de-escalation is initiated only after patients complete a 6-to-7-month run-in phase of standard doublet or triplet therapy.

  • Continuation of initial Androgen Deprivation Therapy (ADT) and Androgen Receptor Pathway Inhibitor (ARPI) combination therapy at standard doses

    Drug

    Arm-A serves as the standard-of-care control arm, in which patients continue their intensified combination therapy despite having achieved a deep clinical and molecular response. The intervention strictly involves continuing the identical Androgen Deprivation Therapy (ADT) and Androgen Receptor Pathway Inhibitor (ARPI) regimen-such as abiraterone, enzalutamide, apalutamide, or darolutamide-administered during the 6-to-7-month run-in phase, maintained at original doses.

Treatment groups

170 Participants
are divided into 2 treatment groups
Group A: Arm A - ContinuationActive comparator 1 intervention
Group B: Arm B - De-escalationExperimental treatment 1 intervention

Trial outcomes

Primary outcomes

1

18-month radiographic progression-free survival (rPFS)

Time from randomization to the earliest of: radiographic progression per PCWG4 on PSMA PET; unequivocal progression on PSMA PET (≥ 2 new lesions or PPP progression); or death from any cause. Patients without an event at 18 months are censored at last assessment.

Time frame
Assessed from the date of randomization up to 18 months, with routine PSMA PET/CT imaging conducted every 6 months (patients without an event at 18 months are censored at their last assessment)
2

PSA progression-free survival

Time from randomization to confirmed PSA progression per PCWG4 (≥ 25 % rise and ≥ 2 ng/mL above nadir, confirmed ≥ 3 weeks later), or death

Time frame
Assessed from the time of randomization until confirmed PSA progression or death, evaluated every 3 months for the first 24 months and every 6 months thereafter, through the total follow-up period (minimum 24 months post-randomization; up to 60 months)

Secondary outcomes

1

Time to CRPC

Time from randomization to castration resistance per EAU/PCWG4 definition

Time frame
Through study completion, an average of 5 years
2

Overall survival

Time from randomization to death from any cause

Time frame
Assessed continuously from the date of randomization until death from any cause, with survival follow-up conducted every 6 months until study conclusion (up to approximately 60 months total duration)
3

PSMA PET complete response

Proportion with sustained PSMA PET complete response per modified PPP/RECIP at 12 and 24 months

Time frame
From randomization, at 12 and 24 months
4

Change in Quality of Life Measured by the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30)

Change from baseline in health-related quality of life assessed using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30). The EORTC QLQ-C30 includes a Global Health Status/Quality of Life (GHS/QoL) scale, functional scales, and symptom scales/items. All scales and single items range from 0 to 100. For the Global Health Status and functional scales, a higher score represents a higher/better level of functioning and quality of life. For symptom scales and items, a higher score represents a higher/worse level of symptoms or problems.

Time frame
Assessed via changes from baseline, measured at screening, at the 6-7 month re-staging/randomization visit, and every 3 months post-randomization for the first 24 months

Other outcomes

1

Biomarker-outcome associations

Baseline and on-treatment PSMA PET metrics

Time frame
PSMA PET metrics, are assessed at baseline, at the 6-to-7-month re-staging visit, every 6 months post-randomization up to 60 months

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