Apa/Enza-short Study: Shorter Treatment With Androgen Receptor Pathway Inhibitor in Patients With Low-volume Metastatic Castration-sensitive Prostate Cancer (Apa/Enza-short)

December 2, 2025 updated by: Nick Beije

Apa/Enza Short Study: Shortened 12 Months Duration of Androgen Receptor Signaling Agent in Combination With Androgen Deprivation Therapy in Patients With Low Volume Castration-sensitive Prostate Cancer: a Randomized Nationwide Study

The goal of this clinical trial is to evaluate the outcomes of a shorter treatment duration (12 months) with an androgen receptor pathway inhibitor (ARPI), in this study Apalutamide or Enzalutamide, in patients with low-volume, hormone-sensitive metastatic prostate cancer (mCSPC), with the possibility to restart treatment if needed.

The main research question is whether discontinuation of ARPI therapy after 12 months, with the option to restart treatment upon disease progression, is non-inferior to continued ARPI therapy, potentially reducing toxicity and costs.

Eligible patients will be randomized after completing 12 months of ARPI treatment, to one of the following two arms:

  1. ADT + continued ARPI (Apalutamide or Enzalutamide)
  2. ADT + ARPI discontinued after 12 months, with the option to resume ARPI in case of a confirmed PSA rise. The confirmatory PSA sample must be obtained at least 4 weeks after the initial rise.

This study aims to minimize toxicity associated with prolonged use of ARPIs in patients with low-volume, hormone-sensitive metastatic prostate cancer.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

400

Phase

  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Netherlands
      • Alkmaar, Netherlands
        • Recruiting
        • Noordwest Ziekenhuisgroep
        • Contact:
      • Amersfoort, Netherlands
        • Not yet recruiting
        • Meander MC Amersfoort
        • Contact:
      • Amsterdam, Netherlands
        • Not yet recruiting
        • Antoni van Leeuwenhoek
        • Contact:
      • Amsterdam, Netherlands
        • Not yet recruiting
        • Amsterdam Universitair Medisch Centrum
        • Contact:
      • Assen, Netherlands
        • Recruiting
        • Wilhelmina Ziekenhuis Assen
        • Contact:
      • Beverwijk, Netherlands
        • Recruiting
        • Rode Kruis Ziekenhuis
        • Contact:
      • Deventer, Netherlands
        • Recruiting
        • Deventer Ziekenhuis
        • Contact:
      • Eindhoven, Netherlands
      • Emmen, Netherlands
        • Recruiting
        • Treant Zorggroep
        • Contact:
      • Enschede, Netherlands
        • Recruiting
        • Medisch Spectrum Twente
        • Contact:
      • Goes, Netherlands
        • Recruiting
        • Admiraal De Ruyter Ziekenhuis
        • Contact:
      • Groningen, Netherlands
        • Recruiting
        • Universitair Medisch Centrum Groningen
        • Contact:
      • Haarlem, Netherlands
      • Hengelo, Netherlands
        • Recruiting
        • Ziekenhuisgroep Twente
        • Contact:
      • Hilversum, Netherlands
        • Not yet recruiting
        • Tergooi Mc
        • Contact:
      • Leeuwarden, Netherlands
        • Recruiting
        • Frisius MC Leeuwarden
        • Contact:
      • Maastricht, Netherlands
        • Recruiting
        • Maastricht UMC
        • Contact:
      • Nijmegen, Netherlands
        • Recruiting
        • Canisius Wilhelmina Ziekenhuis
        • Contact:
      • Roermond, Netherlands
        • Recruiting
        • Laurentius Ziekenhuis
        • Contact:
      • Roosendaal, Netherlands
        • Recruiting
        • Bravis ziekenhuis
        • Contact:
      • Rotterdam, Netherlands
      • Rotterdam, Netherlands
      • Rotterdam, Netherlands
        • Recruiting
        • Fransicus Gasthuis & Vlietland
        • Contact:
      • The Hague, Netherlands
      • Utrecht, Netherlands
      • Venlo, Netherlands
        • Recruiting
        • VieCuri Medisch Centrum
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Male and ≥18 years of age
  • Capable of understanding and complying with protocol requirements and able to understand and sign the informed consent form
  • Histological diagnosis of prostate adenocarcinoma
  • Low volume de novo metastatic disease (M1a or M1b) defined as anything other than fitting the criteria for high-volume metastatic disease, e.g., four or more bone lesions with one or more lesions in any body structure beyond the spine or pelvis, or visceral disease (non-nodal). This has been assessed by either bone scan and computed tomography (CT), or PSMA-PET scan. Low-volume disease has subsequently been confirmed by the local (multidisciplinary) team after consideration of the available imaging results as per the standard imaging protocol for the site.
  • ADT initiated within 6 weeks prior to inclusion
  • Eastern Cooperative Oncology Group (ECOG) performance scale status of 0, 1 or 2
  • Fit for treatment with apalutamide or enzalutamide according to treating physician

Exclusion Criteria:

  • Pathological finding consistent with small cell, ductal or neuroendocrine carcinoma of the prostate
  • Other prior malignancy less than or equal to 5 years prior to randomization except for squamous or basal cell skin carcinoma or non-invasive superficial bladder cancer
  • History of seizures or medications known to lower seizure threshold
  • Any other prior treatment for prostate cancer other than ADT (e.g., other next generation anti-androgens or other CYP17 inhibitors, chemotherapy, immunotherapy, or radiopharmaceutical agents)
  • ADT started more than 6 weeks before inclusion

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Supportive Care
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: ADT plus continued ARPI (apalutamide/enzalutamide)
Drug: ADT plus continued ARPI
ADT plus continued ARPI (apalutamide/enzalutamide) to the moment of progression
Experimental: ADT plus only 12 months of ARPI (apalutamide/enzalutamide) with the possibility t
Drug: ADT plus only 12 months of ARPI
ADT plus only 12 months of ARPI (apalutamide/enzalutamide) with the possibility to resume treatment with ARSI in case of a confirmed PSA rise.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Time to clinical progression free survival (cPFS) in both arms.
Time Frame: From inclusion to the last day of treatment or moment of progression (whichever occurs first). Subjects will participate for 5 years, after randomization. In total, patients will participate for 6 years.
To prospectively evaluate whether shortened (12 months) treatment with ARPIs, with retreatment with ARPIs in case of PSA progression (defined according to PSA progression criteria) is non-inferior with respect to clinical progression free survival (boundary of max -10% at 48 months) to continued treatment with ARPI evaluated by comparing time to cPFS (as defined in primary endpoint) in both arms.
From inclusion to the last day of treatment or moment of progression (whichever occurs first). Subjects will participate for 5 years, after randomization. In total, patients will participate for 6 years.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Nick Beije

Collaborators

Stichting Treatmeds

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

February 20, 2024

Primary Completion (Estimated)

November 30, 2027

Study Completion (Estimated)

December 1, 2027

Study Registration Dates

First Submitted

November 21, 2025

First Submitted That Met QC Criteria

December 2, 2025

First Posted (Estimated)

December 3, 2025

Study Record Updates

Last Update Posted (Estimated)

December 3, 2025

Last Update Submitted That Met QC Criteria

December 2, 2025

Last Verified

December 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • EU CT 2023-506698-36

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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