A Phase 2 Study to Evaluate the Effects of ASP5541 in Participants With Prostate Cancer

Recruiting now · Phase 2

Conditions studied: Prostate Cancer, Metastatic Castration-Resistant Prostate Cancer, Metastatic Hormone Sensitive Prostate Cancer

In brief

Hormone therapy, or androgen deprivation therapy (ADT) is a standard way to treat prostate cancer. It works by reducing the amount of the main male sex hormone, testosterone in the body. Androgen receptor pathway inhibitors (ARPIs) are another type of hormone therapy. They either slow down how much testosterone is made or block testosterone from reaching the prostate cancer cells. Abiraterone acetate (AA) is an ARPI that is used to treat advanced prostate cancer. This type of treatment is usually given as a tablet with a steroid called prednisone/prednisolone to manage any medical problems from the hormone therapy. ASP5541 is a different form of abiraterone acetate. It is given as an injection into the muscle. In this study, ASP5541 will be given to men with advanced prostate cancer, both with and without prednisone/prednisolone. This study will check the safety of ASP5541 and compare how well ASP5541 works in men with advanced prostate cancer compared to abiraterone acetate. The main aims of the study are: * To check how well ASP5541 with prednisone/prednisolone works compared to AA with prednisone/prednisolone in men with advanced prostate cancer who haven't previously been treated with an ARPI. * To check the safety of ASP5541 given by itself in men with advanced prostate cancer that haven't previously been treated with an ARPI. * To check how well ASP5541 given by itself works compared to AA with prednisone/prednisolone in men with advanced prostate cancer that haven't previously been treated with an ARPI. * To check the safety of ASP5541 with prednisone/prednisolone in Japanese men with advanced prostate cancer. Adult men with a certain type of advanced prostate cancer can take part. Their cancer has spread to other parts of the body (metastatic). The different types are: * Metastatic hormone-sensitive prostate cancer (mHSPC). Prostate cancer that needs testosterone to grow. * Metastatic castration-resistant prostate cancer (mCRPC). Prostate cancer that continues to grow even when testosterone levels are low. In this study there will be 3 treatment groups: * In Group 1, men with mCRPC who haven't previously been treated with an androgen receptor pathway inhibitor will either be given ASP5541 and prednisone/prednisolone or be given abiraterone acetate and prednisone/prednisolone. * In Group 2, men with mHSPC who haven't previously been treated with an androgen receptor pathway inhibitor will either be given ASP5541 by itself or be given abiraterone acetate with prednisone/prednisolone. * In Group 3, Japanese men with mCRPC or mHSPC who may or may not have previously been treated with an androgen receptor pathway inhibitor will be given ASP5541 with prednisone/prednisolone. ASP5541 will be given as an injection into a muscle every 12 weeks. Men with mCRPC will take prednisone/prednisolone twice daily and men with mHSPC will take prednisone/prednisolone once daily. Abiraterone acetate will be given as tablets to be taken once daily. All groups will also receive the standard of care treatment, such as androgen deprivation therapy. The men in the study will visit their clinic regularly during and after treatment for health checks, including checking for any medical problems. Some men (Group 2) will check their blood pressure weekly at home. On some visits they will also have scans to check for any changes in their cancer. The number of visits and type of safety checks done at each visit will depend on the health of each person and when they completed their treatment.

Key facts

Study ID: NCT07005154
Run by: Astellas Pharma Global Development, Inc.
People needed: 218
Starts: 2025-06-19
Expected to finish: 2032-05-31
Last updated by the study team: 2026-07-31

Who can join

Age: 18 and older. Sex: male. Healthy volunteers: not accepted.

You may qualify if…

Participant is diagnosed with histologically or cytologically confirmed adenocarcinoma of the prostate without neuroendocrine differentiation or small cell features.
Participant has ECOG performance status of 0 or 1, or ECOG performance status of 2 if due to bone pain.
Participant must have an estimated life expectancy of ≥ 12 months with mHSPC or ≥ 6 months with mCRPC.
Participant is able to understand and comply with all study requirements and procedures.
Participant has been diagnosed with mCRPC or mHSPC documented by metastatic lesions on a bone scan, computed tomography (CT), magnetic resonance imaging (MRI) or prostate-specific membrane antigen positron emission tomography (PSMA-PET).
Participant is receiving ongoing ADT with a gonadotropin-releasing hormone (GnRH) analogue or has a history of bilateral orchiectomy (i.e., surgical or medical castration). Participant with mHSPC must have started castration therapy (medical or surgical) at least 14 days prior to Cycle 1 Day 1 (C1D1).
Note: Participant who has not had a bilateral orchiectomy must have a plan to maintain effective GnRH analogue therapy for the duration of the study.
If the participant has mCRPC, participant has evidence of disease progression defined as 1 or more of the following criteria at study entry:
Evidence of radiographic progression of disease prior to first dose and following the most recent prostate cancer treatment, defined as progressive disease on CT/MRI per Response Evaluation Criteria in Solid Tumours (RECIST) v1.1 or on a bone scan per PCWG3.
PSA progression defined as an increase in PSA of at least 25% and ≥ 1 ng/mL above the nadir, confirmed by a second value 1 week later, and with at least 1 of the measurements within 90 days prior to screening. PSA nadir is defined as the lowest PSA during or after the most recent treatment.
If the participant has mCRPC, participant has a serum testosterone level < 1.73 nmol/L (< 50 ng/dL) at the Screening visit.
Male participant must agree to use contraception with female partner(s) of childbearing potential (including breastfeeding partner) throughout the treatment period and for 7 months after final ASP5541 administration.
Male participant must agree to remain abstinent or use a condom with pregnant partner(s) for the duration of the pregnancy throughout the investigational period and for 7 months after final ASP5541 administration.
Male participant must not donate sperm during the treatment period and for 7 months after final ASP5541 administration.
Participant agrees not to participate in another interventional study while receiving ASP5541 in the present study.
Participant should have normal serum potassium (within the local laboratory normal range) at screening without supplementation.

You may not qualify if…

Participant has any concurrent disease, infection or comorbid condition that interferes with the ability of the subject to participate in the study, which places the subject at undue risk or complicates the interpretation of data.
Participant has known active central nervous system (CNS) metastases. Note: Participant with CNS metastases who has been treated with surgery and/or radiation therapy, who is off pharmacologic doses of glucocorticoids and who is neurologically stable is eligible.
Participant has a known additional malignancy beyond prostate cancer that requires active treatment with the exception of any of the following:
Adequately treated basal cell carcinoma, squamous cell carcinoma of the skin, or in situ carcinoma of any type
Adequately treated Stage I cancer from which the participant is currently in remission and has been in remission for ≥ 2 years
Any other cancer from which the participant has been disease-free for ≥5 years
Participant has clinically significant cardiac disease, defined as any of the following:
Clinically significant cardiac arrhythmias including bradyarrhythmia which are poorly controlled. Rate-controlled atrial fibrillation is permitted.
Congenital long QT syndrome.
QT interval corrected by Fridericia's formula (QTcF) ≥450 msec at Screening. If the QT interval corrected for heart rate intervals (QTc) is prolonged in a participant with a pacemaker or bundle branch block, the participant may be enrolled in the study if confirmed by the medical monitor.
History of clinically significant cardiac disease or congestive heart failure greater than New York Heart Association (NYHA) Class II or left ventricular ejection fraction measurement of < 50% at baseline.
Cohorts 1 and 3: Participant must not have unstable angina (symptoms at rest) or new-onset angina within the last 3 months or myocardial infarction within the past 6 months.
Cohort 2: Participants must not have symptomatic heart failure, unstable or new-onset angina or myocardial infarction within the past 12 months.
Cohorts 1 and 3: Uncontrolled hypertension, defined as systolic blood pressure > 160 mmHg or diastolic blood pressure > 100 mmHg that has been confirmed by 2 successive measurements despite optimal medical management.
Cohort 2: Uncontrolled hypertension, defined as systolic BP > 140 mmHg or diastolic BP > 90 mmHg that has been confirmed by 2 successive measurements despite optimal medical management. Participants may be receiving a maximum of 2 antihypertensives that were initiated at least 3 months prior to Cycle 1 Day 1.
Cohort 1 and 3: Arterial or venous thrombotic or embolic events such as cerebrovascular accident (including transient ischemic attacks), deep vein thrombosis, or pulmonary embolism within the 3 months before start of study medication (except for adequately treated catheter related venous thrombosis occurring > 1 month before Cycle 1 Day 1).
Cohort 2: Arterial thrombotic or embolic events such as cerebrovascular accident (including transient ischemic attacks) within the last 12 months.
Participant has any unresolved National Cancer Institute-Common Terminology Criteria for Adverse Events (NCI-CTCAE) (version 5.0) Grade > 2 toxicity at the Screening visit. Note: Participant receiving ongoing hormone replacement therapy for endocrine immune-related AEs without clinical symptoms will not be excluded.
Participant has had major surgery (e.g., requiring general anesthesia) within 30 days before screening, or has not fully recovered from surgery, or has major surgery planned during the time the participant is expected to participate in the study.
Participant has/had febrile illness or symptomatic, viral, bacterial (including upper respiratory infection) or fungal (noncutaneous) infection within 28 days prior to day 1.
Participant received a blood transfusion within 1 month of the first dose of study intervention.
Participant has a history of impaired pituitary or adrenal gland function (e.g., Addison's disease, Cushing's syndrome).
Participant has hemoglobin A1c (HbA1c) > 10% (if diabetes mellitus was previously diagnosed) or HbA1c > 8% (if diabetes mellitus was previously undiagnosed). (Excluded participant may be rescreened after referral and evidence of improved control of their condition.)
Participant has jaundice or known current active liver disease from any cause, including hepatitis A (hepatitis A virus IgM positive, but testing for hepatitis A in screening is not required), hepatitis B (hepatitis B virus surface antigen positive, confirmed by hepatitis B virus DNA), or hepatitis C (hepatitis C virus antibody positive, confirmed by hepatitis C virus RNA).
Participant has moderate or severe hepatic impairment (Child-Pugh Class B or C).

Where it is running

Sharp HealthCare - Sharp Memorial Hospital — San Diego, California, United States (enrolling)
H. Lee Moffitt Cancer Center — Tampa, Florida, United States (enrolling)
Associated Urological Specialists — Chicago Ridge, Illinois, United States (enrolling)
NorthShore University HealthSystem — Evanston, Illinois, United States (enrolling)
Ochsner Health - Ochsner Medical Center - New Orleans — New Orleans, Louisiana, United States (enrolling)
New Mexico Oncology Hematology Consultants — Albuquerque, New Mexico, United States (enrolling)
Solaris Health - The Urology Group — Cincinnati, Ohio, United States (enrolling)
Carolina Urologic Research Center — Myrtle Beach, South Carolina, United States (enrolling)
Tennessee Oncology Nashville — Nashville, Tennessee, United States (enrolling)
University of Virginia Cancer Center — Charlottesville, Virginia, United States (enrolling)
UW Health Carbone Cancer Center — Madison, Wisconsin, United States (enrolling)
Subei People's Hospital — Yangzhou, Jiangsu, China (enrolling)
The Second Hospital of Tianjin Medical University — Tianjin, Tianjin Municipality, China (enrolling)
The First Affiliated Hospital, Zhejiang University School of Medicine — Hangzhou, Zhejiang, China (enrolling)
Huai'an First People's Hospital — Huaian, China (enrolling)
Renji Hospital Shanghai Jiaotong Univ School of Medicine — Shanghai, China (enrolling)
Site FR33003 — Bordeaux, France (enrolling)
Site FR33009 — Le Mans, France (enrolling)
Site FR33008 — Lille, France (enrolling)
Site FR33006 — Paris, France (enrolling)
Site FR33004 — Strasbourg, France (enrolling)
Site DE49004 — Nürtingen, Baden-Wurttemberg, Germany (enrolling)
Site DE49001 — Heinsberg, Germany (enrolling)
Site IT39004 — Milan, Italy (enrolling)
Clearview Cancer Institute — Huntsville, Alabama, United States (enrolling)

Full record on ClinicalTrials.gov

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