NCT07005154 · Astellas Pharma Global Development, Inc.
A Phase 2 Study to Evaluate the Effects of ASP5541 in Participants With Prostate Cancer
What this study is about
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.
View original scientific description
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.
Interventions
DRUG
ASP5541
Intramuscular Injection
DRUG
Prednisone
Oral
DRUG
Prednisolone
Oral
DRUG
abiraterone acetate
Oral
DRUG
Adrenocorticotropic hormone
Intramuscular or intravenous injection
Primary outcome measures
Proportion of androgen receptor pathway inhibitor (ARPI) -naïve metastatic castration-resistant prostate cancer (mCRPC) participants with Prostate Specific Antigen (PSA) decline ≥ 90% (Cohort 1)
Time frame: Up to 37 months
PSA will be recorded from blood sample.
Rate of no mineralocorticoid toxicity (Cohort 2 Group A, Safety run-in)
Time frame: Up to 37 months
No mineralocorticoid toxicity is defined as experiencing neither Grade ≥ 1 hypokalemia nor Grade ≥ 2 hypertension.
Proportion of metastatic hormone-sensitive prostate cancer (mHSPC) participants with prostate-specific antigen (PSA) ≤ 0.2 ng/mL (Cohort 2)
Time frame: At 8 months
PSA will be recorded from blood sample.
Dose-limiting toxicities (DLTs) (Cohort 3)
Time frame: Up to Day 28
A DLT is defined as any event meeting the DLT criteria occurring during the first 28 days of treatment regardless of attribution to the study drug unless it is clearly related to disease progress or intercurrent illness.
Number of participants with Adverse Events (AEs) (Cohort 3)
Time frame: Up to 39 months
AEs will be coded using MedDRA. An AE is any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.
Number of Participants With Serious Adverse Events (SAEs) (Cohort 3)
Time frame: Up to 39 months
An SAE is defined as any untoward medical occurrence that, at any dose: Results in death, is life-threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, is congenital anomaly/birth defect or other situations.
Number of participants with laboratory value abnormalities and/or AEs (Cohort 3)
Time frame: Up to 37 months
Number of participants with potentially clinically significant laboratory values.
Number of participants with electrocardiogram (ECG) abnormalities and/or AEs (Cohort 3)
Time frame: Up to 36 months
Number of participants with potentially clinically significant ECG values.
Number of participants with vital sign abnormalities and/or AEs (Cohort 3)
Time frame: Up to 37 months
Number of participants with potentially clinically significant vital sign values.
Number of participants with physical exam abnormalities and/or AEs (Cohort 3)
Time frame: Up to 36 months
Number of participants with potentially clinically significant physical exam values.
Eastern Cooperative Oncology Group (ECOG) Performance Status (Cohort 3)
Time frame: Up to 36 months
The ECOG scale will be used to assess performance status. Grades range from 0 (fully active) to 5 (dead). Negative change scores indicate an improvement. Positive scores indicate a decline in performance.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- 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 with mHSPC must have an estimated life expectancy of ≥ 12 months or \> 6 months if participant has mCRPC.
- Participant is able to understand and comply with all study requirements and procedures, including completion of PRO questionnaires.
- Male participant must agree to use defined forms of contraception with female partner(s) of childbearing potential (including breastfeeding partner) throughout the treatment period and for 7 months after final ASP5541 or for 3 months after AA study intervention 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
Where
- Huntsville, Alabama
- San Diego, California
- Tampa, Florida
- Chicago Ridge, Illinois
- Evanston, Illinois
- New Orleans, Louisiana
- Albuquerque, New Mexico
- Cincinnati, Ohio
- Myrtle Beach, South Carolina
- Nashville, Tennessee
- Charlottesville, Virginia
- Madison, Wisconsin
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jul 15, 2026 · Source of record for eligibility and locations