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Prostate CancerPhase 1NCT07339267

A Study to Evaluate the Safety and Drug Levels of ASP5541 in Chinese Participants With Prostate Cancer

A Phase 1 study testing ASP5541 and Prednisone in people with Prostate Cancer and Metastatic Castration-Resistant Prostate Cancer, run by Astellas Pharma Global Development, Inc. at 1 site in China.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
Search all trials

Trial summary

In this study, ASP5541 will be given to Chinese men with prostate cancer. It will be given together with prednisone and androgen deprivation therapy (ADT). Prednisone is a steroid, and ADT is already given to the men as their standard of care for prostate cancer. Read more about this study

Who is it for?
Ages 18 to 85 years, men only
What is being tested?
ASP5541 and Prednisone
Could I receive a placebo?
No, everyone receives an active treatment
How many people
12 participants
Where
1 siteChina
Study dates
20 Jan 2026to 31 Oct 2028
Phase
Phase 1
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 to 85 years
  • Men only
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Participant is diagnosed with histologically or cytologically confirmed adenocarcinoma of the prostate without neuroendocrine differentiation or small cell features.
  • Participant has Eastern Cooperative Oncology Group (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 metastatic hormone-sensitive prostate cancer (mHSPC) or ≥ 6 months with metastatic castration-resistant prostate cancer (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 androgen deprivation therapy (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).
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  • 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 has adequate ventrogluteal muscle mass for an intramuscular injection.
  • Participant agrees not to participate in another interventional study while receiving ASP5541 in the present study.

Who cannot join

  • 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
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  • 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. 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.
  • 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.
  • 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 the start of study medication).
  • 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 90 days before screening, or will not have 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).
  • Participant has a known history of human immunodeficiency virus (HIV) infection (HIV antibody positive).
  • Participant has a body mass index > 40 kg/m2.
  • Participant has a history of drug or alcohol abuse according to Diagnostic and Statistical Manual of Mental Disorders, 5th edition criteria within 2 years before screening.
  • Participant received treatment with glucocorticoids greater than the equivalent of 10 mg per day of prednisone within 4 weeks prior to C1D1. The use of topical, intraocular, inhalational, intranasal or intra-articular glucocorticoids is permitted.
  • Participant received treatment with Chinese traditional medications with known antitumor activity or herbal products within 4 weeks prior to C1D1 (e.g., saw palmetto). Participant must agree not to use such Chinese traditional medications or herbal products during study participation.
  • Participant is receiving current treatment with systemic ketoconazole, abiraterone acetate (AA) or any other cytochrome P450 17A1 (CYP17) inhibitor. Participant who has received systemic ketoconazole, AA or any other CYP17 inhibitor must have discontinued these agents ≥ 4 weeks prior to the first dose of study intervention.
  • Participant received prior systemic treatment with a strong inducer or inhibitor of cytochrome p450 3A4 (CYP3A4) within 4 weeks of first dose of study intervention. Concomitant use of strong inducers or inhibitors of CYP3A4 are not permitted on study.
  • Participant requires use of biotin (i.e., vitamin B7) or supplements containing biotin higher than the daily adequate intake of 30 μg. Note: Participant who switches from a high dose to a dose of 30 μg/day or less prior to first dose of study drug is eligible for study entry.
  • Participant is required to use any prohibited medication on the List of Excluded Concomitant Medications.
  • For mCRPC participants only: Participant has been treated with any of the following for prostate cancer, during the indicated time frame prior to enrollment:
  • Hormonal therapy (e.g., androgen receptor blockers [AR] antagonists, second-generation androgen receptor pathway inhibitors [including enzalutamide, apalutamide, darolutamide, rezvilutamide and AA], 5-alpha reductase inhibitors, estrogens, cyproterone acetate) within 4 weeks of C1D1. Note: Participant has been treated with bicalutamide within 6 weeks prior to enrollment is not permitted. Participant has been treated with all other GnRH analogues or antagonists is permitted.
  • Chemotherapy within 2 weeks or 5 half-lives of C1D1 (whichever is longer)
  • Biologic therapy within 4 weeks of C1D1
  • Immunotherapy within 4 weeks of C1D1
  • Radiation therapy (includes radioligands) within 4 weeks of C1D1
  • For mHSPC participants only: Participant has received any prior pharmacotherapy, radiation therapy or surgery for metastatic prostate cancer (the following exceptions are permitted):
  • Up to 4 months of ADT with GnRH agonists or antagonists or orchiectomy (within 3 months prior to C1D1) with or without concurrent antiandrogens.
  • Participant may have 1 course of palliative radiation or surgical therapy to treat symptoms resulting from metastatic disease if it was administered at least 4 weeks prior to C1D1.
  • Up to 6 cycles of docetaxel therapy, with the last dose of docetaxel ≤ 2 months prior to C1D1. A participant who has received docetaxel should have maintained a response to docetaxel of stable disease or better, by imaging and PSA, prior to C1D1.
  • Up to 6 months of ADT with GnRH agonists or antagonists or orchiectomy with or without concurrent antiandrogens prior to C1D1 if subject was treated with docetaxel, with no radiographic evidence of disease progression or rising PSA levels prior to C1D1.
  • Participant has received any investigational therapy within 4 weeks or 5 half-lives (whichever is longer) prior to C1D1.
  • Participant has received ASP5541 previously.
  • Participant has absolute neutrophil count < 1500/μL, platelet count < 100000/μL or hemoglobin < 9 g/dL (6.2 mmol/L) or international normalized ratio (INR) ≥ 1.5 (unless participant is taking oral anticoagulants in which case INR ≤ 2.0 is permitted) at Screening. Note: Participant may not have received any growth factors within 7 days or blood transfusions within 28 days prior to the hematology values obtained at Screening.
  • Participant has serum total bilirubin > 1.5 x upper limit of normal (ULN) (except participants with documented Gilbert's disease), or serum alanine aminotransferase or aspartate aminotransferase > 2.5 x ULN at Screening.
  • Participant does not have adequate renal function defined as a calculated creatinine clearance < 30 mL/min as determined by a validated algorithm for calculating creatinine clearance.
  • Participant has serum albumin < 3.0 g/dL (30 g/L) at Screening.
  • Participant has a known or suspected hypersensitivity to ASP5541, prednisone, or any components of the formulations used.
  • Participant has a gastrointestinal disorder affecting absorption.

Trial locations and contacts

1 site in 1 country. Contact the study team or a site near you to ask about taking part.

Astellas Pharma Global Development, Inc. contact

800-888-7704

Astellas.registration@astellas.com

China1 site, 1 recruiting

  • Beijing Hospital

    Beijing, Beijing Municipality

    Recruiting

Other trials in China

About this study

Official title: A Phase 1, Open-label Study to Evaluate the Pharmacokinetics and Safety of ASP5541 in Chinese Participants With Advanced Prostate Cancer

In this study, ASP5541 will be given to Chinese men with prostate cancer. It will be given together with prednisone and androgen deprivation therapy (ADT). Prednisone is a steroid, and ADT is already given to the men as their standard of care for prostate cancer.

The main aims of the study are to check the safety of ASP5541, when given with prednisone and ADT, and to check how ASP5541 moves through the bodies of Chinese men.

Read more

The men will receive ASP5541 as an injection into a muscle (intramuscular injection) at the side of the hip. They will all receive the same dose of ASP5541. The men will be given prednisone and ADT according to their label.

The men will continue to receive ASP5541 with prednisone and ADT until their cancer gets worse or the doctor decides the men should stop study treatment.

Being tested
ASP5541, Prednisone
Keywords
ASP5541, PRL-02, Pharmacokinetics
Medical subject headings
Prostatic Neoplasms

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • ASP5541Drug

    Also called PRL-02

    Intramuscular injection

  • PrednisoneDrug

    Oral

Study groups in NCT07339267
Study groupRoleWhat they receive
ASP5541ExperimentalParticipants will receive ASP5541 once every 12 weeks and prednisone either once daily (mHSPC) or twice daily (mCRPC).
Receives: Drug: ASP5541; Drug: Prednisone

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Pharmacokinetics (PK) of Abiraterone Decanoate in Plasma: Maximum Concentration (Cmax)

    Cmax will be recorded from the PK plasma samples collected.

    Measured: Up to 6 months

  2. PK of Abiraterone Decanoate in Plasma: Time to Maximum Concentration (Tmax)

    Tmax will be recorded from the PK plasma samples collected.

    Measured: Up to 6 months

  3. PK of Abiraterone Decanoate in Plasma: Area Under the Curve from Time 0 to the Time of the Last Measurable Concentration (AUClast)

    AUClast will be recorded from the PK plasma samples collected.

    Measured: Up to 6 months

  4. PK of Abiraterone Decanoate in Plasma: Area Under the Concentration Time Curve from the Time of Dose Extrapolated to Time Infinity (AUCinf)

    AUCinf will be recorded from the PK plasma samples collected.

    Measured: Up to 6 months

  5. PK of Abiraterone in Plasma: Maximum Concentration (Cmax)

    Cmax will be recorded from the PK plasma samples collected.

    Measured: Up to 6 months

  6. PK of Abiraterone in Plasma: Time to Maximum Concentration (Tmax)

    Tmax will be recorded from the PK plasma samples collected.

    Measured: Up to 6 months

  7. PK of Abiraterone in Plasma: Area Under the Curve from Time 0 to the Time of the Last Measurable Concentration (AUClast)

    AUClast will be recorded from the PK plasma samples collected.

    Measured: Up to 6 months

  8. PK of Abiraterone in Plasma: Area Under the Concentration Time Curve from the Time of Dose Extrapolated to Time Infinity (AUCinf)

    AUCinf will be recorded from the PK plasma samples collected.

    Measured: Up to 6 months

  9. Number of Participants with Adverse Events (AEs)

    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.

    Note: An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of study intervention. This includes events related to the comparator, if applicable, and events related to the (study) procedures.

    Measured: Up to 33 months

  10. Number of Participants with Laboratory Value Abnormalities and/or AEs

    Number of participants with potentially clinically significant laboratory values.

    Measured: Up to 31 months

  11. Number of Participants with Electrocardiogram (ECG) Abnormalities and/or AEs

    Number of participants with potentially clinically significant ECG values.

    Measured: Up to 31 months

  12. Number of Participants with Vital Sign Abnormalities and/or AEs

    Number of participants with potentially clinically significant vital sign values.

    Measured: Up to 31 months

  13. Number of Participants with Physical Exam Abnormalities and/or AEs

    Number of participants with potentially clinically significant physical exam values.

    Measured: Up to 31 months

  14. Number of Participants at Each Grade of Eastern Cooperative Oncology Group (ECOG) Performance Status Score

    The ECOG scale will be used to assess performance status. ECOG grades range from 0 (fully active) to 5 (dead). Negative change scores represent an improvement. Positive scores represent a decline in performance.

    Measured: Up to 31 months

Secondary outcomes (9)

  1. Number of mHSPC Participants with Prostate-specific Antigen (PSA) ≤ 0.2 ng/mL Levels at 8 Months

    PSA will be recorded from blood samples.

    Measured: Month 8

  2. Number of mHSPC Participants with Prostate-specific Antigen (PSA) ≤ 0.2 ng/mL Levels at 12 Months

    PSA will be recorded from blood samples.

    Measured: Month 12

  3. Number of Participants with a PSA decline ≥ 30% from Baseline

    PSA will be recorded from blood samples.

    Measured: Up to 24 months

  4. Number of Participants with a PSA decline ≥ 50% from Baseline

    PSA will be recorded from blood samples.

    Measured: Up to 24 months

  5. Number of Participants with a PSA decline ≥ 90% from Baseline

    PSA will be recorded from blood samples.

    Measured: Up to 24 months

  6. Number of Participants with a PSA Undetectable Rate (≤ 0.2 ng/mL)

    PSA will be recorded from blood samples.

    Measured: Up to 24 months

  7. Time to PSA Progression Per Prostate Cancer Working Group 3 (PCWG3) Criteria

    Time from first dose to time to PSA progression per PCWG3 criteria, which is defined as:

    an increase in PSA greater than 25% and >2 ng/ml above nadir (the lowest PSA value observed at or post baseline), confirmed by progression at 2 timepoints at least 3 weeks apart.

    Measured: Up to 24 months

  8. Number of Participants who experience Testosterone Suppression to ≤ 1 ng/dL or Achieve a ≥ 90% Reduction from Baseline

    Testosterone levels will be recorded from blood samples.

    Measured: Up to 24 months

  9. Mean Testosterone Values

    Testosterone levels will be recorded from blood samples.

    Measured: Up to 24 months

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted14 Jan 2026
  2. Study start20 Jan 2026
  3. Primary completion31 Oct 2028 (estimated)
  4. Study completion31 Oct 2028 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 1
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrolment
12 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07339267
Sponsor's protocol ID
5541-CL-0102
Status last verified
Oct 2026
First submitted
5 Jan 2026
Last updated
26 Oct 2026
Results posted
No
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
No: Access to anonymized individual participant level data will not be provided for this trial. Further details on Astellas' data sharing policy can be found at https://www.clinicaltrials.astellas.com/transparency/.

Questions about this trial

What is this clinical trial studying?

A Phase 1 study testing ASP5541 and Prednisone in people with Prostate Cancer and Metastatic Castration-Resistant Prostate Cancer, run by Astellas Pharma Global Development, Inc. at 1 site in China.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 16 inclusion and 49 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: looking for participants now, as of the sponsor's last update on 26 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in China. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Astellas Pharma Global Development, Inc. (800-888-7704, Astellas.registration@astellas.com), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Pharmacokinetics (PK) of Abiraterone Decanoate in Plasma: Maximum Concentration (Cmax) (time frame: Up to 6 months). The study lists 14 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT07339267.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 26 Oct 2026.

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