ASP5541 for Prostate Cancer

Recruiting at 7 trial locations

Overseen By Astellas Pharma Global Development, Inc.

Age: 18+

Sex: Male

Trial Phase: Phase 2

Sponsor: Astellas Pharma Global Development, Inc.

Must be taking: GnRH analogues

Must not be taking: CYP3A4 inducers, CYP3A4 inhibitors

Disqualifiers: CNS metastases, Active liver disease, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Prior Safety Data This treatment has passed at least one previous human trial

Compensation: Varies

Number of Visits: 12

Duration: Up to 37 months

218 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial evaluates a new form of hormone therapy for men with advanced prostate cancer that has spread. It compares an injectable treatment, ASP5541, to the standard tablet treatment, abiraterone acetate (AA), both with and without the steroid prednisone. The study aims to assess the effectiveness and safety of ASP5541 compared to AA. Men with advanced prostate cancer that continues to grow despite low testosterone levels or requires testosterone for growth are suitable candidates for the trial. As a Phase 2 trial, the research focuses on measuring the treatment's effectiveness in an initial, smaller group of participants.

Will I have to stop taking my current medications?

The trial requires participants to stop certain medications before starting, such as herbal medications, systemic ketoconazole, and CYP3A4 inducers or inhibitors. You should discuss your current medications with the study team to see if any need to be stopped.

Is there any evidence suggesting that this trial's treatments are likely to be safe?

Research shows that ASP5541 is being carefully studied for its safety in treating prostate cancer. This treatment is a new form of abiraterone acetate (AA), already used for advanced prostate cancer. Unlike the usual AA tablets, ASP5541 is administered as an injection.

In earlier safety studies, researchers tested ASP5541 in men whose cancer continued to grow despite previous treatments. These studies help determine how well people tolerate the treatment and what side effects might occur. Although specific side effects weren't detailed, the fact that this is a Phase 2 trial indicates ASP5541 has shown sufficient safety in earlier tests to warrant further research.

For those considering joining a clinical trial, ASP5541 has been tested in smaller groups and is now being tested in more people to gather additional safety information. This is a positive sign, but like all clinical trials, there may still be unknowns. Discuss any concerns with a healthcare provider. ^{1 2 3 4 5}

Why are researchers excited about this trial's treatments?

Researchers are excited about ASP5541 for prostate cancer because it offers a fresh approach compared to current treatments. Unlike traditional therapies like abiraterone acetate, which mainly target hormone pathways, ASP5541 is designed to be administered every 12 weeks, potentially offering more convenient dosing and better compliance for patients. Additionally, ASP5541 is being tested in combination with prednisone or prednisolone, which may enhance its effectiveness against both metastatic castration-resistant prostate cancer (mCRPC) and metastatic hormone-sensitive prostate cancer (mHSPC). This unique regimen could lead to improved outcomes and quality of life for patients.

What evidence suggests that this trial's treatments could be effective for advanced prostate cancer?

Research has shown that ASP5541 is being tested as a new option for treating advanced prostate cancer in this trial. Participants in different arms of the trial will receive either ASP5541 or the usual treatment with abiraterone acetate (AA). In earlier studies, ASP5541 proved somewhat effective, with about 11-12% of patients experiencing a 50% drop in their prostate-specific antigen (PSA) levels. This drop in PSA levels suggests that the cancer might be responding to the treatment. Unlike AA, which is taken as a tablet, ASP5541 is administered as an injection. This new treatment could be especially helpful for those with advanced prostate cancer who haven't tried ARPI treatments before. ^{2 6 7 8 9}

Who Is on the Research Team?

Medical Monitor

Principal Investigator

Astellas Pharma Global Development, Inc.

Are You a Good Fit for This Trial?

Adult men with advanced prostate cancer that has spread (metastatic) can join. They must have either hormone-sensitive or castration-resistant types and not been treated with ARPIs before. Japanese men are also eligible, regardless of prior ARPI treatment.

Inclusion Criteria

I will not donate sperm during or for 7 months after my treatment ends.

I have metastatic castration-resistant prostate cancer confirmed by scans.

I have been diagnosed with metastatic hormone-sensitive prostate cancer.

Exclusion Criteria

I have taken more than 10 mg of prednisone daily in the last 4 weeks.

I have not had a fever or infection in the last 28 days.

I have a known history of HIV.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive ASP5541 with or without prednisone/prednisolone or abiraterone acetate with prednisone/prednisolone, depending on the cohort

Up to 37 months

Every 12 weeks for ASP5541 administration

Follow-up

Participants are monitored for safety and effectiveness after treatment

Up to 84 months

What Are the Treatments Tested in This Trial?

Interventions

• ASP5541

Trial Overview

The trial tests ASP5541, a new injection form of hormone therapy for prostate cancer, both alone and with steroids (prednisone/prednisolone), against the standard tablet form abiraterone acetate (AA) with steroids. It aims to compare effectiveness and safety in three groups based on cancer type and previous treatments.

How Is the Trial Designed?

Group I: Cohort 3 (mCRPC or mHSPC) Japanese Participants Only Experimental Treatment 3 Interventions

Participants will receive ASP5541 every 12 weeks + prednisone/prednisolone twice daily (for mCRPC) or prednisone/prednisolone once daily (for mHSPC)

Group II: Cohort 2 (mHSPC) Group B Experimental Treatment 1 Intervention

Participants will receive ASP5541 every 12 weeks

Group III: Cohort 2 (mHSPC) Group A (Safety Run In) Experimental Treatment 1 Intervention

Participants will receive ASP5541 every 12 weeks

Group IV: Cohort 1 (mCRPC) Group A Experimental Treatment 3 Interventions

Participants will receive ASP5541 every 12 weeks + prednisone/prednisolone twice daily

Group V: Cohort 2 (mHSPC) Group C Active Control 3 Interventions

Participants will receive abiraterone acetate once daily + prednisone/prednisolone once daily

Group VI: Cohort 1 (mCRPC) Group B Active Control 3 Interventions

Participants will receive abiraterone acetate once daily + prednisone/prednisolone twice daily

Who Is Running the Clinical Trial?

Astellas Pharma Global Development, Inc.

Lead Sponsor

Trials

204

Recruited

123,000+

Tadaaki Taniguchi

Astellas Pharma Global Development, Inc.

Chief Medical Officer

M.D., Ph.D.

Naoki Okamura

Astellas Pharma Global Development, Inc.

Chief Executive Officer

Not available

Citations

1.

clinicaltrials.gov

clinicaltrials.gov/study/NCT07005154

NCT07005154 | A Phase 2 Study to Evaluate the Effects of ...

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 ...

2.

urotoday.com

urotoday.com/conference-highlights/esmo-2025/esmo-2025-prostate-cancer/164044-esmo-2025-phase-1-trial-of-asp5541-prl-02-a-long-acting-intramuscular-depot-injection-of-abiraterone-decanoate-in-patients-with-advanced-prostate-cancer.html

ESMO 2025: Phase 1 Trial of ASP5541 (PRL-02), A Long- ...

In the prior ARPI mCRPC dose expansion cohorts (Cohort D and Cohort E), the confirmed PSA50 response rates were 2/18 (11.1%) and 3/24 (12.5%), respectively.

3.

withpower.com

withpower.com/trial/phase-2-prostate-cancer-5-2025-25993

ASP5541 for Prostate Cancer

This Phase 2 medical study run by Astellas Pharma Global Development, Inc. is evaluating whether ASP5541 will have tolerable side effects & efficacy for ...

4.

clinconnect.io

clinconnect.io/trials/NCT07005154

A Phase 2 Study to Evaluate the Effects of ASP5541 in

This clinical trial is studying a new treatment called ASP5541 for men with advanced prostate cancer that has spread to other parts of the body. The trial aims ...

5.

pmc.ncbi.nlm.nih.gov

pmc.ncbi.nlm.nih.gov/articles/PMC8249852/

Real-World Data on Outcomes in Metastatic Castrate ...

Both abiraterone and enzalutamide have shown to result in significant PSA response rates, as well as PFS and OS benefit in mCRPC patients in the real world ...

6.

clinicaltrials.astellas.com

clinicaltrials.astellas.com/study/5541-CL-0201

A phase 2 study to evaluate the effects of ASP5541 in ...

This study will check the safety of ASP5541 and compare how well ASP5541 works in men with advanced prostate cancer compared to AA.

7.

clinicaltrials.gov

clinicaltrials.gov/study/NCT04729114

A Safety and Dose-finding Study of PRL-02 Depot in Men ...

Men with advanced prostate cancer can take part in this study. Their cancer has come back after previous cancer treatment, or the previous cancer treatment they ...

8.

pubmed.ncbi.nlm.nih.gov

pubmed.ncbi.nlm.nih.gov/40940844/

The Safety of Abiraterone Acetate in Patients with Metastatic ...

This study seeks to describe the safety determined in randomized clinical trials of a systemic treatment for mCRPC and whether safety differs by ...

9.

prnewswire.com

prnewswire.com/news-releases/metastatic-castration-sensitive-prostate-cancer-clinical-trial-pipeline-insights-featuring-35-companies--delveinsight-302275912.html

Metastatic Castration-Sensitive Prostate Cancer Clinical ...

In October 2024, Apalutamide (Erleada) was found to provide a significant improvement in overall survival (OS) at 24 months compared with ...