RecruitingPHASE2INTERVENTIONAL

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

This study is testing a new way to treat advanced prostate cancer called ASP5541. This new medicine is given as an injection, while the current similar treatment, abiraterone acetate, is taken as a tablet. The study aims to see if ASP5541 is as safe and works as well as abiraterone acetate in men whose prostate cancer has spread to other parts of their body. Some men in the study will receive ASP5541 with a steroid medicine, and others will receive ASP5541 alone. The study will also include a group of Japanese men to understand how the treatment works for them. Participants will have regular check-ups and scans to monitor their health and the cancer.

At a glance

Status

Recruiting

Phase

PHASE2

Sponsor

Astellas Pharma Global Development, Inc.

Enrolment target

218

Start

19 Jun 2025

Estimated completion

31 May 2032

Prostate Cancer Metastatic Castration-Resistant Prostate Cancer Metastatic Hormone Sensitive Prostate Cancer

What is this study about?

Prostate cancer often relies on a male hormone called testosterone to grow. Standard treatments, known as hormone therapy, work by lowering the amount of testosterone in the body. There's another type of hormone therapy called ARPIs, which either reduce testosterone production or stop it from reaching cancer cells. A common ARPI used for advanced prostate cancer is abiraterone acetate, typically given as a tablet along with a steroid like prednisone or prednisolone to help manage any side effects.

This study is looking at a new version of abiraterone acetate, called ASP5541, which is given as an injection into a muscle. The main goal is to find out if ASP5541 is as safe and effective as the current tablet treatment, abiraterone acetate, for men with advanced prostate cancer where the cancer has spread. Researchers want to compare ASP5541 given both with and without the steroid medicines. They will also look at the safety of ASP5541 in a group of Japanese men with advanced prostate cancer.

Taking part in this study means you would be helping doctors understand if this new injection could be a good treatment option in the future. It's a 'Phase 2' study, which means researchers are checking the best dose and how well the treatment works in a larger number of people, as well as continuing to monitor safety.

Key takeaways

This study is for men with advanced prostate cancer where the cancer has spread.
It tests a new injectable medicine, ASP5541, against a standard tablet treatment.
The aim is to check how safe and effective ASP5541 is.
Participants will have regular check-ups, scans, and blood tests.
Some participants will also take steroid tablets alongside the main study medicine.
Participation is voluntary, and you can withdraw at any time.

Who may be eligible?

This study is particularly looking for adult men with prostate cancer that has spread to other parts of the body. This is known as 'advanced' prostate cancer. Your doctor will be able to confirm if your cancer falls into one of these types: cancer that still needs testosterone to grow, or cancer that continues to grow even when testosterone levels are low.

To be considered, your prostate cancer must have been officially diagnosed by looking at tissue samples. You should also be generally well and able to manage daily activities, even if you experience some bone pain. You must also be expected to live for at least another 6 to 12 months, depending on the type of advanced prostate cancer you have. You'll need to be able to understand and follow all the study instructions and arrangements.

Quick self-check

Are you an adult man with prostate cancer that has spread?
Has your cancer been confirmed by a doctor looking at tissue samples?
Are you generally well and able to do most daily activities?
Are you currently receiving, or have you had, hormone therapy for your prostate cancer?
Are you able to understand and follow study instructions?

This is a guide only — the research team will confirm whether you can take part.

What does participation involve?

If you decide to join this study, you will be assigned to one of three treatment groups. Depending on your group, you will receive either ASP5541 (as an injection into a muscle every 12 weeks), or abiraterone acetate (as daily tablets). Some groups will also take prednisone or prednisolone tablets, either once or twice daily. All participants will continue to receive their usual hormone therapy.

You will have regular clinic visits throughout the study and after your treatment ends. These visits will include health check-ups and monitoring for any medical problems. Some men in one of the groups will also need to check their blood pressure weekly at home. On certain visits, you will have scans to see if your cancer has changed. The number of visits and the types of checks will depend on your health and how long you've been in the study.

Potential risks and benefits

Taking part in any clinical study has potential benefits and risks. A potential benefit of this study could be access to a new treatment for advanced prostate cancer that might be more convenient (as an injection every 12 weeks). However, as ASP5541 is still being studied, it's not known if it will work better than or even as well as existing treatments, and there might be side effects or medical problems not yet fully understood. It's important to remember that you can stop participating in the study at any time, for any reason, without it affecting your future medical care.

Locations (33)

Clearview Cancer Institute
Huntsville, United States· Recruiting
H. Lee Moffitt Cancer Center
Tampa, United States· Recruiting
Associated Urological Specialists
Chicago Ridge, United States· Recruiting
Ochsner Health - Ochsner Medical Center - New Orleans
New Orleans, United States· Recruiting
New Mexico Oncology Hematology Consultants
Albuquerque, United States· Recruiting
Solaris Health - The Urology Group
Cincinnati, United States· Recruiting
Carolina Urologic Research Center
Myrtle Beach, United States· Recruiting
Tennessee Oncology Nashville
Nashville, United States· Recruiting
University of Virginia Cancer Center
Charlottesville, United States· Recruiting
UW Health Carbone Cancer Center
Madison, United States· Recruiting
Subei People's Hospital
Yangzhou, China· Recruiting
The Second Hospital of Tianjin Medical University
Tianjin, China· Recruiting

+21 more sites — see the official record for the full list.

Common questions

What is advanced prostate cancer?

This means your prostate cancer has spread to other parts of your body. It might still depend on male hormones to grow, or it might be growing even without them.

What is ASP5541?

ASP5541 is a new version of an existing prostate cancer medicine (abiraterone acetate). It's given as an injection instead of a tablet.

Why would I get an injection instead of a tablet?

The study is trying to find out if the injection works just as well and is as safe as the daily tablet, potentially offering a more convenient treatment option for the future.

Will I have to take other medicines in the study?

Yes, depending on your group, you might also take steroid tablets like prednisone or prednisolone, and you'll continue with your standard hormone therapy.

What does a 'Phase 2' study mean?

In a Phase 2 study, researchers are checking how well a new treatment works, finding the best dose, and continuing to monitor its safety in a larger group of people.

How to find out more

Astellas Pharma Global Development, Inc.

Astellas.registration@astellas.com 800-888-7704 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.