A study testing ASP5541 compared to abiraterone acetate in patients with advanced prostate cancer

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What is this study about?

This study involves people with prostate cancer that has spread to other parts of the body. The study looks at two specific types of this condition: one where the cancer no longer responds to treatments that lower male hormones and another where the cancer still responds to such treatments. The study uses a medicine called ASP5541, which is given as an injection into the muscle. Some people in the study will also take steroid tablets called prednisone or prednisolone along with the injection. For comparison, some people will receive a different medicine called abiraterone acetate, which is taken as a tablet together with prednisone or prednisolone. The purpose of this study is to find out how well ASP5541 works in treating prostate cancer and to check how safe it is for patients to use.

The study is divided into three groups of people. The first group includes people whose cancer has spread and no longer responds to hormone treatments. These people will receive either ASP5541 with a steroid or abiraterone acetate with a steroid. The second group includes people whose cancer has spread but still responds to hormone treatments. Some people in this group will receive ASP5541 without steroids, while others will receive abiraterone acetate with steroids. The third group includes people from Japan with either type of prostate cancer who will receive ASP5541 with steroids. All people in the study will continue to receive treatments that keep male hormone levels low.

During the study, doctors will measure a substance in the blood called PSA, which is a marker for prostate cancer activity. They will check how much the PSA levels drop and whether they become very low or undetectable. Doctors will also use imaging tests such as CT scans, MRI scans, and bone scans to see if the cancer grows or shrinks. The study will monitor how long it takes before the cancer gets worse and will track any side effects that people experience. Safety checks will include blood tests, heart tests called electrocardiograms, blood pressure measurements, and general physical examinations. The study will also ask people to complete questionnaires about their pain levels and overall well-being.

1 Initial Treatment Assignment

Upon joining the study, you will be assigned to one of three groups based on your specific type of prostate cancer and other medical factors.

Group 1 is for participants with metastatic castration-resistant prostate cancer, which means prostate cancer that has spread to other parts of the body and no longer responds to hormone therapy that lowers testosterone.

Group 2 is for participants with metastatic hormone-sensitive prostate cancer, which means prostate cancer that has spread to other parts of the body but still responds to hormone therapy.

Group 3 is specifically for Japanese participants with either metastatic castration-resistant prostate cancer or metastatic hormone-sensitive prostate cancer.

2 Medication Administration

If you are assigned to Group 1, you will receive either ASP5541 (also called abiraterone decanoate) combined with prednisone or prednisolone, or you will receive abiraterone acetate combined with prednisone or prednisolone.

If you are assigned to Group 2, you will receive either ASP5541 without additional steroids, or abiraterone acetate combined with prednisone or prednisolone.

If you are assigned to Group 3, you will receive ASP5541 combined with prednisone or prednisolone.

ASP5541 (abiraterone decanoate) is given as an injection into the muscle.

Abiraterone acetate, prednisone, and prednisolone are taken by mouth.

3 Regular Monitoring and Assessments

Throughout the study, you will undergo regular monitoring to evaluate how the treatment is working and to check for any side effects.

Blood tests will be performed regularly to measure prostate-specific antigen (PSA), which is a protein produced by the prostate that can indicate how the cancer is responding to treatment.

Blood tests will also check your general health, including blood cell counts, kidney and liver function, and levels of certain chemicals in your blood.

Urine tests will be conducted to assess kidney function and other health indicators.

If you are in Group 2, additional urine tests will measure potassium and creatinine levels to monitor for specific side effects.

Blood tests will measure testosterone levels to ensure hormone therapy is working effectively.

Electrocardiograms (ECGs), which are tests that measure the electrical activity of your heart, will be performed at scheduled intervals.

Your vital signs, including blood pressure, heart rate, and temperature, will be measured regularly.

Physical examinations will be conducted to assess your overall health.

Your activity level and ability to perform daily tasks will be evaluated using the ECOG performance status score.

4 Imaging Studies

Imaging scans will be performed at scheduled times to check if the cancer has grown or spread.

These may include bone scans, which look for cancer in the bones, CT scans (computed tomography), MRI scans (magnetic resonance imaging), or PSMA-PET scans (prostate-specific membrane antigen positron emission tomography).

The scans help determine if the treatment is controlling the cancer or if the disease is progressing.

5 Questionnaires

You will be asked to complete questionnaires about your symptoms and quality of life.

These questionnaires will include questions about pain levels using the Brief Pain Inventory-Short Form (BPI-SF).

The information you provide helps assess how the treatment affects your daily life and well-being.

6 Safety Monitoring

The study team will monitor you for any side effects or adverse reactions to the treatment.

Special attention will be given to certain side effects, such as low potassium levels in the blood (hypokalemia) and high blood pressure (hypertension), particularly in Group 2.

Any serious or unexpected side effects will be recorded and managed appropriately.

If you are in Group 3, safety monitoring will be particularly focused on how Japanese participants respond to the treatment.

7 Contraception Requirements

Throughout the treatment period and for a specified time afterward, you must follow specific contraception requirements.

If you have a female partner who can become pregnant, you must use approved methods of birth control during treatment and for 7 months after your final dose of ASP5541 or for 3 months after your final dose of abiraterone acetate.

If your partner is pregnant, you must use a condom during sexual activity throughout the treatment period and for the same time periods after your final dose.

You must not donate sperm during treatment and for 7 months after your final dose of ASP5541 or for 3 months after your final dose of abiraterone acetate.

8 Study Restrictions

You must not participate in any other interventional study while receiving treatment in this study.

You are expected to attend all scheduled visits and follow all study procedures.

You must inform the study team of any changes in your health or any new medications you are taking.

9 Duration of Participation

The study is expected to continue until May 2032, though your individual participation time may vary depending on how you respond to treatment and your overall health.

The study team will inform you of the specific schedule for your visits and assessments.

Your participation will continue as long as the treatment is beneficial and you do not experience unacceptable side effects.

Who Can Join the Study?

You must be male and at least 18 years old at the time you agree to join the study
You must have prostate cancer that has been confirmed by tissue examination showing a specific type called adenocarcinoma, which means cancer that started in gland cells of the prostate, without certain aggressive features
You must have cancer that has spread to other parts of your body, shown on imaging tests such as bone scans, CT scans (detailed x-ray pictures), MRI (magnetic imaging), or PSMA-PET (a special scan that finds prostate cancer cells)
Your physical condition must be rated as 0 or 1 on a scale called ECOG performance status, which measures how well you can perform daily activities, or rated as 2 if your limitations are due to bone pain
If your cancer is hormone-sensitive, meaning it still responds to hormone treatment, you must be expected to live at least 12 months
If your cancer is castration-resistant, meaning it no longer responds to hormone treatment that lowers testosterone, you must be expected to live at least 6 months
You must be able to understand and follow all study requirements and procedures, including filling out questionnaires about how you feel
You must agree to use effective birth control methods with any female partner who can become pregnant during the treatment and for 7 months after your last dose of the study drug ASP5541, or for 3 months after your last dose if you receive the drug called abiraterone acetate
You must agree to use a condom with any pregnant partner during treatment and for 7 months after your last dose of ASP5541, or for 3 months after your last dose of abiraterone acetate
You must agree not to donate sperm during treatment and for 7 months after your last dose of ASP5541, or for 3 months after your last dose of abiraterone acetate
You must provide your written agreement to participate in the study after understanding all requirements and restrictions
You must agree not to join another research study while you are receiving the study drug in this trial

Who Cannot Join the Study?

The study is only for male patients, so women cannot participate
Patients who are children or adolescents cannot participate, as the study is only for adults and elderly people
Patients who do not have prostate cancer cannot participate in this study
Patients who have already received treatment with androgen receptor pathway inhibitors, which are medicines that block certain hormones that help prostate cancer grow, may not be eligible
Patients whose cancer has not spread to other parts of the body may not be eligible, as the study focuses on metastatic cancer, which means cancer that has spread beyond the prostate to other organs or bones
Patients who do not meet the specific disease stage requirements for each group in the study cannot participate

Where you can join this trial?

Verified and Recommended Sites

No sites found in this category

Verified Sites

Site Name	City	Country
Institut Gustave Roussy	Villejuif	France
Centre Jean Perrin	Clermont Ferrand	France
Centre Hospitalier Universitaire De Lille	Lille	France
IRCCS Humanitas Research Hospital	Rozzano	Italy

Other Sites

Site Name	City	Country
IRCCS Istituto Nazionale Tumori Fondazione Pascale	Naples	Italy
Azienda Provinciale Per I Servizi Sanitari	Trento	Italy
Azienda Ospedaliero Universitaria Di Modena	Modena	Italy
Hospital General Universitario Gregorio Maranon	Madrid	Spain
Studienpraxis Urologie Susan Feyerabend MD Tilman Todenhoefer MD PhD GbR	Nuertingen	Germany
Europejskie Centrum Zdrowia Otwock Sp. z o.o.	Otwock	Poland
Urologie Heinsberg	Heinsberg	Germany
Ospedale San Raffaele S.r.l.	Milan	Italy
Hospital Clinic De Barcelona	Barcelona	Spain
Universidade De Santiago De Compostela	Santiago De Compostela	Spain
Hopital Beaujon	Clichy	France
Clinique Victor Hugo	Le Mans	France
Ieiwat Iglmzdpt Fuapdsudhmdnm Oojhzkcnyal	Rome	Italy
Izbkqmtk Clthmy Dfwbevcosyivipejd	L'hospitalet De Llobregat	Spain
Chfspuv Uezmiwmhbgy	Myslowice	Poland
Cnurpv dx Rtheaajsbqubb &cefzkg Crsxohia Svfeki Afge	STRASBOURG, Alsace	France
Nktmhylb Icmazcii Onnurzkri Iaw Mxgwd Sjbjqnvpftduxhjuxnbbglfzcgqz Ifdggggv Btlxiwzj	Cracow	Poland
Uohsreprhuilsj Cqeqgsq Kvhmagqrr	Gdansk	Poland
Hadgxxwh Dt La Smekx Cxav I Sqmy Pdo	Barcelona	Spain

Trial status

Country	Status	Recruitment Start
France	Not yet recruiting	01.10.2025
Germany	Recruiting	01.10.2025
Italy	Recruiting	01.10.2025
Poland	Not yet recruiting	01.10.2025
Spain	Recruiting	01.10.2025

Trial locations

Investigated drugs:

ASP5541 is an investigational medication being studied for the treatment of advanced prostate cancer. In this trial, it is being tested alone or in combination with steroids called prednisone or prednisolone to see how well it works and how safe it is for patients with different types of prostate cancer that has spread to other parts of the body.

Prednisone is a steroid medication that is commonly used to reduce inflammation and suppress the immune system. In this trial, it is being given together with some of the investigational treatments to help manage side effects and improve outcomes for patients with prostate cancer.

Prednisolone is a steroid medication similar to prednisone that helps reduce inflammation in the body. In this trial, it may be used as an alternative to prednisone and is given in combination with some of the treatments being studied for prostate cancer.

Abiraterone acetate is an approved medication used to treat prostate cancer by blocking the production of male hormones that can help cancer cells grow. In this trial, it is being used as a comparison treatment to see how the investigational medication ASP5541 performs against this standard therapy.

Prostate Cancer – Prostate cancer is a disease that occurs when abnormal cells grow uncontrollably in the prostate gland, which is a small walnut-shaped organ in men located below the bladder. The cancer typically develops slowly and may initially remain confined to the prostate gland. As the disease progresses, it can spread beyond the prostate to nearby tissues and organs. In more advanced stages, the cancer cells may travel through the bloodstream or lymphatic system to distant parts of the body, particularly bones. Metastatic castration-resistant prostate cancer refers to a stage where the cancer has spread to other parts of the body and continues to grow despite treatments that lower testosterone levels. Metastatic hormone-sensitive prostate cancer describes cancer that has spread beyond the prostate but still responds to treatments that reduce hormone levels in the body.

Trial ID:

2024-517653-27-00

Protocol code:

5541-CL-0201

NCT ID:

NCT07005154

Trial Phase:

Therapeutic exploratory (Phase II)

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A study testing ASP5541 compared to abiraterone acetate in patients with advanced prostate cancer

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?