ASP5541-201: A Phase 2 Study of Efficacy and Safety in Advanced Prostate Cancer
Research type
Research Study
Full title
A Phase 2, Open-label, Multi-cohort Study to Assess the Efficacy and Safety of ASP5541 in Participants with Advanced Prostate Cancer
IRAS ID
1012088
Contact name
Yuki Tu
Contact email
Sponsor organisation
Astellas Pharma Global Development Inc.
Eudract number
2024-517653-27
Research summary
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 inhibitor 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. This type of treatment is usually given as a tablet with a steroid called prednisone/prednisolone to manage any medical problems from the hormone therapy. ASP5541 is a different form of AA. It is given as an injection into the muscle. In this study, ASP5541 will be given to men with advanced prostate cancer, both with and without prednisone/prednisolone. This study will check the safety of ASP5541 and compare how well ASP5541 works in men with advanced prostate cancer compared to AA.
There are limited treatment options for men with advanced prostate cancer, so there is a high unmet medical need. ASP5541 works in a similar way to AA so it may also help men with advanced prostate cancer. Although people may not get direct benefit from taking part, this study will help provide more information on how ASP5541 can treat men with advanced prostate cancer. Those taking part should think about the following risks or potential medical problems: AA may cause high blood pressure, low potassium, fluid retention, adrenal insufficiency (the adrenal gland cannot produce enough cortisol), liver disorders, and low blood sugar. These medical problems may also happen with ASP5541. Other potential medical problems include: pulmonary oil microembolism (POME) a lung problem that causes breathing difficulties, throat tightening, chest pain, dizziness, and fainting; and injection site reactions.
**Please refer to Protocol Plain Language Synopsis attached to this submission**
REC name
London - Westminster Research Ethics Committee
REC reference
25/LO/0782
Date of REC Opinion
8 Dec 2025
REC opinion
Further Information Favourable Opinion