Learn more about a clinical trial for the potential treatment of castration resistant prostate cancer.

Prostate cancer is one of the most common types of cancer. When the cancer is resistant to hormone therapy, it is called castration resistant prostate cancer (CRPC). It is considered metastatic when it has spread to other parts of the body.

This study is evaluating if an investigational (study) medicine is safe and effective in treating metastatic CRPC, and if it is effective in preventing further resistance to current standard-of-care medications for prostate cancer.

Who may participate

Joining a clinical trial is an important and personal decision. Thank you for your consideration.

This clinical trial may be an option for you if you have been diagnosed with metastatic castration resistant prostate cancer that has progressed from your last therapy (by either scans or PSA elevation). To participate, you must not have received previous treatment with Xtandi (enzalutamide) or undergone more than one round of chemotherapy (e.g. Taxotere).

There are other requirements for participation in the study. The study doctor will explain these to you.


Metastatic Castration Resistant Prostate Cancer (CRPC)


18+ years



Each clinical study has its own guidelines for who can participate, called eligibility criteria. However, only the research study staff can determine if you qualify to enroll in the study.

View more eligibility criteria

What to expect

If you decide to participate, the study team will conduct a screening visit to determine if this study is a good fit for you.

Participants will be randomly assigned to receive the current standard-of-care medicine enzalutamide, or the study medicine in combination with enzalutamide. The study medicine is an oral tablet taken twice a day in 21-day cycles until your cancer has progressed, disappeared, or you decide to leave the clinical trial.

If you are not initially assigned to receive enzalutamide and tests show that your cancer has progressed during your time in the clinical trial, you will have the option to begin taking the study medicine in addition to enzalutamide. You will be able to continue taking the study medicine and enzalutamide as long as you and your doctor believe it is a benefit to you.

Length of study treatment

About 2 years

Number of study visits

3 visits for cycles 1-5; 2 visits for cycles 6-12; 1 visit for cycles 12 and beyond

Long-term follow up

You will be asked to attend a visit at the study clinic 28 days after last treatment cycle

Clinical trials allow researchers to compare investigational medicines with current approved treatments. They help us understand if the possible benefits of a potential treatment option outweigh the risks.

Every modern medicine we have today was first tested in clinical trials. Thousands of volunteers around the world take part in clinical trials every year.

About clinical trials

About clinical trials

Men for Prostate Cancer – Pfizer Clinical Trials
Men for Prostate Cancer – Pfizer Clinical Trials

Frequently Asked Questions

How long will I be in this study?

Your time in the clinical trial will vary depending on how many treatment cycles you complete. You will be able to continue taking the study medicine for as long as you and your doctor believe it is of benefit to you. 

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What are the possible benefits of participating?

This clinical trial may not provide any direct benefit to you. If you choose to participate, you will receive an investigational and/or standard-of-care medication that may improve your prostate cancer. Your prostate cancer and health will be monitored regularly throughout. Additionally, you will be contributing to research that will help us learn more about metastatic castration resistant prostate cancer and may help others with prostate cancer in the future.

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What are the possible risks of participating?

All clinical trials have some risks. Your study doctor will discuss all the possible risks and benefits of participating with you before you choose to enroll. You can choose to no longer participate in the clinical trial at any time.

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What if I change my mind about participating?

Your participation in this clinical trial is completely optional. You can choose to stop participating at any time, for any reason. Choosing not to participate in this clinical trial will not affect your future medical care or prostate cancer treatment. 

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How many appointments will I need to attend?

The number of required study visits will vary depending on the number of treatment cycles completed. In addition to the Screening visit, participants will need to attend at least three clinic visits per treatment cycle for the first five cycles, and two clinic visits for every cycle thereafter. Participants will also need to attend a follow-up visit about one month after completing their final treatment cycle.

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What will happen at study visits?

What happens at each study visit will vary, but may include questions about your medical history, cancer diagnosis, and medications, physical exams, blood draws, biopsies (optional), electrocardiograms (ECGs), and CT/MRI/bone scans.

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Learn more
View locations for this study

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    Steps to join a clinical trial