New hormonal medicines have expanded the treatment options available for men with advanced prostate cancer. Unfortunately, not all men benefit from these medicines. For some men, hormonal medicines may only work for a while and then stop working. For others, they may not work at all.

Early research has shown that men who test positive for “AR-V7” are less likely to benefit from Zytiga®, or Xtandi®, which are the only two approved hormonal medicines for patients whose castrate-resistant prostate cancer (CRPC) has spread. AR-V7 can be found through a simple blood test.

Using blood tests to help choose medicines has improved results in several types of cancer.


The ARMOR3-SV clinical trial is for men with CRPC that is metastatic (has spread beyond the prostate to other parts of the body), who have not yet been treated with chemotherapy or certain oral hormonal medicines, and whose cancer is progressing.

The ARMOR3-SV clinical trial will test whether galeterone, an experimental medicine, is helpful for patients who have a substance in the blood called “AR-V7”. The trial will compare galeterone against Xtandi® in men who test positive for AR-V7.

Galeterone is the first in a new class of medicines for patients who have AR-V7. Research has shown that metastatic CRPC patients who have AR-V7 may be less likely to benefit from existing hormonal medicines like Xtandi®.

If you have metastatic CRPC, ask your doctor to be tested for AR-V7 to see if you are eligible to participate in the ARMOR3-SV clinical trial of galeterone.


Androgens are a type of hormone, including testosterone,that control male characteristics. In some men, androgens also cause prostate cancer to grow by attaching to a protein in prostate cells. This protein is called an androgen receptor (AR).

Hormonal medicines that block the production or action of androgens are routinely used to treat prostate cancer. But for men with an abnormal form of AR called AR-V7, these hormonal medicines are less likely to work.

Galeterone works differently. It may reduce the production of androgens and prevent androgens from attaching to ARs, it also may reduce the number of ARs in the prostate cancer tumor. Together, these actions of galeterone may help keep prostate cancer from growing.

If you have metastatic CRPC, ask your doctor to be tested for AR-V7. If you test positive for AR-V7, you may be eligible to participate in the ARMOR3-SV clinical trial.


The ARMOR3-SV clinical trial is for men with CRPC–prostate cancer that is no longer responding to traditional hormonal medicines–that has spread beyond the prostate to other parts of the body.

You may be eligible to participate in this trial if you:

• Tested positive for AR-V7
• Had removal of both testes or are on medicine to stop making testosterone
• Have not previously been treated with either Xtandi® or Zytiga®
• Have not previously been treated with chemotherapy for CRPC

If you are interested in participating in ARMOR3-SV, or have additional questions, talk to your doctor, or visit for more details.

Choosing to participate in a clinical trial is an important personal decision. If you are considering participating in the ARMOR3-SV clinical trial, you may have a lot of questions.

What is a clinical trial?
A clinical trial is a research study that tests whether a new treatment is safe and effective to use. A randomized clinical trial tests the new medicine by comparing it to an approved medicine that is currently used to treat your disease. Clinical trials are an option for many people with cancer.

What is the purpose of the ARMOR3-SV clinical trial?
ARMOR3-SV is a randomized clinical trial that will compare galeterone to Xtandi®, an oral hormonal medicine often used to treat CRPC, in patients with CRPC that has spread beyond the prostate and who test positive for AR-V7.

How many people are participating in the ARMOR3-SV trial?
Approximately 150 men with prostate cancer from the United States, Canada, Europe, and Australia are expected to take part in this trial.

Will I receive the experimental medication or the standard treatment?
Half of the men in the ARMOR3-SV clinical trial will receive galeterone and half will receive Xtandi®. Neither you nor your doctor can choose which medication you receive. A computer will randomly assign you to your study treatment.

When will I get treatment?
You will take your study drug once a day. In addition, you will need to visit the clinic every 4 weeks for at least 12 months. You will also have imaging scans every 8 weeks to see what is happening with your tumor. Blood samples and other tests will also be done during your clinic visits.

What are the possible side effects?
You may experience side effects from either medicine in the clinical trial. All potential side effects will be explained to you in detail if you decide to enroll in the clinical trial.

Can I leave a clinical trial once I have joined it?
Yes. You can withdraw from the ARMOR3-SV clinical trial at any time and for any reason.

How much will it cost me?
Regardless of which study drug you are assigned to receive, both galeterone and Xtandi® will be provided at no cost to you. Study-related medical examinations and laboratory tests that are not part of your routine care for your condition will be provided free of charge.

Questions about ARMOR3-SV?

If you or someone you know has CRPC and has questions about ARMOR3-SV, please contact us.