Zytiga Compared to Xtandi for Prostate Cancer Treatment

If you are a man who has been diagnosed with advanced prostate cancer that has not responded to hormone therapy, you have several treatment options from which to choose. The medication Xtandi (enzalutamide) was approved by the Food and Drug Administration on August 31, 2012. Another medication is Zytiga (abiraterone acetate). Are either of these new hormone therapies appropriate to treat your prostate cancer? Before you can answer that question, you need to consult your healthcare provider and also learn all you can about Zytiga compared to Xtandi as treatment choices. The following questions can help you with your decision process.

How Do Xtandi and Zytiga Work?

Xtandi and Zytiga have some similarities, but there is still a difference in how they work.  Xtandi is the first entry into a new class of medications called androgen inhibitors. This class of drugs was specially designed to interrupt the ability of the hormone testosterone to bind to prostate cancer cells. This is critical because prostate cancer cells need testosterone for reproductive and growth purposes, and so Xtandi can be an effective deterrent.

Zytiga works by targeting a protein called cytochrome P450 17A1 (CYP17A1), which plays a significant role in testosterone production. Unlike any other hormone therapy for prostate cancer, Zytiga is able to reduce the production of testosterone from three sources: the adrenal glands, the testes, and the prostate tumor.

Who is Eligible for Xtandi vs Zytiga?

The population of men who are eligible for treatment with either Xtandi or Zytiga is the same: men who have metastatic prostate cancer that has not responded to hormone therapy and who also have failed to respond to the chemotherapy drug docetaxel.

How Do You Take Zytiga compared to Xtandi?

Xtandi is a pill that is taken daily. The average treatment period, based on clinical trials, is 8 months.

Zytiga also is an oral medication taken once per day, but the dose is accompanied by  twice daily dosing with a steroid (prednisone). The average length of treatment is 8 months.

What Are the Side Effects of Xtandi Compared to Zytiga?

Side effects experienced by men who take Xtandi may include anxiety, back pain, bloody urine, diarrhea, dizziness, fatigue, headache, hot flashes, joint pain, muscle weakness, musculoskeletal pain, respiratory infections (upper and lower), sleep problems, spinal cord compression, tingling sensation, and tissue swelling. Seizures were reported in about 1% of patients.

Men who take Zytiga may experience cough, diarrhea, fluid retention, heartbeat disorders, high blood pressure, hot flashes, joint swelling, low potassium levels, muscle aches, upper respiratory tract infection, upset stomach, urinary frequency, and urinary tract infection. In addition, it should be noted that prednisone is taken along with Zytiga. Steroids are associated with a weakening of the immune system, making individuals susceptible to infection.

What Is the Cost of Xtandi vs Zytiga?

The monthly cost of treatment with Xtandi is $7,450. Although Medicare and most insurance companies will likely cover the cost of Xtandi, men should consult their insurance providers.

Zytiga has a price tag of about $5,000 per month. Treatment is covered by Medicare and most insurance companies.

How Effective is Xtandi vs Zytiga?

The effectiveness and safety of Xtandi were demonstrated in a clinical trial that included 1,199 men who were given either Xtandi or placebo. Median overall survival among men who took Xtandi was 18.4 months compared with the placebo group at 13.6 months. Thus Xtandi extended survival by a median of 4.8 months.

Zytiga was evaluated in a clinical trial with nearly as many participants (1,195 patients) who received either Zytiga once daily plus prednisone twice daily or a placebo. Median overall survival for men who took Zytiga was 14.8 months compared with 10.9 months in the placebo group. This resulted in a median extended survival of 3.9 months.

Xtandi vs Zytiga, Is One For You?

Men who have advanced prostate cancer have several medical choices. Both Xtandi and Zytiga are oral medications that have similar lengths of treatment and many of the same side effects, but with different treatment regimens, median extended survival times, and costs. When choosing a treatment for prostate cancer, whether it includes Xtandi, Zytiga, or one of the other available therapies, men need to examine all the risks and benefits in light of their personal and medical needs, and consult their healthcare providers and loved ones.