Enzalutamide (Xtandi)

Xtandi, which is taken orally, is an androgen receptor inhibitor, which blocks the ability of androgens from accessing the cancer cell’s nucleus to fuel its growth. The FDA approved it in 2012 to treat metastatic castration resistant prostate cancer in men who have received and failed docetaxel.  This is the same disease stage for which both abiraterone and cabazitaxel are also approved.  Sometimes enzalutamide is referred to as a “super Casodex” as it has a similar, but much more powerful, antiandrogen effect.

Unlike abiraterone, enzalutamide does not require simultaneous administration of a steroid such as prednisone.

The most common side effects reported in the clinical trial of enzalutamide were:

  • Fatigue
  • Back pain
  • Diarrhea
  • Hot flashes
  • Peripheral edema (swelling in the hands and feet)
  • Musculoskeletal pain
  • Headache
  • Upper respiratory infection
  • Muscular weakness
  • Dizziness
  • Insomnia
  • Lower respiratory infection
  • Spinal cord compression
  • Hematuria
  • Paresthesia

Listening to the feedback on the advanced prostate cancer online support group fatigue seem to be the side effect experienced by most of the men taking the drug.  They report an overwhelming fatigue that will often interfere with day-to-day life.