Xofigo (radium Ra 223 dichloride) is a drug designed to treat advanced prostate cancer that has not responded to testosterone-lowering drugs. This type of cancer is also called castration-resistant prostate cancer.
According to the American Cancer Center, an estimated 180,890 new cases of prostate cancer will be diagnosed in 2016 and 26,120 men will die from the disease.
Testosterone, the male sex hormone, stimulates the growth and spread of prostate cancer. For this reason, treatment to lower testosterone can help slow the disease’s progression. However, some forms do not respond to a reduction in this hormone. These cases are referred to as castration-resistant.
Metastatic prostate cancer moves into the bones in most patients. When cancer reaches the bone, the patient is much more vulnerable to skeletal events; these can include pain in the bones and fractures that occur during even quite gentle movements.
Skeletal events are the main cause of ill health and death in men with castration-resistant prostate cancer.
If the cancer has reached the bones but not spread to other organs, Xofigo can extend the time before skeletal events occur.
Dr. Richard Pazdur, director of the Office of Hematology and Oncology Products in the Center for Drug Evaluation and Research, U.S. Food and Drug Administration (FDA), explains: “Xofigo binds with minerals in the bone to deliver radiation directly to bone tumors, limiting the damage to the surrounding normal tissues.”
According to Dr. Kemal Malik, member of the Bayer HealthCare Executive Committee and Head of Global Development:
“Xofigo shows a favorable safety profile and has the potential to improve patient outcomes in a completely novel way. Radium 223 emits alpha particles that affect cancer cells in bone metastases and may contribute to a survival improvement.
[Xofigo provides] prostate cancer patients, and the physicians who care for them, with a new and innovative treatment option.”
Dr. Kemal Malik
Xofigo may cause the following side effects:
- Swelling of a foot, leg, or ankle
- Nausea, vomiting, and diarrhea
- Anemia (low level of red blood cells)
- Lymphocytopenia (low level of lymphocytes – a type of white blood cell)
- Leukopenia (low level of white blood cells)
- Neutropenia (low level of infection-fighting white blood cells)
Rarely, patients receiving Xofigo may also experience dehydration, reactions at the injection site, and kidney failure.
It is not recommended that patients taking Xofigo should undergo chemotherapy at the same time. This is because the combination of drugs can cause bone marrow activity to decrease, which results in fewer red blood cells, white blood cells, and platelets.
In a 2013 study, patients with metastatic castration-resistant prostate cancer taking Xofigo lived about 3.5 months longer, on average, than those who were given a placebo. Xofigo was also found to improve quality of life for these patients and extend the period of time before their first skeletal problem.
Despite the life-extending properties of Xofigo, some experts have expressed frustration that oncologists largely regard Xofigo as simply a pain-relieving drug for prostate cancer patients.
Speaking recently to the oncology website Cure, cancer researcher Phillip J. Koo of the University of Colorado Hospital in Aurora, explained that oncologists tend to think of radiopharmaceutical drugs as palliative treatments – drugs to make people feel more comfortable but not necessarily treat the disease. Oncologists fail to take into account that, because it is an alpha emitter, Xofigo belongs to a different class of treatments:
“I think the biggest challenge is that oncologists still see it as a palliative tool […] It is still being put in that same type of class when it really it doesn’t belong there. This is because it’s an alpha emitter and it actually improves overall survival. [The trial] data have shown that Xofigo can be given safely before or after chemotherapy.”
Phillip J. Koo