known as Somatostatin or somatostatin analogues (octreotide acetate or lanreotide).
How is it taken? Injection or IV.
Dosage Given as an injection or intravenously (IV) in a variety of dosages.
Advantages This is a new potential secondary hormonal treatment. Sandostatin is known for its lack of side effects. The only short-term notable side effects are some fatigue and diarrhea, especially during the first month of the treatment.
The catch Since it is new as a secondary hormonal treatment, the true positives and negatives of using these drugs for HRPC are not yet clear. Researchers are not sure whether it is even effective against HRPC.
What else do I need to know? This is a drug that inhibits growth hormone (GH) production. It is best known for treating children and adults who produce too much GH (known as gigantism in children and acromegaly in adults). GH itself is a drug that has been given in some anti-aging clinics, but the research supporting this hormone for anti-aging is weak. There are also possible serious long-term toxicity issues. In fact, GH is a troubling medication because it causes the release of another hormone known as insulin-like growth factor 1 (IGF1). Some research studies appear to show that higher levels of IGF1 may promote tumor growth. The fact that Sandostatin may help some with HRPC provides some support for this argument.
Some preliminary research suggests that, when a drug like Sandostatin is combined with a steroid medication (such as dexamethasone), it may allow hormone therapy to be slightly effective again for a time, or it may block IGF1 or another factor that allows a prostate cancer cell to survive. Using Sandostatin as a treatment is a new concept so, as always, talk to your doctor for the latest information on it.
Question: Is combining secondary hormonal treatments an option?
Answer: Yes. There is now some preliminary research to suggest that secondary hormonal therapies may be better when they are given in combination. This seems to make sense, because each medication targets a separate anti-cancer pathway. Estrogen kills cells directly; high-dose anti-androgens block a receptor; ketoconazole reduces adrenal hormones and self-hormone production in tumors; and Sandostatin reduces the amount of a type of fuel that could promote tumor growth. Thus, it is not surprising that a few studies have shown a higher response rate in men with HRPC when the drugs are combined. There are even some new studies using secondary hormone therapies with medications such as dutasteride (5-alpha-reductase inhibitor) with ketoconazole, for example, or a bone maintenance drug (bisphosphonate) with multiple therapies. However, other studies have shown mixed results, so talk to your doctor to determine the best course of treatment for your situation.
The next chapters in the book will consider HRPC treatments approved by the U.S. Food and Drug Administration (FDA). As was mentioned earlier, there are exciting new drug therapies being researched currently. Since this book was started, several new drugs have been added to the following section, demonstrating that research in HRPC is in an exciting period with many breakthroughs happening. Remember, each new drug being tested offers the promise of a new treatment option for HRPC patients.
FDA-Approved Therapies for HRPC
Xgeva, Zometa, and Other Bone-Protecting Drugs
In this chapter, we’ll consider the drugs Xgeva and Zometa. Recent phase-3 comparison clinical trials indicate that Xgeva appears to work better than Zometa for most patients to protect bones and reduce skeletal-related events (SREs). If a doctor recommends these drugs, a patient would receive one or the other (usually Xgeva). Neither drug has been shown to improve survival in HRPC patients (although this is currently being studied), but they can have a large impact on improving quality of life.
We’ll also briefly discuss other drugs approved to reduce bone pain from metastatic disease. Those drugs, radiopharmaceutical (IV drugs that give off radiation to specific metastatic bone sites), include samarium and strontium. A newer radiopharmaceutical, Alpharadin, may soon replace samarium and strontium for most patients (see chapter nine).
Question: What is an SRE?
Answer: Problems associated with cancer going into the bone are collectively referred to as skeletal-related events (SREs). There are several SREs caused by metastatic prostate cancer:
Bone fractures These are known as “pathologic bone fractures” of the spine (vertebral area) or non-spine areas (such as hip, leg, or wrist). The most common sites for bone fractures are the hip and upper legs, the spine, wrist, and ribs.
Spinal cord compression If prostate cancer gets into the backbone or spinal cord, it can create pressure and cause nerve damage. The nerves of the spinal cord control all sorts of body operations, so damage to the cord can cause problems such as pain, numbness, muscle weakness, and even bladder control issues.
Radiation to the bone or an IV drug needed to get to the bones When cancer penetrates the bone and causes pain, some patients need radiation delivered to that same site to reduce the bone pain and to potentially stop the tumor site from doing more damage. This is known as spot radiation. Other patients may require radioisotopes (radiopharmaceuticals), drugs given that find those tumor sites, reduce the pain, and potentially stop more damage to the tumor site.
Surgery to the bone If the bones become weak, damaged, or broken, they often need some type of surgery to repair the problem bone site.
Hypercalcemia Another SRE is a high blood level of calcium (hypercalcemia) that can occur with bone loss. However, Xgeva and Zometa do a very good job of preventing this problem. In fact, these drugs are now used in several non–cancer-related emergency situations, including in children when a blood level of calcium becomes high enough that it creates a life-threatening condition.
XGEVA
Also known as Denosumab
How is it taken? injection
Approval status FDA approved
Company Amgen
Advantages It is an injection usually given once every month, or less often in some cases, with a low rate of side effects. It may be usable at any time in men with HRPC to improve bone health and reduce the risk of skeletal-related events (SREs). In a phase-3 study, it beat Zometa in terms of preventing SREs and, perhaps, at reducing the risk of metastatic bone disease.
The catch Calcium (at least 500 mg or more) and vitamin D (at least 400 IU or more) supplements are strongly recommended for patients getting Xgeva. The precise amount to take depends on how much calcium you get from food and the results of a vitamin D blood test. Discuss these supplements with your doctor to determine the right amount for your situation. There seems to be a rare increased risk of osteonecrosis of the jaw (ONJ), similar or even slightly greater to what has been observed with Zometa, and a higher risk of causing low blood calcium (hypocalcemia). Approximately 80 percent of patients with ONJ had a
