Generic Name: Radium Ra 223 dichloride (RAY-dee-um Ra 223 dye-KLOR-ide)
Trade Name: Xofigo®
For which conditions is this drug approved? Radium Ra 223 dichloride is indicated for the treatment of patients with castration-resistant prostate cancer, symptomatic bone metastases, and no known visceral metastatic disease.
What is the mechanism of action? The active component of radium Ra 223 dichloride is the alpha particle-emitting isotope radium-223 (as radium Ra 223 dichloride), which mimics calcium and forms complexes with the bone mineral hydroxyapatite at areas of increased bone turnover, such as bone metastases The high linear energy transfer of alpha emitters (80 keV/micrometer) leads to a high frequency of double-strand DNA breaks in adjacent cells, resulting in an anti-tumor effect on bone metastases. The alpha particle range from radium-223 dichloride is less than 100 micrometers (less than 10 cell diameters), which limits damage to the surrounding normal tissue.
How is radium Ra 223 dichloride typically given (administered)? Radium Ra 223 dichloride is administered by slow intravenous injection over 1 minute. Dosage is determined by body weight (50 kBq [1.35 microcurie] per kg body weight) and given at four-week intervals for six injections. Safety and efficacy beyond six injections have not been studied.
How are patients typically monitored? Patients will usually have scheduled meetings with their healthcare provider while they are being treated with radium Ra 223 dichloride. Typically, blood will be drawn to check levels of blood cells and to monitor functions of some organ systems, such as the kidneys or liver. Patients may also undergo physical examinations, scans or other measures to assess side effects and response to therapy.
In addition, patients will have blood counts measured prior to treatment initiation and before every dose of radium Ra 223 dichloride. Physicians are advised to discontinue treatment if hematologic values do not recover within six to eights weeks after treatment. Patients with compromised bone marrow reserve should be monitored closely, and radium Ra 223 dichloride should be discontinued in patients who experience life-threatening complications despite supportive care measures.
What are the common (occur in 30% or more of patients) side effects of treatment with radium Ra 223 dichloride?
What are the less common (occur in 10% to 29% of patients) side effects of treatment with radium Ra 223 dichloride?
This is not a complete list of side effects. Some patients may experience other side effects that are not listed here. Patients may wish to discuss with their physician the other less common side effects of this drug, some of which may be serious.
Some side effects may require medical attention. Other side effects do not require medical attention and may go away during treatment. Patients should check with their physician about any side effects that continue or are bothersome.
What can patients do to help alleviate or prevent discomfort and side effects?
Are there any special precautions patients should be aware of before starting treatment?
When should patients notify their physician?
What is a package insert? A package insert is required by the FDA and contains a summary of the essential scientific information needed for the safe and effective use of the drug for healthcare providers and consumers. A package insert typically includes information regarding specific indications, administration schedules, dosing, side effects, contraindications, results from some clinical trials, chemical structure, pharmacokinetics and metabolism of the specific drug. By carefully reviewing the package insert, you will get the most complete and current information about how to safely use this drug. If you do not have the package insert for the drug you are using, your pharmacist or physician may be able to provide you with a copy.