Overview
11 DESCRIPTION Radium Ra 223 dichloride, an alpha particle-emitting pharmaceutical, is a radiotherapeutic drug. Xofigo is supplied as a clear, colorless, isotonic, and sterile solution to be administered intravenously with pH between 6 and 8. Each milliliter of solution contains 1,100 kBq radium-223 dichloride (30 microcurie), corresponding to 0.58 ng radium-223, at the reference date.
Mechanism of Action
12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action The active moiety of Xofigo 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 (see Table 2). The high linear energy transfer of alpha particles (80 keV/micrometer) leads to a high frequency of double-strand DNA breaks in adjacent cells including tumor cells, osteoblasts and osteoclasts, 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. 12.
Indications
- 1 INDICATIONS AND USAGE Xofigo is indicated for the treatment of patients with castration-resistant prostate cancer, symptomatic bone metastases and no known visceral metastatic disease. Xofigo is an alpha particle-emitting radioactive therapeutic agent indicated for the treatment of patients with castration-resistant prostate cancer, symptomatic bone metastases and no known visceral metastatic disease. ( 1 )
Common Doses
- Refer to label
Dosage
2 DOSAGE AND ADMINISTRATION The dose regimen of Xofigo is 55 kBq (1.49 microcurie) per kg body weight, given at 4 week intervals for 6 injections. ( 2.1 ) 2.1 Recommended Dosage The dose regimen of Xofigo is 55 kBq (1.49 microcurie) per kg body weight, given at 4 week intervals for 6 injections. Safety and efficacy beyond 6 injections with Xofigo have not been studied. The volume to be administered to a given patient should be calculated using the: • Patient’s body weight (kg) • Dosage level 55 kBq/kg body weight or 1.
Contraindications
- 4 CONTRAINDICATIONS None. None.
Side Effects
- 6 ADVERSE REACTIONS The following serious adverse reactions are discussed in greater detail in another section of the label: • Bone Marrow Suppression [see Warnings and Precautions ( 5.1 )] The most common adverse drug reactions (≥ 10%) in patients receiving Xofigo were nausea, diarrhea, vomiting, and peripheral edema. The most common hematologic laboratory abnormalities (≥ 10%) were anemia, lymphocytopenia, leukopenia, thrombocytopenia, and neutropenia. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Bayer HealthCare Pharmaceuticals Inc.
Interactions
- 7 DRUG INTERACTIONS No formal clinical drug interaction studies have been performed. Subgroup analyses indicated that the concurrent use of bisphosphonates or calcium channel blockers did not affect the safety and efficacy of Xofigo in the randomized clinical trial.