Radium Ra 223 Dichloride
FDA Drug Information • Also known as: Xofigo
- Brand Names
- Xofigo
- Route
- INTRAVENOUS
- Dosage Form
- INJECTION
- Product Type
- HUMAN PRESCRIPTION DRUG
Description
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. Radium is present in the solution as a free divalent cation. Each vial contains 6 mL of solution (6,600 kBq (178 microcurie) radium-223 dichloride at the reference date). The inactive ingredients are 6.3 mg/mL sodium chloride USP (tonicity agent), 7.2 mg/mL sodium citrate USP (for pH adjustment), 0.2 mg/mL hydrochloric acid USP (for pH adjustment), and water for injection USP. The molecular weight of radium-223 dichloride, 223 RaCl 2, is 293.9 g/mol. Radium-223 has a half-life of 11.4 days. The specific activity of radium-223 is 1.9 MBq (51.4 microcurie)/ng. The six-stage-decay of radium-223 to stable lead-207 occurs via short-lived daughters, and is accompanied predominantly by alpha emissions. There are also beta and gamma emissions with different energies and emission probabilities. The fraction of energy emitted from radium-223 and its daughters as alpha-particles is 95.3% (energy range of 5 - 7.5 MeV). The fraction emitted as beta-particles is 3.6% (average energies are 0.445 MeV and 0.492 MeV), and the fraction emitted as gamma-radiation is 1.1% (energy range of 0.01 - 1.27 MeV).
What Is Radium Ra 223 Dichloride Used For?
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 )
Dosage and Administration
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 1.49 microcurie/kg body weight Radioactivity concentration of the product (1,100 kBq/mL; 30 microcurie/mL) at the reference date Decay correction factor to correct for physical decay of radium-223. The total volume to be administered to a patient is calculated as follows: Volume to be administered (mL) = Body weight in kg × 55 kBq/kg body weight Decay factor × 1,100 kBq/mL or Volume to be administered (mL) = Body weight in kg × 1.49 microcurie/kg body weight Decay factor × 30 microcurie/mL Table 1: Decay Correction Factor Table Days from Reference Date Decay Factor Days from Reference Date Decay Factor -14 2.296 0 0.982 -13 2.161 1 0.925 -12 2.034 2 0.870 -11 1.914 3 0.819 -10 1.802 4 0.771 -9 1.696 5 0.725 -8 1.596 6 0.683 -7 1.502 7 0.643 -6 1.414 8 0.605 -5 1.330 9 0.569 -4 1.252 10 0.536 -3 1.178 11 0.504 -2 1.109 12 0.475 -1 1.044 13 0.447 14 0.420 The Decay Correction Factor Table is corrected to 12 noon Central Standard Time (CST). To determine the decay correction factor, count the number of days before or after the reference date. The Decay Correction Factor Table includes a correction to account for the 7 hour time difference between 12 noon Central European Time (CET) at the site of manufacture and 12 noon US CST, which is 7 hours earlier than CET. Immediately before and after administration, the net patient dose of administered Xofigo should be determined by measurement in an appropriate radioisotope dose calibrator that has been calibrated with a National Institute of Standards and Technology (NIST) traceable radium-223 standard (available upon request from Bayer) and corrected for decay using the date and time of calibration. The dose calibrator must be calibrated with nationally recognized standards, carried out at the time of commissioning, after any maintenance procedure that could affect the dosimetry and at intervals not to exceed one year. 2.2 Administration Administer Xofigo by slow intravenous injection over 1 minute. Flush the intravenous access line or cannula with isotonic saline before and after injection of Xofigo. Discard any unused portion, if applicable [see Dosage and Administration (2.3)]. 2.3 Instructions for Use/Handling General warning Xofigo (an alpha particle-emitting pharmaceutical) should be received, used and administered only by authorized persons in designated clinical settings. The receipt, storage, use, transfer and disposal of Xofigo are subject to the regulations and/or appropriate...Side Effects (Adverse Reactions)
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. at 1-888-842-2937 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. In the randomized clinical trial in patients with metastatic castration-resistant prostate cancer with bone metastases, 600 patients received intravenous injections of 55 kBq/kg (1.49 microcurie/kg) of Xofigo and best standard of care and 301 patients received placebo and best standard of care once every 4 weeks for up to 6 injections. Prior to randomization, 58% and 57% of patients had received docetaxel in the Xofigo and placebo arms, respectively. The median duration of treatment was 20 weeks (6 cycles) for Xofigo and 18 weeks (5 cycles) for placebo. The most common adverse reactions (≥ 10%) in patients receiving Xofigo were nausea, diarrhea, vomiting, and peripheral edema (Table 3). Grade 3 and 4 adverse events were reported among 57% of Xofigo-treated patients and 63% of placebo-treated patients. The most common hematologic laboratory abnormalities in Xofigo-treated patients (≥ 10%) were anemia, lymphocytopenia, leukopenia, thrombocytopenia, and neutropenia (Table 4). Treatment discontinuations due to adverse events occurred in 17% of patients who received Xofigo and 21% of patients who received placebo. The most common hematologic laboratory abnormalities leading to discontinuation for Xofigo were anemia (2%) and thrombocytopenia (2%). Table 3 shows adverse reactions occurring in ≥ 2% of patients and for which the incidence for Xofigo exceeds the incidence for placebo. Table 3: Adverse Reactions in the Randomized Trial System/Organ Class Preferred Term Xofigo (n=600) Placebo (n=301) Grades 1-4 % Grades 3-4 % Grades 1-4 % Grades 3-4 % Blood and lymphatic system disorders Pancytopenia 2 1 0 0 Gastrointestinal disorders Nausea 36 2 35 2 Diarrhea 25 2 15 2 Vomiting 19 2 14 2 General disorders and administration site conditions Peripheral edema 13 2 10 1 Renal and urinary disorders Renal failure and impairment 3 1 1 1 Laboratory Abnormalities Table 4 shows hematologic laboratory abnormalities occurring in > 10% of patients and for which the incidence for Xofigo exceeds the incidence for placebo. Table 4: Hematologic Laboratory Abnormalities Hematologic Laboratory Abnormalities Xofigo (n=600) Placebo (n=301) Grades 1-4 % Grades 3-4 % Grades 1-4 % Grades 3-4 % Anemia 93 6 88 6 Lymphocytopenia 72 20 53 7 Leukopenia 35 3 10 <1 Thrombocytopenia 31 3 22 <1 Neutropenia 18 2 5 <1 Laboratory values were obtained at baseline and prior to each 4-week cycle. As an adverse reaction, grade 3-4 thrombocytopenia was reported in 6% of patients on Xofigo and in 2% of patients on placebo. Among patients who received Xofigo, the laboratory abnormality grade 3-4 thrombocytopenia occurred in 1% of docetaxel naïve patients and in 4% of patients who had received prior docetaxel. Grade 3-4 neutropenia occurred in 1% of docetaxel naïve patients and in 3% of patients who have received prior docetaxel. Fluid Status Dehydration occurred in 3% of patients on Xofigo and 1% of patients on placebo. Xofigo increases adverse reactions such as diarrhea, nausea, and vomiting which may result in dehydration. Monitor patients’ oral intake and fluid status carefully...Drug 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.
Contraindications
4 CONTRAINDICATIONS None. None.
Pregnancy and Breastfeeding
8.1 Pregnancy Risk Summary The safety and efficacy of Xofigo have not been established in females. Based on mechanism of action, Xofigo can cause fetal harm when administered to a pregnant female [see Clinical Pharmacology ( 12.1 )] . While there are no human or animal data on the use of Xofigo in pregnancy, maternal use of a radioactive therapeutic agent could affect development of a fetus. Advise pregnant females and females of reproductive potential of the potential risk to a fetus.
Overdosage
10 OVERDOSAGE There have been no reports of inadvertent overdosing of Xofigo during clinical studies. There is no specific antidote. In the event of an inadvertent overdose of Xofigo, utilize general supportive measures, including monitoring for potential hematological and gastrointestinal toxicity, and consider using medical countermeasures such as aluminum hydroxide, barium sulfate, calcium carbonate, calcium gluconate, calcium phosphate, or sodium alginate. 1 Single Xofigo doses up to 276 kBq (7.46 microcurie) per kg body weight were evaluated in a phase 1 clinical trial and no dose-limiting toxicities were observed.
How Supplied
16 HOW SUPPLIED/STORAGE AND HANDLING Xofigo (radium Ra 223 dichloride injection) is supplied in single-dose vials containing 6 mL of clear, colorless solution at a concentration of 1,100 kBq/mL (30 microcurie/mL) with a total radioactivity of 6,600 kBq/vial (178 microcurie/vial) at the reference date (NDC 50419-208-01). Store at room temperature, below 40° C (104° F). Store Xofigo in the original container or equivalent radiation shielding. This preparation is approved for use by persons under license by the Nuclear Regulatory Commission or the relevant regulatory authority of an Agreement State. Follow procedures for proper handling and disposal of radioactive pharmaceuticals [see Dosage and Administration ( 2.3 )].
About This Information
This drug information is sourced from FDA-approved labeling via the openFDA database. It is intended for educational and reference purposes only. This is not medical advice. Always consult your healthcare provider before making decisions about medication. Drug information may be updated by the FDA; check with your pharmacist for the most current information.
What are side effects?
Side effects are unwanted reactions that can occur when taking a medication. They range from mild (headache, nausea) to severe (allergic reactions, organ damage). Not everyone experiences side effects, and severity varies. Report any concerning side effects to your doctor.
What are drug interactions?
Drug interactions occur when a medication is affected by another drug, food, or supplement. Interactions can make medications less effective or cause dangerous side effects. Always tell your doctor about all medications and supplements you take.