QUADRAMET® is indicated for relief of pain in patients with confirmed osteoblastic metastatic bone lesions that enhance on radionuclide bone scan.
QUADRAMET® is contraindicated in patients who have known hypersensitivity to EDTMP or similar phosphonate compounds.
QUADRAMET® causes bone marrow suppression. In clinical trials, white blood cell counts and platelet counts decreased to a nadir of approximately 40% to 50% of baseline in 123 (95%) of patients within 3 to 5 weeks after QUADRAMET® , and tended to return to pretreatment levels by 8 weeks. The grade of marrow toxicity is shown in Table 5 below.
|Toxicity Grade *||PlaceboN=85||1.0 mCi/kgN=185||PlaceboN=85||1.0 mCi/kgN=184||PlaceboN=85||1.0 mCi/kgN-185|
|0-2||78 (92%)||162 (88%)||85 (100%)||169 (92%)||85 (100%)||173 (94%)|
|3||6 (7%)||20 (11%)||0 (0%)||15 (8%)||0 (0%)||10 (5%)|
|4||1 (1%)||3 (2%)||0 (0%)||0 (0%)||0 (0%)||2 (1%)|
Before QUADRAMET® is administered, consideration should be given to the patient’s current clinical and hematologic status and bone marrow response history to treatment with myelotoxic agents. Metastatic prostate and other cancers can be associated with disseminated intravascular coagulation (DIC); caution should be exercised in treating cancer patients whose platelet counts are falling or who have other clinical or laboratory findings suggesting DIC. Because of the unknown potential for additive effects on bone marrow, QUADRAMET® should not be given concurrently with chemotherapy or external beam radiation therapy unless the clinical benefits outweigh the risks. Use of QUADRAMET® in patients with evidence of compromised bone marrow reserve from previous therapy or disease involvement is not recommended unless the potential benefits of the treatment outweigh the risks. Blood counts should be monitored weekly for at least 8 weeks, or until recovery of adequate bone marrow function.
As with other radiopharmaceutical drugs, QUADRAMET® can cause fetal harm when administered to a pregnant woman. Adequate and well controlled studies have not been conducted in animals or pregnant women. Women of child-bearing age should have a negative pregnancy test before administration of QUADRAMET®. If this drug is used during pregnancy, or if a patient becomes pregnant after taking this drug, the patient should be apprised of the potential hazard to the fetus. Women of childbearing potential should be advised to avoid becoming pregnant soon after receiving QUADRAMET®. Men and women patients should be advised to use an effective method of contraception after the administration of QUADRAMET®.
The vial stopper contains dry natural rubber latex and may cause allergic reactions in providers or patients who are sensitive to latex
EDTMP is a chelating agent. Although the chelating effects have not been evaluated thoroughly in humans, dogs that received non-radioactive samarium EDTMP (6 times the human dose based on body weight, 3 times based on surface area) developed a variety of electrocardiographic (ECG) changes (with or without the presence of hypocalcemia). The causal relationship between the hypocalcemia and ECG changes has not been studied. Whether QUADRAMET® causes electrocardiographic changes or arrhythmias in humans has not been studied. Caution and appropriate monitoring should be given when administering QUADRAMET® to patients (See Laboratory Tests).
Because concomitant hydration is recommended to promote the urinary excretion of QUADRAMET® , appropriate monitoring and consideration of additional supportive treatment should be used in patients with a history of congestive heart failure or renal impairment.
Renal Impairment: Because approximately one third of Samarium Sm-153 EDTMP is excreted in the urine, clearance may be reduced in patients with renal impairment; it is not known if dose adjustment is needed.
This drug should be used with caution in patients with compromised bone marrow reserves. See Warnings.
Spinal cord compression frequently occurs in patients with known metastases to the cervical, thoracic or lumbar spine. In clinical studies of QUADRAMET® , spinal cord compression was reported in 7% of patients who received placebo and in 8.3% of patients who received 1.0 mCi/kg QUADRAMET®. QUADRAMET® is not indicated for treatment of spinal cord compression. QUADRAMET® administration for pain relief of metastatic bone cancer does not prevent the development of spinal cord compression. When there is a clinical suspicion of spinal cord compression, appropriate diagnostic and therapeutic measures must be taken immediately to avoid permanent disability.
Radiopharmaceutical agents should be used only by physicians who are qualified by training and experience in the safe use and handling of radionuclides and whose experience and training have been approved by the appropriate government agency authorized to license the use of radionuclides.
QUADRAMET® , like other radioactive drugs, must be handled with care, and appropriate safety measures must be taken to minimize radiation exposure of clinical personnel and others in the patient environment.
Special precautions, such as bladder catheterization, should be taken with incontinent patients to minimize the risk of radioactive contamination of clothing, bed linen, and the patient’s environment. Urinary excretion of radioactivity occurs over about 12 hours (with 35% occurring during the first 6 hours). Studies have not been done on the use of QUADRAMET® in patients with renal impairment.
Patients who receive QUADRAMET® should be advised that for several hours following administration, radioactivity will be present in excreted urine. To help protect themselves and others in their environment, precautions need to be taken for 12 hours following administration. Whenever possible, a toilet should be used, rather than a urinal, and the toilet should be flushed several times after each use. Spilled urine should be cleaned up completely and patients should wash their hands thoroughly. If blood or urine gets onto clothing, the clothing should be washed separately, or stored for 1-2 weeks to allow for decay of the Sm-153.
Some patients have reported a transient increase in bone pain shortly after injection (flare reaction). This is usually mild and self-limiting and occurs within 72 hours of injection. Such reactions are usually responsive to analgesics.
Patients who respond to QUADRAMET® might begin to notice the onset of pain relief one week after QUADRAMET®. Maximal pain relief generally occurs at 3-4 weeks after injection of QUADRAMET®. Patients who experience a reduction in pain may be encouraged to decrease their use of opioid analgesics.
Because of the potential for bone marrow suppression, beginning 2 weeks after QUADRAMET® administration, blood counts should be monitored weekly for at least 8 weeks, or until recovery of adequate bone marrow function.
In a subset of 31 patients who had serum calcium monitored during the first 2 hours after QUADRAMET® infusion, a clear pattern of calcium change was not identified. However, 10 (32%) patients had at least one serum calcium level that was below normal (7.16 to 8.28). The extent to which samarium-153-EDTMP is related to this hypocalcemia is not known. Caution should be exercised when administering QUADRAMET® to patients at risk for developing hypocalcemia.
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