RN NEWS WATCH
CA Breakthrough Allows For Highly Targeted Treatment
The FDA has approved the first radioimmunotherapy, a biotechnological breakthrough that couples a radioactive isotope to a monoclonal antibody that can target a specific type of malignant cell. The new treatment, Zevalin, consists of the monoclonal antibody ibritumomab tiuxetan linked to the radioisotope yttrium-90. It is approved for treating low-grade, follicular, or transformed B-cell non-Hodgkin's lymphoma (NHL) in patients who have relapsed or who haven't responded to standard chemotherapy or treatment with the monoclonal antibody rituximab (Rituxan).
The Zevalin regimen has two stages: Patients first receive rituximab (which, in effect, helps prepare the targeted sites) followed by a test dose of Zevalin linked to a low-radiation isotope. If the test dose shows the tumors are properly targeted, the patient receives a second infusion of rituximab seven to nine days later followed by Zevalin linked with the radioisotope yttrium-90.
In a study of NHL patients not responding to chemotherapy, 74% responded to the Zevalin regimen, with 15% achieving remission. In a study comparing the Zevalin regimen to rituximab alone, the overall response rates were 80% vs. 56%, respectively.
Prolonged and severe cytopenias occurred in the majority of patients receiving yttrium-90 Zevalin. Life-threatening infection occurred in 2%, and GI hemorrhage in 1%. Fatal infusion reactions have occurred within 24 hours of rituximab infusions.
U.S. Food and Drug Administration. "FDA approves first radiopharmaceutical product to treat non-Hodgkin's lymphoma." 2002. www.fda.gov/bbs/topics/answers/2002/ans01138.html (26 Feb. 2002).
Based on a news release by IDEC Pharmaceuticals Corporation, February 19, 2002. "Zevalin therapeutic regimen receives FDA marketing approval; first radioimmunotherapy approved by FDA." www.idec pharm.com/site/index.htm (27 Feb. 2002).
Gleevec Approved For Patients With GI Stromal Cancer
Imatinib mesylate (Gleevec), a drug introduced last May for chronic myeloid leukemia, received accelerated FDA approval for treating inoperable and metastatic gastrointestinal stromal tumor (GIST). The cancer typically emerges within the GI tract and metastasizes within the abdomen or pelvis.
Imatinib was studied in 147 patients with inoperable or metastatic GIST. While no patient had complete remission, 38% had a partial response (tumor size reduced by 50% or more).
The duration of response is still under study. The most common adverse events were edema, nausea, vomiting, diarrhea, muscle cramps, liver toxicity, rash, and reduced blood cell counts. Therapy was discontinued in six patients because of adverse events. Seven patients required red blood cell transfusions because of GI or intratumoral bleeding.
U.S. Food and Drug Administration. "FDA approves Gleevec to treat gastrointestinal stromal cancer." 2002. www.fda.gov/bbs/topics/answers/2002/ans01134.html (11 Feb. 2002).
Black Box Warning Added To Antidepressant's Labeling
Revised labeling and patient information have been issued for the antidepressant nefazodone (Serzone) to warn of rare cases of liver failure leading to transplant and/or death. The rate is estimated, conservatively, to be three to four times higher than the average rate of liver failure in the general population. Liver injury from nefazodone has been reported to occur within two to 24 weeks of starting treatment.
The "Black Box warning" now advises providers not to start the drug in patients with active liver disease or elevated baseline serum transaminases. It also advises them to stop (and not restart) it in patients who develop signs or symptoms suggesting liver failure, such as increases in serum AST, or serum ALT levels three or more times higher than the upper normal limit. Patients should call their healthcare provider immediately if they develop jaundice, unusually dark urine, anorexia, nausea, abdominal pain, malaise, or other symptoms of liver problems. Periodic liver function testing is recommended.
New Anemia Drug For Use In Chronic Renal Failure
Darbepoetin alfa (Aranesp) has been approved for the treatment of anemia associated with chronic renal failurewhether patients are on dialysis or not. The new drug has a half-life that's about three times longer than the existing treatment, epoetin alfa (Epogen, Procrit). As a result, darbepoetin should be given less frequently. Its recommended starting dose is one injection (0.45 mcg/kg) per week, but patients who've been receiving epoetin once a week should be given darbepoetin once every two weeks.
Patients receiving either treatment need to be carefully monitored because, in studies, very serious adverse eventsincluding cardiac arrest, neurologic events, and vascular thrombosis/ischemia/infarctionwere associated with increases in hemoglobin greater than approximately 1.0 gm/dL during any two-week period.
The most common adverse effects with darbepoetin are infection, hypertension, hypotension, myalgia, headache, and diarrhea. Monitor patients also for rare, but potentially serious allergic reactions, including skin rash and urticaria. The drug shouldn't be used in patients with uncontrolled hypertension.
Based on a news release by Amgen, September 18, 2001. "FDA approves Amgen's Aranesp for anemia associated with chronic renal failure." www.amgen.com/news/news01/pressRelease010918.html (21 Sept. 2001).
A Woman's Pain, Not Dilation, Should Decide Epidural Timing
The American College of Obstetricians and Gynecologists and the American Society of Anesthesiologists jointly issued a position statement reaffirming that, in the absence of a contraindication, epidural analgesia should be given during any stage of labor if a woman requests it.
Some hospitals delay an epidural until a women reaches 4 5 cm of dilation because studies indicate that giving one early in labor increases the need for cesarean delivery. The two organizations support delaying it "when feasible," but say a woman's request for relief of severe labor pain should be the deciding factor on when to give the epidural.
American College of Obstetricians and Gynecologists. "ACOG supports epidural pain relief on demand." 2002. www.acog.org/from_home/publications/press_releases/nr01-31-02-1.htm (1 Feb. 2002).
Will This Arthritis Drug Interfere With Aspirin?
Q A 57-year-old patient had his first MI about one year ago. His cardiologist prescribes 81 mg of aspirin once daily as prophylaxis against another MI. The patient is already taking 400 mg tid of ibuprofen (Advil, Motrin) for his severe arthritis pain, and the doctor says he should continue with it. Is there a risk of interaction?
A Yes. In a recent study published in the New England Journal of Medicine, ibuprofen was found to reduce the antiplatelet activity by which aspirin protects against a second heart attack.
The patient should be switched to an arthritis medication that will treat his severe pain without limiting aspirin's prophylactic efficacy. Acetaminophen, the COX-2 inhibitor rofecoxib (Vioxx), and diclofenac (Voltaren) were also used in the study and didn't interfere with aspirin. COX-2 inhibitors, which include celecoxib (Celebrex), may not be a first choice for this patient, however, since they are currently being studied for potential cardiovascular effects. (See "Pain Clinic" in the July 2001 issue of RN.)
Source: Catella-Lawson, F., Reilly, M. P., et al. (2001). Cyclooxygenase inhibitors and the antiplatelet effects of aspirin. N Engl J Med, 345(25), 1809.
LINDA M. PORTERFIELD, RN, PhD, is a clinical pharmacologist and director of
cardiovascular research at Arrhythmia Consultants in Memphis. She works with
her husband, James Porterfield, MD, FACC, who is a cardiologist and electrophysiologist.
Drug Update. RN 2002;4:89.
Published in RN Magazine.
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