U.S. Food and Drug Administration
FDA Consumer magazine
March-April 2002
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The FDA has approved a vest-like device that monitors and treats abnormal heart rhythms in people at risk of dying from sudden cardiac arrest. The device is the first cardioverter defibrillator that can be worn outside the body, rather than implanted in the chest.
The defibrillator detects abnormal heart rhythms by sensing the heart's electrical activity on the surface of the chest. If a life-threatening rhythm is detected, the device delivers an electrical shock to restore normal rhythm.
The device consists of an electrode belt assembly that's worn around the chest underneath clothes. A connected monitor with an alarm is worn in a holster at the waist. The entire device assembly is worn continuously 24 hours a day, except when bathing or showering. Typically once a week, the wearer will need to connect the monitor to an external modem and send the data it has collected over the phone to a physician's computer for review.
Some 289 people at 16 medical centers in the United States and Europe were fitted with the defibrillator vest. They were either awaiting heart transplants or had recently had a heart attack or a coronary bypass operation. The patients wore the vests for an average of 20 hours a day for about three months.
The defibrillator was 71 percent successful in treating sudden cardiac arrest episodes, compared to the 25 percent success for patients calling 911. The most frequent side effect of the device in clinical studies was a temporary skin rash.
Lifecor Inc. of Pittsburgh makes the wearable defibrillator.
A device implanted in the brain to help control some symptoms of advanced Parkinson's disease was approved for an expanded use recently by the FDA.
The device, a deep brain stimulator, made by Medtronic Inc. of Minneapolis, was initially approved by the FDA in 1997 for use in one side of the brain to help control tremors on one side of the body. In January, after review of additional studies conducted by the manufacturer, the FDA approved the device for use in both sides of the brain to help reduce some of the other symptoms of advanced Parkinson's that cannot be adequately controlled with medication.
An estimated 1.5 million Americans have Parkinson's disease, which results in tremors, rigidity, unstable balance (postural instability), slowness, difficulty moving and, in some people, intellectual deterioration.
The device, called the Activa Parkinson's Control System, consists of electrodes that are implanted into the brain and connected by leads (wires) under the skin to a pulse generator implanted in the abdomen or chest. The pulse generator sends electrical pulses to the brain. When the device is implanted in both sides of the brain, two separate systems are used. To turn the stimulator on and off, the patient holds a magnet over the pulse generator.
Medtronic conducted a 12-month study in 160 people who received the Activa system brain implant. For 117 patients whose data were verified against medical records, motor skills improved in nearly half of those who were also taking medication and in about 90 percent of those not taking medication.
Although some people in the study benefited significantly from the Activa system, the study also showed that individual results varied considerably and specific benefit for an individual cannot be predicted.
Nearly all of the study participants experienced one or more adverse events. During the entire study, 7.5 percent had bleeding into the brain, 11 percent had device-related infection, 10 percent had weakness (paresis/asthenia), and 8 percent had paralysis or weakness on one side of the body (hemiplegia/hemiparesis). Some 37 percent of the adverse events, such as breakage of the lead, pain, and infection, were related to the Activa system. Approximately 6 percent of the device-related adverse events were serious and ongoing, including a worsening of motor impairment and other Parkinson's symptoms.
Medtronic has agreed to conduct a three-year post-approval study of the system to assess its long-term results.
A new type of blood thinner that reduces the risk of blood clots following hip and knee surgeries has been approved by the FDA.
Arixtra Injection (fondaparinux sodium) is the first synthetic option available to people undergoing orthopedic surgery for hip fractures and hip and knee replacements. The formation of clots in the deep veins of the legs is common after these surgeries and can lead to serious and potentially fatal consequences, especially if the clots break off and travel to the lungs. Arixtra, which was approved in December 2001, works by inhibiting Factor Xa, a key component in causing blood clots.
All anti-clotting drugs, including Arixtra, can cause serious bleeding. Therefore, people with severely impaired kidney function or those who weigh less than 100 pounds should not use this drug. Elderly people also may be more likely to experience serious bleeding complications.
The FDA is requiring the makers of Arixtra--Sanofi-Synthélabo, Paris, and Organon, of West Orange, N.J.--to include a statement in the product's labeling warning that the drug is not to be used when spinal anesthesia or spinal puncture is performed. There is a risk of blood clots forming in the spine, which can cause permanent paralysis.
The FDA is warning consumers to stop using Lipokinetix, purported to be a dietary supplement for weight loss by Syntrax Innovations Inc., Cape Girardeau, Mo. The warning, issued in November 2001, was prompted by reports to FDA of people who developed liver injury or liver failure while using Lipokinetix.
Lipokinetix contains the ingredients norephedrine, caffeine, yohimbine, diiodothyronine, and sodium usniate. The injuries reported to the FDA occurred in people between 20 and 32 years old. Liver injury developed between two weeks and three months after Lipokinetix use was started.
The FDA urges consumers to stop using Lipokinetix and to consult their physician if they are experiencing symptoms possibly associated with the product, particularly nausea, weakness or fatigue, abdominal pain, or any change in skin color. Report adverse effects from Lipokinetix or any other drug or dietary supplement products to the FDA's MedWatch hotline at 1-800-FDA-1088 or via the Internet at www.fda.gov/medwatch/how.htm.
Serious Product Problem? Report ItHealth professionals can report serious adverse reactions or other product problems to the FDA's MedWatch program by:
The FDA encourages consumers to report through their doctors, but if they prefer, they may submit the MedWatch form themselves. |
The FDA has approved Tracleer (bosentan) tablets to improve the aerobic abilities of people with a rare but fatal lung disorder called pulmonary arterial hypertension (PAH).
PAH is defined as abnormally high blood pressure in the arteries between the heart and lungs. The condition reduces the ability to exert oneself physically without becoming short of breath. PAH significantly shortens the life span because it leads to heart failure.
Tracleer blocks the action of endothelin, a substance made in the body that narrows blood vessels and elevates blood pressure. In two clinical trials involving 245 people, treatment with Tracleer significantly increased the six-minute walking distance of those taking the drug, compared to those taking an inactive pill (placebo). In both studies, Tracleer or the placebo was given in addition to any other medications that were prescribed.
The use of Tracleer requires attention to two significant risks: liver toxicity and the drug's potential to damage a fetus. To ensure careful monitoring for these risks, Tracleer will only be available through a direct distribution program from the drug's manufacturer, Actelion Pharmaceuticals US Inc. of South San Francisco, Calif.
Tracleer's warning information states that liver enzyme levels must be measured before initiation of treatment with the drug and monthly thereafter to avoid liver injury. To date, the elevation of liver enzymes caused by Tracleer has been resolved without causing permanent liver damage.
Because of its potential to cause birth defects, Tracleer must not be prescribed to pregnant women. Female patients of childbearing age must take measures to prevent pregnancy, and monthly pregnancy testing will be required. Oral, injected, and implanted contraceptives may not be reliable because Tracleer may alter a woman's metabolism in a way that reduces their effectiveness. So women who take Tracleer must consult with a gynecologist or other doctor knowledgeable about contraceptives.
Under a November 2001 interagency agreement, the FDA and the Department of Veterans Affairs (VA) will work together to improve the clinical knowledge of the adverse effects of drugs used to treat HIV infection.
The agencies will conduct a study to determine whether the destruction of bone cells due to deficient blood supply--avascular necrosis (AVN)--is linked to the use of certain drugs to treat HIV or is a natural consequence of the infection with the AIDS virus.
The study will focus on cases of suspected AVN registered with the Veterans Health Administration's centralized HIV registry in Palo Alto, Calif., the world's largest clinical database on HIV/AIDS. The FDA will develop Web-based software that will allow VA clinicians to efficiently and confidentially supplement information on suspect cases with radiological data and other clinical details necessary to confirm the diagnosis of AVN.
Depending on the outcome, the FDA could require certain antiviral drugs to undergo labeling changes and require manufacturers to inform prescribers of the new information.
A drug to treat hereditary tyrosinemia type I (HT-1), a rare disease causing progressive liver failure and liver cancer in young children, was approved by the FDA.
The drug, Orfadin (nitisinone) capsules, is an orphan drug. Orphan products are developed to treat rare diseases or conditions that affect less than 200,000 people in the United States. The Orphan Drug Act provides a seven-year period of exclusive marketing to the first sponsor who obtains marketing approval for a designated orphan drug.
Fewer than 100 children in the United States are affected by HT-1. Children with HT-1 rarely survive into their 20s without a liver transplant. However, for children treated early enough with Orfadin, liver failure and liver cancer occur at much-reduced rates.
Orfadin was studied in more than 180 children with a median age of 9 months at the start of therapy. When the drug was combined with a restricted diet, the four-year survival rate of children under 2 months of age at the time of diagnosis was 88 percent. Historical data for children treated with dietary restrictions alone indicates a survival rate of 29 percent for the same time period.
Orfadin must be combined with a diet restricted in the amino acids tyrosine and phenylalanine. The most common side effects of the drug were related to high tyrosine levels due to deviation from the restricted diet, as well as rare cases of mild reductions in platelet and white blood cell counts. High tyrosine levels may be toxic to eyes, skin and the nervous system.
Orfadin should be prescribed by physicians experienced in treating HT-1. Doses must be adjusted and monitored for each child according to specific tests.
Orfadin is a product of Swedish Orphan International AB, of Stockholm, Sweden, and is distributed in the United States by Rare Disease Therapeutics Inc., of Nashville, Tenn.
The FDA has approved the use of a new cancer drug to treat a relatively uncommon tumor that develops in the stomach or intestinal tract and spreads within the abdomen or pelvis.
Gleevec (imatinib mesylate) received the go-ahead in February to treat gastrointestinal stromal tumor (GIST). The drug was first approved by the FDA in May 2001 to treat chronic myeloid leukemia (CML), a form of cancer that affects blood cells.
The drug was cleared for this new indication after studies showed a modest reduction in tumor size.
The latest approval came under the orphan drug regulations and the accelerated approval program. The orphan drug program encourages development of drugs for rare diseases affecting fewer than 200,000 people. Accelerated approval allows drugs to reach patients earlier than normal.
Gleevec works by blocking enzymes that play a role in cancer growth. In GIST, Gleevec blocks a different abnormal enzyme found in the tumor cells than the one associated with CML. As these abnormal enzymes are largely confined to cancer cells, there is relatively little damage to normal cells while cancer cells are killed.
Common side effects reported with Gleevec include fluid retention, nausea, vomiting, diarrhea, skin rash, muscle cramps, liver toxicity, and lower blood cell counts. Side effects are generally mild to moderate in severity.
Gleevec is manufactured by Novartis AG for Novartis Pharmaceuticals Corp., East Hanover, N.J.
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