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FDA Public Health Advisory
Suspended Marketing of Tysabri (natalizumab)
The issues described in this communication have been addressed in product labeling, please see Drugs@FDA
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FDA is issuing this public health
advisory to inform patients and health care providers about the
suspended marketing of Tysabri (natalizumab) due to two serious
adverse events reported with its use. FDA has received a report from
Biogen Idec, the manufacturer of Tysabri, of one confirmed, fatal
case and one additional case of progressive multifocal
leukoencephalopathy (PML) in patients receiving Tysabri for multiple
sclerosis (MS). Both patients were enrolled in a long-term clinical
trial and had been taking Tysabri for more than two years. There
have been no previous cases of PML reported in patients taking
Tysabri.
Although the relationship between Tysabri and PML is not known at
this time, because of the rare, serious and often fatal nature of
PML, FDA is announcing the following, effective immediately:
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Biogen Idec is voluntarily suspending
marketing of Tysabri.
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Biogen Idec is suspending dosing of Tysabri in clinical trials and is notifying patients and
investigators of the possible association between Tysabri and PML.
Patients being treated with Tysabri
should contact their physician to discuss appropriate alternative
treatments. At this time, there are no specific diagnostic or
therapeutic interventions recommended for patients who have been
taking Tysabri, other than to discontinue its use. Physicians should
evaluate all patients who have received Tysabri and who have signs
or symptoms suggestive of PML. Any suspect cases of PML should be
reported immediately to Biogen Idec or to the FDA MedWatch program,
as described at the end of this advisory. FDA and Biogen Idec will
provide further guidance should additional recommendations be deemed
appropriate.
Discussions between the FDA, Biogen Idec, and scientific experts
have begun in order to assess the potential association between
Tysabri and PML, methods for early diagnosis of PML, and to
determine whether MS patients who may be at particular risk can be
identified. These discussions will be informed by the substantial
amount of patient data from clinical trials expected to be obtained
in the next few months, including specific assessments of patients
who have received Tysabri for evidence of early-stage PML, and will
be used to guide decisions regarding future marketing of Tysabri.
PML is a rare, serious, progressive neurologic disease, usually
occurring in immunosuppressed patients, often resulting in
irreversible neurologic deterioration and death. There is no known
effective treatment for PML, although reversing immune system
suppression may slow or arrest progression of the disease.
Based on information submitted to the FDA this week, neither patient
described above has known risk factors for PML. Both patients
received concomitant Avonex (interferon beta-1a). The use of
interferons, including Avonex, has not been associated with PML. To
further understand the association between Tysabri and the
development of PML, Biogen Idec is reviewing all adverse events in
the clinical trial database for Tysabri to determine if any of these
could possibly represent cases of PML.
Tysabri received accelerated approval in November 2004 for reducing
the frequency of exacerbations in patients with remitting-relapsing
MS, the most common form of this disease, after one year of
treatment. Tysabri when added to Avonex reduced the risk of
exacerbations by 54% compared to Avonex alone. Tysabri by itself
reduced the risk by 66% compared to placebo. These results represent
an important and meaningful benefit for patients with MS. At the
time of approval, approximately 1,100 patients with MS had received
Tysabri for one year or more. Confirmatory studies were required to
be carried out to show continued benefit of the drug after two years
of treatment. The two cases reported here occurred in patients in
the confirmatory studies. No cases of PML were observed during the
clinical trials performed prior to approval of Tysabri.
The FDA will continue to notify health care providers and patients
in a timely fashion as new information becomes available.
The FDA urges health care providers
and patients to report adverse event information to FDA via the
MedWatch program by phone (1-800-FDA-1088), by fax (1-800-FDA-0178),
or by the Internet at
http://www.fda.gov/medwatch/index.html.
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Date created: February 28, 2005, updated July, 2007 |
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