Multiple Sclerosis (MS) drug Tysabri, which was expected to become
the world’s leading treatment for the condition, was pulled
from the market after a patient died from a rare central nervous
system infection.
The patient died from progressive multifocal leukoencephalopathy
(PML), a rare infection of the brain and spinal cord, and another
case was suspected, prompting the drug’s makers, Biogen Idec
and Elan Corp., to stop sales of the drug. They also stopped clinical
trials of Tysabri to treat rheumatoid arthritis and Crohn's disease,
PML occurred in patients who had been taking Tysabri in combination
with Avonex, another MS drug made by Biogen Idec, for two years
or more--the condition was not found in patients taking Tysabri
alone.
The companies plan to re-examine brain scans from patients in former
clinical trials to see if a connection exists between Tysabri and
PML. If no other cases of PML are found, Elan said it hopes that
Tysabri will be back on the market by the third quarter of 2005.
The Food and Drug Administration (FDA) approved Tysabri in November
2004 under an accelerated program the FDA reserves for drugs it
believes will have “extraordinary benefits” to patients.
It’s the first in a class of MS drugs called selective adhesion
molecule, or SAM, inhibitors, and it works by blocking a molecule
known as alpha-4 integrin and preventing inflammatory cells from
working into brain tissue.
However, at least one expert sounded an alarm to the FDA prior
to the drug’s approval. Dr. Lawrence Steinman, a Stanford University
professor and an MS specialist who has developed MS drugs himself,
said he repeatedly warned of the potential for serious immune-system
side effects with Tysabri and drugs like it. The agency’s expedited
approval system has been criticized in the past for rushing drugs
to market before they’ve been thoroughly tested.
The FDA said the drug fit the criteria for accelerated approval,
and the decision was based on clinical trials that showed it reduced
the rate of MS attacks by up to 66 percent. Existing therapies reduced
the frequency by 30 percent to 40 percent.
The recall has had a major impact on the drug’s makers. After
Tysabri, which was expected to generate more than $1 billion in
sales, was withdrawn, Biogen shares went down 43 percent while Elan
shares went down 70 percent. Combined, the two companies lost $16.9
billion in market value.
Further, in the two weeks before the recall, three Biogen executives
sold thousands of company shares for millions of dollars in profits.
Elan execs did not make any sales in the days before the FDA recall
notification.
ABC
News February 28, 2005
Los
Angeles Times March 2, 2005
USA
Today March 1, 2005
| 