Tysabri Is No Blockbuster
NEW YORK - Shares of Biogen Idec and Elan soared on Tuesday as the companies said they had completed part of a safety review of their multiple sclerosis drug Tysabri--a medicine that has been demanded by some patients since it was pulled by the companies in February.
But some doctors and analysts still say it is important to be cautious about the meaning of the safety review--especially since scientists are still combing through data testing Tysabri in Crohn's disease, a gastrointestinal disorder, and rheumatoid arthritis.
Biogen (nasdaq: BGEN - news - people ) and Elan (nyse: ELN - news - people ) have finished the safety review of the drug they began when they pulled it from the market on Feb. 28, after it was linked to a rare brain disorder. They've found no new cases of progressive multifocal leukoencephalopathy. In all, they say, there have been three confirmed cases of PML in Tysabri patients, two of them in subjects with multiple sclerosis and one in a subject with Crohn's disease. In all, 2,000 multiple sclerosis patients were included in the review.
"It's good news that there are no new cases," says Igor J. Koralnik, director of the HIV/Neurology Center at Harvard's Beth Israel Deaconess Medical Center and an expert on PML. "But it's not surprising because the medicine had been stopped."
As a scientist and a physician, Koralnik says, he would like to see all the data before drawing any conclusions about Tysabri's risks.
Two cases of PML that were reported in the press were not confirmed in the final review. Says Alex Hittle, an analyst at A.G. Edwards: "It's really a case of 'no news is good news.'"
Especially important is the fact that all three patients who had contracted PML were on other drugs aside from Tysabri. PML seems to occur when a dormant virus--called the JC virus--takes advantage of a weakened immune system. Tysabri is linked to the PML cases, but the MS patients were also taking Avonex, another Biogen drug. The PML patient with Crohn's had taken other drugs that suppress the immune system.
"I think the odds of it getting back to market are looking better and better," says Hittle. "It seems that it's a side effect that's associated with some additional impairment to the immune system," he says.However, earlier this year, many analysts expected Tysabri would take over the MS market, effectively sidelining competition from Teva (nasdaq: TEVA - news - people ) and Serono (nyse: SRA - news - people ). That, Hittle says, is unlikely to happen. The PML issue could make it, "a real medicine of last resort."
Biogen and Elan say that they are taking preliminary steps to restart clinical trials of Tysabri in MS, which could help further define the drug's benefits and risks. Executives on a conference call were optimistic that Tysabri might return to the market for some patients. "We're encouraged that it will be coming back to the market," said James Mullen, chief executive of Biogen Idec.
Despite Mullen's optimism, there is still room for doubt on Tysabri. On a conference call with analysts at Sanford C. Bernstein last week, Daniel Wynn, a multiple sclerosis investigator, said that most patients being evaluated for safety were not given spinal taps--the most conclusive test for PML and the virus that causes it. Based on today's conference call with the companies, Wynn appears to have been correct.
"I think they are being very cautious on their language," says Geoffrey Porges, the biotech analyst at Bernstein. "The companies have said that there are 'no new confirmed cases', not 'no new potential cases.'"
Porges says he would still like to know how many patients who did not have spinal taps had suspected cases of PML. "I think we are still several steps away from a final decision," Porges says, "but this is now set up for a showdown with the regulatory agencies with patients and the companies on one side and safety oversight and caution on the other side."
http://www.forbes.com/home_europe/technology/2005/08/09/drugs-biogen-tysabri-cx_mh_0809tysabri2.html
But some doctors and analysts still say it is important to be cautious about the meaning of the safety review--especially since scientists are still combing through data testing Tysabri in Crohn's disease, a gastrointestinal disorder, and rheumatoid arthritis.
Biogen (nasdaq: BGEN - news - people ) and Elan (nyse: ELN - news - people ) have finished the safety review of the drug they began when they pulled it from the market on Feb. 28, after it was linked to a rare brain disorder. They've found no new cases of progressive multifocal leukoencephalopathy. In all, they say, there have been three confirmed cases of PML in Tysabri patients, two of them in subjects with multiple sclerosis and one in a subject with Crohn's disease. In all, 2,000 multiple sclerosis patients were included in the review.
"It's good news that there are no new cases," says Igor J. Koralnik, director of the HIV/Neurology Center at Harvard's Beth Israel Deaconess Medical Center and an expert on PML. "But it's not surprising because the medicine had been stopped."
As a scientist and a physician, Koralnik says, he would like to see all the data before drawing any conclusions about Tysabri's risks.
Two cases of PML that were reported in the press were not confirmed in the final review. Says Alex Hittle, an analyst at A.G. Edwards: "It's really a case of 'no news is good news.'"
Especially important is the fact that all three patients who had contracted PML were on other drugs aside from Tysabri. PML seems to occur when a dormant virus--called the JC virus--takes advantage of a weakened immune system. Tysabri is linked to the PML cases, but the MS patients were also taking Avonex, another Biogen drug. The PML patient with Crohn's had taken other drugs that suppress the immune system.
"I think the odds of it getting back to market are looking better and better," says Hittle. "It seems that it's a side effect that's associated with some additional impairment to the immune system," he says.However, earlier this year, many analysts expected Tysabri would take over the MS market, effectively sidelining competition from Teva (nasdaq: TEVA - news - people ) and Serono (nyse: SRA - news - people ). That, Hittle says, is unlikely to happen. The PML issue could make it, "a real medicine of last resort."
Biogen and Elan say that they are taking preliminary steps to restart clinical trials of Tysabri in MS, which could help further define the drug's benefits and risks. Executives on a conference call were optimistic that Tysabri might return to the market for some patients. "We're encouraged that it will be coming back to the market," said James Mullen, chief executive of Biogen Idec.
Despite Mullen's optimism, there is still room for doubt on Tysabri. On a conference call with analysts at Sanford C. Bernstein last week, Daniel Wynn, a multiple sclerosis investigator, said that most patients being evaluated for safety were not given spinal taps--the most conclusive test for PML and the virus that causes it. Based on today's conference call with the companies, Wynn appears to have been correct.
"I think they are being very cautious on their language," says Geoffrey Porges, the biotech analyst at Bernstein. "The companies have said that there are 'no new confirmed cases', not 'no new potential cases.'"
Porges says he would still like to know how many patients who did not have spinal taps had suspected cases of PML. "I think we are still several steps away from a final decision," Porges says, "but this is now set up for a showdown with the regulatory agencies with patients and the companies on one side and safety oversight and caution on the other side."
http://www.forbes.com/home_europe/technology/2005/08/09/drugs-biogen-tysabri-cx_mh_0809tysabri2.html
posted by Bill at 6:28 AM
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