Four deaths linked to MS drug Tysabri, say authorities
Tysabri: linked to deadly brain infecction PML
Friday October 30 2009
Elan and Biogen Idec's multiple sclerosis drug Tysabri has been linked to four deaths by the European Medicines Agency.
The European drug regulators confirmed the four deaths, tied to a deadly brain infection progressive multifocal leukoencephalopathy or PML, in a statement yesterday.
Shares in the two firms fell on the news yesterday. Elan hit a new year low before finishing flat at €3.44 yesterday.
The news comes just a week after the agency said it would be reviewing Tysabri, citing 23 cases of PML.
That number is far higher than the previously known figure of 13 cases. Elan shares fell nearly 20pc as a result of the news last Friday. Biogen dropped over 7pc.
A spokeswoman for the US Food and Drug Administration also said there have been 24 confirmed cases since 2006 but said the agency was "still receiving and reviewing follow-up information information on cases of PML".
Tysabri was removed from the market for 18 months, beginning in 2005, because of the link to PML.
The drug was allowed back on the market after patients and physicians pushed for its return. It is a key revenue driver for both firms and produces nearly $1bn in annual sales.
European regulators also reported another case of potentially deadly brain infection in patients on Tysabri since Friday, taking the worldwide total since 2006 to 24.
Of those, 16 cases have occurred in Europe, compared to eight in the US.
Confused
The imbalance of PML cases in Europe has confused analysts and, despite its investigations, Biogen has been unable to explain the difference.
Some Wall Street analysts have questioned whether some US cases have slipped through the cracks, but Biogen has vehemently denied this, saying the risk-management programme for Tysabri in America is rigorous.
The number of PML cases among Tysabri users is closely watched, as its label suggests an infection risk to one in every 1,000 patients.
Despite the PML risk, Tysabri is still seen as one of the most effective MS treatments on the market. Leerink Swann analyst Joshua Schimmer said in a note:
"For a disease which previously had an extremely high mortality rate, an 83pc rate of survival is outstanding."
- Ailish O'Hora
Irish Independent
