Analyst report concludes Tysabri/Avonex combo might have lead to deathsBiogen Idec and Elan's multiple sclerosis drug Tysabri may have killed patients because of an adverse interaction with the Biogen multiple sclerosis drug Avonex, according to an investors from Ireland's NCB Stockbrokers.
The investors' note, written by NCB analyst Orla Hartford, said an interaction of Tysabri and Avonex "essentially leads to almost double the intended Tysabri concentration after only 20 weeks. . . Patients on Tysabri alone did not accumulate the drug."
Hartford based her findings on analyzed data submitted to the FDA during the approval process.
A spokeswoman for Elan told Bloomberg News the company is "continuing with the review (of Tysabri) and will comment when it has been completed."
Biogen Idec and Elan told MM&M earlier this year that they expect to issue a decision on Tysabri in the second half of 2005.
Tysabri was removed from the market in March after being linked to progressive multifocal leukoencephalopathy, a rare neurological disease most often found in patients with compromised immune systems. Hartford said in the Bloomberg News report that the Tysabri accumulation may have led to a suppressed local immune system partially because the body is less able to process it, which leads to an overdosing.