Elan Corporation and partner Biogen Idec saw a much-welcome rise their respective share prices yesterday after the New England Journal of Medicine said that it might be possible to make an earlier detection of the often fatal virus that led to the withdrawal of their multiple sclerosis drug, Tysabri (natalizumab), which would allow patients to recover.

Analyses are currently underway to assess the risk of developing the rare condition, known as progressive multifocal leukoencephalopathy, or PML, in patents treated with Tysabri. An independent panel with expertise in the diagnosis and management of PML is reviewing all suspicious and ambiguous findings to evaluate them for possible PML, which is hoped to lead to a better understanding of the risks.

One report has so far have suggested that PML may be preceded by a specific virus, while another has demonstrated that PML is not uniformly fatal. “It is possible that testing for the appearance of [the] virus in plasma, along with a high degree of clinical suspicion, will permit early diagnosis and discontinuation of [Tysabri] therapy and allow patients to recover,” the NEJM commented in an editorial forming part of a series of articles published in its online edition about Tysabri.

The Tysabri withdrawal earlier this year was a huge blow to both Elan and Biogen Idec, which had counted on huge revenues from the highly-touted drug [[01/03/05a]]. However, both firms and investors alike seem to be confident that the drug might be able to find its way back to market [[27/05/05c]].