The withdrawal of Tysabri after the drug was linked to a fatal brain disease, which was shortly followed by the resignation of Biogen Idec’s general counsel, has prompted the FDA to place a clinical hold on studies with the a4 integrin antagonists class.
The hold, which spells out further bad news for an MS community still reeling from the Tsyabri blow, includes studies with GlaxoSmithKline and Tanabe Seiyaku’s phase II MS and Crohn’s disease compound SB-683699/T-0047.
GSK and Tanabe have been forced to halt the trial due to the uncertainty surrounding the cause of two reports of progressive multifocal leukoencephalopathy (PML) in patients taking Tysabri plus Avonex. Although GSK and Tanabe’s compound is chemically unrelated to Tsyabri, the two drugs do have the same molecular target.
Shortly after this revelation, another blow was dealt by Biogen Idec when it issued an important drug warning stating that Avonex could cause severe liver damage, including liver failure, in rare cases.
In a letter to the FDA, Biogen revealed that it has updated the product’s warning label to reflect these newly-announced safety risks and advised doctors to monitor patients taking the medication for signs of liver damage.
This second recent blow to the company is particularly acerbic as investors’ looked to Avonex following the suspension of Tysabri, which itself was pitted to become a blockbuster drug. Furthermore if patient confidence drifts to rival and alternative products as a result of these safety concerns, as was the case with the COX-2s, Biogen stands to lose out to products such as Serono’s already fast-growing Rebif.