GSK said late yesterday the FDA halted Phase II clinical trials of its candidate drug 683-699, which it had been testing to treat MS.
The drug is similar in action to Tysabri, which was pulled from the market by developers Biogen Idec (NASDAQ: BIIB - news) and Elan Corp (Dublin: ELN.I - news) , after it was linked to a brain disease called progressive multifocal leukoencephalopathy (PML).
According to Glaxo, while 683-699 is designed to interact with the same biological molecules as Tysabri, it is a very different compound. Glaxo's 683-699 is a traditional chemical medication taken in pill form, while Tysabri is a biological compound, based on an antibody, that is injected.
Biogen (NASDAQ: BGEN - news) and Elan pulled Tysabri on Feb 28 after two patients in a Phase III clinical trial tested positive for PML. The FDA had approved Tysabri in late November, on only one year's worth of Phase III clinical data under its accelerated approval program.
GlaxoSmithKline spokesman Rick Koenig said all MS drugs that target the same molecules in the body as Tysabri are being scrutinized to see whether there is a connection between this particular biological mechanism and the onset of PML.
'It's a cautionary measure until the FDA can get a full understanding of what happened,' Koenig added.
When asked Tuesday what he made of the FDA's decision on Glaxo's 683-699, Elan Chief Executive Kelly Martin said he was not surprised.
'It's very logical. We assumed it would happen,' Kelly added.
Glaxo ADRs closed down 0.7 percent at $48.35 yesterday.
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