Lisa LaMotta. Biogen’s Tecfidera Dogged By PML. SCRIP Mon, 21 Sep 2015
A third case of a deadly brain disease has been confirmed for Biogen’s blockbuster oral multiple sclerosis Tecfidera – analysts say it’s manageable – but sales are likely to slump.
Analysts confirmed that a third case of progressive multifocal leukoencephalopathy (PML), a deadly brain disease, has occurred in a patient taking only Tecfidera (dimethyl fumarate). Like the two previous cases, the disease occurred in patients with prolonged white blood cell suppression – a condition known as lymphocytopenia. It is believed that only patients with severe lymphocytopenia could develop PML. The drug’s label was revised to reflect the PML death. PML has been known to crop up in patients taking certain MS drugs long-term – Biogen’s Tysabri (natalizumab) has had a long-running problem with the issue – but drugmakers have learned to screen patients better for certain signs that could indicate whether they will develop the fatal brain condition. Tysabri, for example, has a companion diagnostic that tests patients for the presence of JVC antibodies – those that are negative are less likely to develop PML. The creation of the test has led to fewer cases of PML for Tysabri patients and has bolstered sales of the drug The oral multiple sclerosis drug had one of the best drug launches in history when it entered the market in 2013, but increasing competition to the oral MS market, as well as other advances in the field and safety concerns have slowed revenues.
The first case of PML in a Tecfidera patient popped up in October 2014 and sales of the drug have been on a downward slide ever since. Biogen insists that Tecfidera is safe and has said for the last year that the cases of PML are not affecting sales of the drug. The company says that sales of the drug have been waning due to cannibalization by Biogen’s other MS drugs, as well as the increased competition in the market.
Jefferies analyst Brian Abrahams wrote in a Sept. 18 note that he believes the risk of the disease can be easily mitigated by physicians if they closely monitor patients’ white blood cell counts.