IRISH biotech group Elan and its US partner Biogen Idec last night won US clearance to modify the label of their multiple-sclerosis shot Tysabri with new safety information that may double the treatment’s worldwide sales.
The Food and Drug Administration approved the revision that would help doctors identify patients with the highest and lowest risks of developing deadly brain infections linked to the drug, the agency said in a statement.
The news comes as one of the drug’s main rivals, Novartis’s Gilenya, became the subject of a safety review by the European Medicines Agency.
The agency advised doctors yesterday to continuously monitor patients for six hours after giving them a first dose of Gilenya, casting a shadow over the potential blockbuster product, following reports of heart problems in patients and the death of one person in the United States within 24 hours of starting treatment.
The Swiss drug maker said last month it was investigating whether Gilenya, seen by analysts as a potential multibillion-dollar seller, caused the death of the 59-year-old US patient.
Tysabri’s label change may push global sales to between €1.9 billion and €2.3 billion by 2016, Michael Yee, analyst at RBC Capital Markets, said yesterday. Without the modification, sales may have reached €1.15 billion to €1.5 billion that year, he said.
Tysabri increases the risk of progressive multifocal leukoencephalopathy, or PML, a viral infection in the brain that usually leads to death or severe disability, according to a warning the drug’s label has carried since 2006.
The new label will retain the boxed warning, the FDA’s strictest caution, while adding a notification that patients who have antibodies against the JC virus are more likely to develop PML while taking Tysabri than people who don’t have them. Biogen and Elan developed a blood test known as a JCV assay to determine whether a person has the antibodies.
The European Commission approved the label change in June, and the JCV test has been widely used by doctors in Europe since then, he said. About 400,000 people in the US and 2.1 million worldwide have MS, according to the New York-based National Multiple Sclerosis Society.
Data collected by the companies shows a patient who tests negative for the antibodies may have 1 chance in 10,000 of developing PML while taking the drug, Mr Yee said. Without the use of the JCV test, patients are estimated to have a 1.5 in 1,000 risk of developing the brain illness after two years of treatment, according to the drug’s label.
The global market for MS drugs, now between €7.7 billion and €8.5 billion, may grow to €11.5 billion in 2016, Mr Yee said. Tysabri’s 10 per cent share of the market may grow to 20 per cent that year with the revised label, he said.
