Biogen, Elan Win FDA Approval of Label Change for Tysabri

Biogen Idec Inc. and Elan Corp. won U.S. 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 will help doctors identify patients with the highest and lowest risks of developing deadly brain infections linked to the drug, the agency said today in a statement.

The label change may push Tysabri’s global sales to $2.5 billion to $3 billion by 2016, Michael Yee, an analyst at RBC Capital Markets in San Francisco, said yesterday in an interview yesterday. Without the modification, sales may have reached $1.5 billion to $2 billion that year, Yee said. Biogen and Dublin-based Elan split the drug’s revenue.

“Tysabri has benefited thousands of patients worldwide who are living with multiple sclerosis,” George Scangos, chief executive officer of Weston, Massachusetts-based Biogen, said in a statement. “Research and scientific expertise has allowed us to gain a better understanding of the benefit-risk profile for Tysabri.”

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 boxed warning the drug’s label has carried since 2006.

New Label

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 the antibodies. Biogen developed a blood test known as a JCV assay to determine whether a person has the antibodies.

“The revision of the Tysabri label to include the use of the JCV assay as a risk-stratification tool is important for doctors and patients because it allows Tysabri to be most efficiently used in the safest group of patients,” Yee said.

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. The test, also approved today by the FDA, will be offered exclusively in the U.S. by Quest Diagnostics Inc., the Madison, New Jersey-based company said in a statement.

About 400,000 people in the U.S. and 2.1 million worldwide have MS, according to the New York-based National Multiple Sclerosis Society. Common symptoms include numbness, loss of vision and mobility, and cognitive dysfunction.

Risk Factors

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, 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.

As of February 2011, 102 cases of PML had been reported among 82,732 patients treated with Tysabri worldwide, the FDA said April 22 in its most recent safety update on the drug.

Tysabri won FDA approval in 2004 for multiple sclerosis, a neurological disorder that causes a person’s immune system to attack healthy nerve cells.

The risk of PML emerged after Biogen and Elan began marketing Tysabri, leading to the suspension of sales in February 2005. The drug returned to the market in June 2006 with a risk management program for patients who didn’t benefit from rival medicines after research showed it was twice as effective as other MS treatments.

Teva Pharmaceutical Industries Ltd.’s Copaxone, Merck KGaA’s Rebif and Bayer AG’s Betaseron are among injectible MS treatments that compete with Tysabri. Novartis AG’s Gilenya, approved by the FDA in 2010, is the first pill to treat the condition. MS drugs generally must be taken throughout a patient’s life to reduce flare-ups and delay disability.

The worldwide market for MS drugs, now $10 billion to $11 billion, may grow to $15 billion in 2016, Yee said. Tysabri’s share of the market, now about 10 percent to 13 percent, may grow to 20 percent that year with the revised label, he said.

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