Elan co-markets the drug with Biogen. Biogen issued higher than expected quarterly figures for Tysabri® in July, indicating the number of new users increased at the highest rate in over a year.
“We are making progress across all aspects of our company,” said Chief Executive Kelly Martin.
“Tysabri® continues to grow in double-digits,” he said. “Demand for the product is strong both in the U.S. and outside the U.S.”
The company makes an added $100 million every time 10,000 more patients buy Tysabri®. It is expected that the medication will increase the overall growth in the company’s bottom line by 15 percent annually for the next three to five years.
Tysabri® (the generic is natalizumab) is a monoclonal antibody. It was approved in November 2004, but pulled from the market several months later when a few patients taking the medication to treat multiple sclerosis contracted a fatal brain infection, progressive multifocal leukoencephalopathy (PML).
PML is a lethal viral disease of the brain. The virus, known as the JC virus, remains latent in the human body until it overcomes a weakened immune system. Once in the brain, it begins to destroy the myelin covering of the nerve cells. Progressing in an inexorable downward spiral, PML kills most victims within an average of six months.
Tysabri® was released back onto the market in June 2006 with onerous restrictions on who could use the drug. Patients had to be enrolled in and were monitored by a strict “risk mitigation strategy” to keep track of any possible symptoms of PML in Tysabri® patients. The strategy helped physicians know more about and manage the risks of PML in their patients.