The Forest Whispers My Name III » death

7 more PML infections, 1 more death in Tysabri MS patients

pmb — Sat, 19 Mar 2011 08:50:03 +0000

Biogen Idec Inc. reported 7 more cases of a rare brain infection among multiple sclerosis patients taking Tysabri, sold with Elan Corp. bringing the total number of affected patients to 102 as of March 4.

The Weston, Mass., biotech company reported that one more of those patients has died, bringing the total to 21. The cases of the infection–known as progressive multifocal leukoencephalopathy, or PML–are closely watched as the MS market becomes increasingly competitive.

The drug is generally regarded as highly effective, but mostly used for patients that have stopped responding to other drugs or have aggressive cases of the disease.

Biogen recently halted enrollment in a major clinical trial aimed at testing the earlier use of Tysabri, citing a slower-than-expected pace of finding participants and the desire to devote resources toward “risk stratification” efforts for the drug.

Biogen is developing a blood test that may better determine the chances of patients contracting PML. The test recently received CE Mark approval in Europe and the companies are conducting large studies of its effectiveness.

Regulators have said that they monitor cases of PML as they occur and have concluded that the benefits of the medicine outweigh the risks. Tysabri was withdrawn from the market in 2005 and relaunched in 2006–because of its effectiveness–with a strict access plan that monitors patients.

The overall global PML rate is now at 1.23 per 1,000 patients. A Biogen spokeswoman said the current PML figure is “still generally within what we saw in clinical trials.”

Of the total PML cases, 55 were in the U.S., 42 were in the European Union and five in other areas.

The risk of the infection generally increases with the number of monthly infusions that a patient receives, but that rate appears to drop after 30 months. Biogen is studying this drop and warns there are limited data from patients on the drug longer than 36 months.

The most recent data translate to a rate of 1.87 cases per 1,000 patients on the drug for a year or longer, rising to 2.41 per 1,000 for those on the drug for two years or longer, and dropping to 1.4 for more than three years.

Looked at another way, the rate is about 1.68 cases per 1,000 patients on the drug for between two and three years. The incidence is about 0.44 case per 1,000 patients in those using it for one to two years, and it is essentially nonexistent in patients using it for less than a year.

Biogen shares drop on 10th Tysabri PML case

pmb — Wed, 01 Jul 2009 19:02:14 +0000

Shares of Biogen Idec sank after the biotechnology giant confirmed that another patient taking the multiple sclerosis drug Tysabri has been diagnosed with a potentially fatal brain infection called progressive multifocal leukoencephalopathy, or PML.

The patient, who lives overseas and had been taking Tysabri for more than 30 months, is the 10th person to come down with PML since the multiple sclerosis drug was allowed back onto pharmacy shelves in 2006. Three of those cases have been diagnosed this month.

The news prompted Deutsche Bank to lower its rating on Biogen Idec’s stock to “hold” from “buy.” Investors responded with a sell-off that pushed shares of Biogen (Nasdaq: BIIB) down 5.5 percent, to $47.32, at the close of trading Monday.

Tysabri, which Biogen Idec produces at its manufacturing facility in Research Triangle Park, is seen as a critically important product for the company and its partner on the drug, Irish pharma Elan (NYSE: ELN).

Tysabri was intended to be an improved treatment for MS that could take the place of blockbuster MS treatment Avonex, Biogen’s top-selling drug and one also made in RTP.

But Tysabri has had trouble with PML since first coming on the market in 2004. The drug was shelved by the Food and Drug Administration in 2005 because three patients who had taken Tysabri in clinical trials developed PML, with two of the cases fatal.

The FDA allowed Tysabri back on the market a year later under a special risk monitoring program.

Tysabri has worked well to combat multiple sclerosis symptoms in patients but it has not generated the revenue the Biogen and Elan had projected – due in most part to PML worries. The three PML cases reported this month have come in patients who had taken Tysabri for 30 months or longer, and fears are growing that prolonged exposure to Tysabri increases the risk of PML. Biogen Idec disputes that conclusion.

Still, some doctors have started giving patients a holiday from Tysabri in an effort to avoid PML. In such scenarios, a patient takes Tysabri for two years before taking a break from the drug and turning to other therapies for treatment. That trend is putting further downward pressure on the drug’s sales.

Cambridge, Mass.-based Biogen Idec, which employs almost 1,000 people in RTP, said in February that it would struggle to meet its goal of 100,000 Tysabri patients by 2011. The news of yet another PML case likely puts that target even further out of reach.

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