Tysabri testing underway

Biogen Idec aims to use drug for cancer

Biogen Idec Inc. still hopes to find new uses for its multiple sclerosis drug Tysabri, even though some patients have contracted a potentially fatal brain disease.

The Cambridge biotech company and its Irish partner, Elan Corp., said yesterday they have launched a clinical trial to test whether Tysabri can be used to treat relapsed or refractory multiple myeloma, a type of cancer of plasma cells. And in the long run, the companies suggested, they could use Tysabri as a treatment for other forms of cancer.

"We've always said that we want to explore Tysabri in other indications where we thought the mechanism of action would show promise," said Naomi Aoki, a spokeswoman for Biogen Idec.

The Food and Drug Administration gave the companies permission in January to market the MS drug for Crohn's disease, a chronic gastrointestinal disorder, but it will likely take years to prove the drug is an effective weapon against cancer. Still, the announcement is significant because it comes just two months after Biogen Idec reported two more Tysabri patients contracted a rare and serious brain disease called progressive multifocal leukoencephalopathy, or PML, the first cases since 2005.

Biogen Idec and Elan launched Tysabri in 2004, but pulled it from the market in just a few months after some patients were diagnosed with PML; two of them later died. The companies reintroduced Tysabri two years ago with stricter prescription guidelines and prominent warnings about the PML potential. The drug's label warns that 1 in 1,000 patients could potentially contract the brain disease, but many doctors argue the drug is worth the risk for patients facing serious diseases like MS who are without other viable options. Many MS patients have said the drug is the most effective treatment they have used.

Also, some doctors are hopeful they might be able to treat PML if caught early enough. While one of the two new PML patients remained hospitalized as of Aug. 26, the company said the patient was stable and showed "improved cognition." The other patient was also doing well, according to Biogen Idec. More than 31,800 patients were using Tysabri as of June.

Separately, however, the Food and Drug Administration said yesterday it is investigating another potential safety risk associated with the drug - melanoma, a potentially deadly form of skin cancer. Tysabri was one of 20 drugs that appeared on the FDA's list of products with potential safety risks identified from its database of adverse events during the first quarter of this year. In February, the New England Journal of Medicine reported two MS patients developed malignant melanomas shortly after starting treatment with Tysabri. But Biogen Idec said it found no increased risk of melanoma in clinical trials.

If Biogen Idec eventually wins approval to use Tysabri to treat multiple myeloma, it could potentially compete with Velcade, a cancer drug marketed by Millennium Pharmaceuticals Inc. of Cambridge. Takeda Pharmaceutical of Japan purchased Millennium for $8.8 billion this year largely based on Velcade's surging sales.

But Dr. Nancy Simonian, Millennium's chief medical officer, said doctors often prescribe multiple drugs for cancer patients, raising the possibility that Velcade could be used in combination with Tysabri to treat myeloma. To reduce the risk of PML in MS patients, however, Tysabri's label currently recommends it be used alone.

Alternatively, because of Tysabri's potential side effects, doctors may decide only to use the drug after Velcade and other treatments have failed.

"Our feeling is that [Biogen Idec's] trial is really good news," said Simonian. "It provides multiple myeloma patients with a potential new treatment option."

Todd Wallack can be reached at twallack@globe.com.