Drug 'holidays' may make Tysabri safer

Hot on the heels of the announcement that another Tysabri patient had developed PML comes another bit of related news--one that could contain a ray of hope for managing the risk of brain infection among MS and Crohn's patients who use the Biogen Idec/Elan drug.

Researchers at UT Southwestern Medical Center found that Tysabri, a.k.a. natalizumab, may make some patients vulnerable to infection by reducing the number of immune cells in the brain. "Natalizumab is very effective in keeping pro-inflammatory cells out of the brain to reduce damage from MS," the study's lead author, Dr. Olaf Stüve, said in a statement. The problem with that, he said, is that it interferes with immune surveillance against infections of the brain and spinal cord, so they may go undetected by the body until they grow serious.

But, the authors suggest, Tysabri could be made safer and more effective if patients would take treatment "holidays," rather than using the drug continuously over long periods of time. The only problem with that, Stüve said, is that the new study "has limitations because of the small number of autopsies ... involved." The treatment holiday idea should be tested in clinical trials, he said.

- read the UT Southwestern release
- see the Hays article