Early detection of PML in multiple sclerosis patients treated with immune-suppressing drugs may improve survival

SAN DIEGO — Early detection of a deadly brain infection that sometimes arises due to treatment of autoimmune disorders with immune-suppressing biotech drugs may improve survival, according to a new study.

The study, released Sunday and scheduled for presentation at the 65th annual meeting of the American Academy of Neurology in San Diego, which starts next Saturday, found that early detection of progressive multifocal leukoencephalopathy, or PML, may improve survival and disability levels.

The study examined 319 people with multiple sclerosis who had received treatment with Tysabri (natalizumab) and were diagnosed with PML; Elan Pharmaceuticals and Biogen Idec, the companies that developed and market the drug, supported the study. The study compared people who had symptoms of PML when they were diagnosed with people who did not have symptoms but were diagnosed via brain scans and spinal fluid tests. The level of disability was assessed before the PML diagnosis, at diagnoses and again six months and then one year after diagnosis. PML results from the JC virus, a virus that lies dormant in most adults, but can be activated when the immune system is suppressed due to treatment with immune-suppressing drugs or in later stages of AIDS.

A total of 21 people had no symptoms at diagnosis, while 298 people did, and preliminary data from the study suggest that people without symptoms may have improved survival and less disability than those who had developed symptoms before diagnosis.

As of Jan. 1, 2013, all of those 21 people were living, compared with 77 people with PML symptoms who had died, according to the study.