In June 2009, Genentech, Inc. ­withdrew the psoriasis drug Raptiva from the ­market after it was linked to deaths of at least three patients from a rare but often fatal brain ­disease, progressive multifocal leukoencephalopathy (PML). Although 80% of people are said to harbor the virus that causes PML, the disease occurs almost exclusively in people with severely ­weakened immune systems. ­Raptiva is an immunosuppressant, as are many conventional drugs aimed at treating psoriaisis.

One more reason to try homeopathy first!