Efalizumab is Raptiva.
Harry is correct in that it is one of a number of monoclonal antibodies developed in the past few years (some in development for 20 years +- before reaching market) to treat autoimmune diseases.

As I see it, the problems arising from monoclonal antibodies is that they are used as last resort medications for the most part, when nothing else available has worked to slow whatever autoimmune disease they are being used to treat. That usually means forms of chemotherapy and other VERY strong immune suppressing drugs. As we are seeing now with Tysabri, it's use after the patient being on methotrexate, azathioprine, mitoxantrone, etc, seems to be a trend and creates a stronger chance of PML because the immune system is still not reconstituted from the use of those other agents.

Unfortunately, the news about PML and Tysabri has been trumpeted and kept in the news since it's return to market. What we don't hear about is the PML associated with these other MABs. They have them. It's just not trumpeted the way it is with Tysabri.

Look it up for yourself. http://www.fda.gov/cder/aers/default.htm

Does that make them bad medicines if a known side effect is possibility of PML? Should they be withdrawn from market because they MIGHT cause a patient to be more susceptible to PML? Should the patient not have their choice? Should one drug be singled out because of PML when it's a known side effect of MABs? Maybe they need to be tried first instead of after other drugs?