Efalizumab

In February 2009, due to serious side effects, a selective (!) humanized IgG1 antibody with binding sites for the CD 11α chain of LFA-1 (Leucocyte Function Associated Antigen 1; see integrins below) on the surface of T cells was withdrawn from the market. This prevents T cells from binding to ICAM1 and other ICAMs (see adhesion molecules below) on endothelial surfaces. The T cells can no longer migrate from the vessels into the tissue, dermis and epidermis. The release of pro-inflammatory cytokines is also prevented.

In several patients, long-term therapy (> 3 years) with efalizumab resulted in progressive multifocal leukoencephalopathy (PML = rare progressive demyelinating disease caused by activation of the polyomavirus JC, which is present in latent form in 80% of healthy adults). The product has been withdrawn from the market because of this side effect!

Other side effects include Guillain-Barreé syndrome, Miller-Fisher syndrome, encephalitis, meningitis and opportunistic infections.

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