title: Assessing long-term drug safety: lessons (re) learned from raptiva.
abstract: Efalizumab was approved for moderate to severe psoriasis in 2003 based on studies in approximately 2700 patients, of whom only 218 were exposed to the drug for more than 1 year. In 2009, after more than 46,000 patients were exposed to efalizumab, the drug was withdrawn from the market after 3 confirmed and 1 suspected case of progressive multifocal leukoencephalopathy (PML) were spontaneously reported. As PML is very rare, it is extremely unlikely that the 4 reported cases were due to chance and given that PML occurs primarily in patients who are immunosuppressed, the association is likely causal. The identification of PML as a serious, but statistically rare risk of efalizumab demonstrates the strengths and weaknesses of the current drug approval and pharmacovigilance processes for fully measuring the safety of a drug. Patients and clinicians need to be aware of the relative completeness and limitations of existing safety data of a drug when selecting a treatment.
authors.affiliation: Department of Dermatology, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Nicole M
authors.initials: NM
authors.lastname: Seminara
authors.forename: Joel M
authors.initials: JM
authors.lastname: Gelfand
mesh_terms: D000911:Antibodies, Monoclonal / Q000009:adverse effects*; D061067:Antibodies, Monoclonal, Humanized; D017277:Drug Approval / Q000458:organization & administration*; D064420:Drug-Related Side Effects and Adverse Reactions / Q000453:epidemiology*; D006801:Humans; D011358:Product Surveillance, Postmarketing; D011565:Psoriasis / Q000188:drug therapy*
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; C472181:efalizumab