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Author: Vanessa Ngan, Staff Writer, 2003.

Table of contents

Efalizumab (Raptiva™) is no longer available. It was withdrawn from the market in 2009. This information page is of historical interest only.

Efalizumab belongs to the class of biological response modifiers called T-cell blockers. It is an effective treatment in patients with moderate to severe plaque psoriasis.

How does it work?

Efalizumab is a genetically modified form of mouse protein that is directed at blocking T cell activation and proliferation by binding to CD11a receptors on T cells. This stops the T cells from releasing cytokines, which are the primary cause of the inflammation, redness, itching and flaky skin patches characteristic of psoriasis.

How is it given?

Initial trials of efalizumab involved intravenous (IV) administration of the drug. However, a subcutaneous (SC) formulation has been developed and is currently being used. Once weekly dosing for a 12-week period improves psoriasis to some degree in about 50% of patients.

Improvements in psoriasis made after 12 weeks of treatment can be maintained with further weekly doses or every-other week dosing.

Side effects

Efalizumab appears to be well tolerated. The most frequently reported side effects included headache, nausea, chills, pain, fever and non-specific infection such as the common cold. These occurred most often after the first injection and became less with subsequent doses.

Risks of treatment

Efalizumab is an immune supressing agent and so increases susceptibility to infections.

WARNING: 9 April 2009. Genetech decided to voluntarily withdraw efalizumab (Raptiva) from the US market due to a potentially increased risk of progressive multifocal leukoencephalopathy (PML).
19 February 2009. The US Food and Drug Administration (FDA) Center for Drug Evaluation and Research has issued a Public Health Advisory Updated Safety Information about Raptiva (efalizumamb) because of four reports of patients taking this drug that developed the rare life-threatening brain infection, Progressive Multifocal Leukoencephalopathy (PML) and other infections.

New Zealand approved datasheets are the official source of information for these prescription medicines, including approved uses and risk information. Check the individual New Zealand datasheet on the Medsafe website.



  • Leonardi GL. J Am Acad Dermatol 2003;49:S98-104.
  • Public Health Advisory Updated Safety Information about Raptiva (efalizumamb) – US Food and Drug Administration (FDA) Center for Drug Evaluation and Research 8 April 2009.

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