It's a powerful immunosuppressant known as a monoclonal antibody, and it's been licensed as a therapy for non-Hodgkins lymphoma.
Despite the supposed limitations of its use, doctors have also been giving it to patients with the auto-immune disease, systemic lupus erythematosus (SLE), or lupus.
Around 10,000 SLE patients have been given Rituxan in the USA alone - and it was two of these who died in 2006. They both had a viral infection of the brain, known as PML (progressive multifocal leukoencephalopathy).
The future of the drug is uncertain, but while drug regulators deliberate, doctors are being told to watch out for early signs of PML in patients being given Rituxan.
(Source: FDA website).
E-news broadcast 4 January 2007 No.322 [Subscribe]