Biogen Idec and Elan Corp have launched the first oncology clinical trial of their multiple sclerosis drug Tysabri.

The two firms said that the first dose of Tysabri (natalizumab) was administered yesterday in a Phase I/II study to evaluate the drug in patients with relapsed or refractory multiple myeloma. In the Phase I portion of the trial, a standard dose-escalation design will be used to assess the safety and tolerability of Tysabri in up to 12 patients and in the Phase II part, up to 30 patients will be randomised to the tolerated doses identified in the first part of the study.

Biogen and Elan added that treatment cycles will consist of intravenous infusions of Tysabri once every 28 days for six months. Patients eligible for the study must have relapsed or refractory multiple myeloma and have failed or cannot tolerate therapy with bortezomib and thalidomide or lenalidomide.

Wayne Saville, director of oncology at Biogen Idec, said that because Tysabri is a monoclonal antibody that targets VLA4, or alpha-4 integrin, it has real potential in this indication as VLA4 is also found on the surface of MM cells and may be involved in their survival. The therapy may be effective in a number of other cancers and is “a meaningful addition to Biogen Idec’s robust oncology pipeline”.

The news comes as a boost to the two firms as Tysabri has been put under the spotlight again of late after new cases of the rare brain disease progressive multifocal leukoencephalopathy were reported in patients with MS taking the drug as monotherapy. These were the first cases of PML to be reported following Tysabri’s re-appearance on the market in June 2006 and while regulators in the USA and Europe are considering label changes, they have stated that there is no intention of pulling the drug from the market again.

As well as MS, Tysabri is also approved in the USA for the treatment for moderate-to-severe Crohn's disease in patients who have failed or cannot tolerate available therapies.