Tysabri trials show impressive results – but there is a small risk
03 Mar 2006
Two trials of Tysabri (natalizumab) have shown significant reduction in the rate of disease progression in patients with relapsing remitting multiple sclerosis. A review of more than 3000 patients treated with the drug in trials has also shown that the drug is associated with a small risk of the rare neurological disease progressive multifocal leukoencephalopathy (PML). The findings are reported in the New England Journal of Medicine.
Tysabri was approved by the US Food and Drug Administration in November 2004 for the treatment of MS, but its use was voluntarily suspended by Biogen Idec and Elan Pharmaceuticals in February 2005 after cases of PML were reported. The FDA's Advisory Committee will review the drug at its meeting on 7 and 8 April.
Mike O’Donovan, chief executive of the MS Society, said, “The trial results are impressive and we very much hope Tysabri will become available in the UK, with careful monitoring to minimise the small risk which has been identified.”
In one of the trials, a team led by Dr. Chris Polman of the VU Medical Centre in Amsterdam recruited 942 patients who were randomly assigned to receive natalizumab or a placebo every four weeks.
After two years of treatment, Tysabri showed a 42% reduction in the risk of a sustained increase in disability and 68% reduction in the risk of relapse, compared with placebo. The drug also reduced the number of new or enlarging MS lesions seen on MRI scans by 83%.
In the second trial, Dr. Richard Rudick of the Cleveland Clinic Foundation in Ohio and his colleagues looked at 1171 people with MS who had had at least one relapse during a 12-month period while being treated with beta interferon. They were randomly given Tysabri or placebo every four weeks while continuing on the other drug.
Over two years, those receiving tysabri showed a 24% reduction in the risk of sustained increase in disability, a 55% reduction in rate of relapse, and an 83% reduction in new or enlarging lesions, compared with beta interferon alone.
Dr Rudick told Reuters that the two trials showed "the effectiveness of tysabri was “very excellent” and far better than that of the other available disease-modifying drugs.
After three cases of PML were reported, Dr. Eugene Major of the National Institute of Neurological Disorders and Stroke in Bethesda, Maryland, led an independent committee to evaluate suspected cases of the disease in 3417 patients exposed to tysabri in trials. PML was ruled out in 43 out of 44 patients with possible PML and the other case was found to be indeterminate.
Dr Rudick said he hoped the FDA would again approve tysabri for patients "who really need it", with close monitoring so that any early symptoms of PML could be recognised and treatment stopped. "The decision to use it should be made by the doctor and the patient together,” he said.
Before the drug could become a licensed treatment in the UK, it would need approval from the European Agency for the Evaluation of Medicinal Products. Once licensed, it would also be likely to be referred to NICE.
Mike O’Donovan, chief executive of the MS Society, said, “The trial results are impressive and we very much hope Tysabri will become available in the UK, with careful monitoring to minimise the small risk which has been identified.”
In one of the trials, a team led by Dr. Chris Polman of the VU Medical Centre in Amsterdam recruited 942 patients who were randomly assigned to receive natalizumab or a placebo every four weeks.
After two years of treatment, Tysabri showed a 42% reduction in the risk of a sustained increase in disability and 68% reduction in the risk of relapse, compared with placebo. The drug also reduced the number of new or enlarging MS lesions seen on MRI scans by 83%.
In the second trial, Dr. Richard Rudick of the Cleveland Clinic Foundation in Ohio and his colleagues looked at 1171 people with MS who had had at least one relapse during a 12-month period while being treated with beta interferon. They were randomly given Tysabri or placebo every four weeks while continuing on the other drug.
Over two years, those receiving tysabri showed a 24% reduction in the risk of sustained increase in disability, a 55% reduction in rate of relapse, and an 83% reduction in new or enlarging lesions, compared with beta interferon alone.
Dr Rudick told Reuters that the two trials showed "the effectiveness of tysabri was “very excellent” and far better than that of the other available disease-modifying drugs.
After three cases of PML were reported, Dr. Eugene Major of the National Institute of Neurological Disorders and Stroke in Bethesda, Maryland, led an independent committee to evaluate suspected cases of the disease in 3417 patients exposed to tysabri in trials. PML was ruled out in 43 out of 44 patients with possible PML and the other case was found to be indeterminate.
Dr Rudick said he hoped the FDA would again approve tysabri for patients "who really need it", with close monitoring so that any early symptoms of PML could be recognised and treatment stopped. "The decision to use it should be made by the doctor and the patient together,” he said.
Before the drug could become a licensed treatment in the UK, it would need approval from the European Agency for the Evaluation of Medicinal Products. Once licensed, it would also be likely to be referred to NICE.
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