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Tysabri Proven Ineffective in Treating SPMS Patients

April 26, 2016

Researchers showed evidence that Natalizumab (Tysabri) was ineffective in slowing disease progression in SPMS patients.

The ASCEND trial missed its primary endpoint of reducing progression as measured by a composite endpoint assessing disability unrelated to relapses, Deborah Steiner, MD, of Biogen, reported during the emerging science session at the American Academy of Neurology meeting.

To assess whether it may be able to slow disability progression unrelated to relapses in secondary progressive MS, the researchers conducted the ASCEND trial in patients who'd had SPMS for at least 2 years and who had disability progression unrelated to relapses in the prior year. None of them had been previously treated with natalizumab.

A total of 887 patients randomized to placebo or 300 mg natalizumab infusion every 4 weeks for 96 weeks. While the drug was well-tolerated, the trial did not meet its primary endpoint, although a slightly smaller proportion of patients on natalizumab showed progression than those on placebo (44% versus 48%).

There was a silver lining however, as the study did show a significant benefit in upper extremity function. "There's a striking contrast between the lack of effect on ambulatory function as measured by the timed 25-foot walk test, and the effects on upper extremity function as measured by the 9-hole peg test," she said.

There are currently no approved therapies for primary progressive or secondary progressive MS -- although data on ocrelizumab, an investigational B-cell targeting therapy by Roche/Genentech, suggested the drug has some efficacy in treating PPMS.

Still, there is little to offer patients with secondary progressive disease, Steiner said. Natalizumab is highly effective in RRMS, although it carries a higher risk of progressive multifocal leukoencephalopathy (PML) than many of the other relapsing MS therapies. She added that the lack of treatment effects on ambulatory function underscores the importance of treating MS early with effective therapies like Natalizumab.