VANCOUVER -- Natalizumab (Tysabri) didn't slow disability progression in patients with secondary progressive multiple sclerosis (SPMS), researchers reported here.
The ASCEND trial missed its primary endpoint of reducing progression as measured by a composite endpoint assessing disability unrelated to relapses, , of Biogen, reported during the emerging science session at the .
But Steiner noted that there was a significant benefit on upper extremity function.
Action Points
- Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.
- Natalizumab (Tysabri) did not delay progression of ambulatory disability in secondary progressive multiple sclerosis but it was associated with significant slowing of upper-extremity disability progression and reduction of relapses and MRI activity.
- Note that natalizumab is highly effective in relapsing multiple sclerosis (MS), although it carries a higher risk of progressive multifocal leukoencephalopathy than many of the other relapsing MS therapies.
"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 reported here on ocrelizumab, an investigational B-cell targeting therapy by Roche/Genentech, suggested the drug has some efficacy in primary progressive disease.
Still, there is little to offer patients with secondary progressive disease, Steiner said. Natalizumab is highly effective in relapsing MS, although it carries a higher risk of progressive multifocal leukoencephalopathy (PML) than many of the other relapsing MS therapies.
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.
The primary endpoint was a binary outcome of confirmed disability progressors or non-progressors on a composite endpoint of Expanded Disability Status Scale (EDSS), Timed 25-Foot Walk Test (T25FW), and 9-Hole Peg Test (9HPT). This endpoint was designed to capture the treatment effects on key aspects of disability progression in SPMS, Steiner said.
A total of 887 patients randomized to placebo or 300 mg natalizumab infusion every 4 weeks for 96 weeks.
Most of the patients had advanced disability at baseline, with 63% having an EDSS score in the range of 6.0 to 6.5, and scores on the 9HPT suggested more lower-limb impairment than upper-limb.
Overall, the trial did not meet its primary endpoint, although a slightly smaller proportion of patients on natalizumab were progressors than those on placebo (44% versus 48%), she reported.
The drug did, however, show a statistically significant treatment effect on reducing upper-limb disability progression unrelated to relapse as measured by the 9HPT, with fewer progressors (15% versus 23%, OR 0.56, P=0.0012).
Natalizumab was generally well tolerated, she added, with adverse events that were consistent with its known safety profile.
Steiner concluded that while natalizumab didn't delay the progression of ambulatory disability in SPMS, it was associated with significant slowing of upper-extremity disability progression and reduction of relapses and MRI activity.
"The majority of patients had advanced disability, representing a global SPMS population for whom there is currently no effective therapy able to treat disability progression unrelated to relapses," she said.
She added that the lack of treatment effects on ambulatory function underscores the importance of treating MS early with effective therapies like natalizumab.
Disclosures
Steiner disclosed no financial relationships with industry. Co-authors reported financial relationships with several MS drugmakers.
Primary Source
American Academy of Neurology
Steiner D, et al "Natalizumab versus placebo in patients with secondary progressive multiple sclerosis (SPMS): results from ASCEND, a multicenter, double-blind, placebo-controlled, randomized phase 3 clinical trial" AAN 2016.