FDA-Approved Medications: New Data
- Administered via intravenous infusion every four weeks in TOUCH program-authorized infusion centers; dose is 300 mg
- Approved for individuals with relapsing types of MS
This laboratory-produced monoclonal antibody acts against a molecule involved in the activation and function of lymphocytes (immune-system cells produced to fight infection and disease) and their migration into the central nervous system (CNS). The CNS consists of the brain, spinal cord, and optic nerves.
A small Phase II clinical trial, Natalizumab Treatment of Progressive Multiple Sclerosis (NAPMS), was performed at Copenhagen University Hospital to study the safety and efficacy of Tysabri treatment of primary-progressive MS (PPMS) and secondary-progressive MS (SPMS).1 It enrolled 24 patients and showed a reduction in markers of inflammation in the spinal fluid, as well as evidence of protection of brain tissue on modern MRI measures. This proof-of-concept study provided encouraging evidence that Tysabri may have beneficial effects in progressive forms of MS.
To continue this line of investigation, a large, randomized trial of Tysabri in SPMS called ASCEND2 evaluated the effects on the accumulation of disability in people with SPMS. There were 889 SPMS patients enrolled, the majority of whom required assistance for walking and were no longer experiencing MS relapses. Subjects were randomized to receive either Tysabri 300 mg or placebo intravenously every four weeks for 96 weeks.
The primary endpoint of the study was the percentage of patients with confirmed progression of disability according to several standardized measures. Biogen reported in a press release in October 2015 that the study did not meet its primary or secondary endpoints that relate to preventing the accumulation of disability. The data have not yet been presented in detail, but this is anticipated in 2016. It is hoped that detailed analyses of this trial may yield insight into particular groups or types of patients with progressive MS who may respond favorably to this available therapy.