This study is a Phase II placebo-controlled, double-blind study,
looking at the safety and efficacy of Lisdexamfetamine dimesylate (LDX)
in people with MS with cognitive impairment.
LDX is an inactive
amphetamine prodrug which is currently approved for attention deficit
disorder. Patients included in the study had clinically definite MS and
impaired on either of two primary outcomes: the Symbol Digit Modalities
Test (SDMT) or the Paced Auditory Serial Addition Test (PASAT). Both are
measures of cognitive processing speed.
Secondary outcomes were
the Brief Visuospatial Memory Test Revised (BVMTR), the California
Verbal Learning Test 2nd edition (CVLT2). Both of these are measures of
episodic memory. Also included was a self-report measure of executive
function using the Behavoiural Rating Invenory of Executive Function for
Results showed that there was significant
improvement in the SDMT and CVLT2 score in the LDX group when compared
to the placebo group. There was a high proportion of adverse events
reported in both the LDX-treated and placebo-treated subjects. This
study suggests an improvement in processing speed and memory in
cognitively impaired MS patients.
Further studies are needed as
this data is based on a small sample size and the treated and nontreated
groups were not optimally balanced on all outcomes at baseline.
Authors: Morrow SA, Smerbeck A, Patrick K
Source: J Neurol. 2012 Sep 23. [Epub ahead of print]
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