The original phase III trial looked at oral laquinimod in 1106 people with RRMS. The participants were randomised to receive either once-daily oral laquinimod (0.6mg) or placebo for two years. Exploratory sub-studies using MRI measures were evaluated included white matter, grey matter and thalamic fractions at baseline, one year and two years. In addition to this, the researchers also looked at the evolution of gadolinium-enhancing and/or new T2 lesions into permanent black holes (PBH), magnetisation transfer ratio (MTR) of normal appearing brain tissue (NABT), white matter, grey matter and T2 lesions as well as NAA/Cr levels in white matter.
The researchers found that people with RRMS treated with laquinimod had lower rates of white matter atrophy at 12 and 24 months. There was less grey matter atrophy at 12 months and a trend towards less grey matter atrophy at 24 months. There was also less thalamic atrophy at one year and two years follow-up. In relation to other MRI measures, MTR decreased significantly in NABT and white and grey matter in placebo-treated people with MS but not in laquinimod-treated people with MS. The NAA/Cr was seen to increase with laquinimod. Therefore, laquinimod based on the above results may reduce some of the pathological processes in the early stages of treatment in RRMS. This may explain the observed ability of the drug to slow down disability accumulation in people with RRMS.
Authors: Filippi M, Rocca MA
Source: J Neurol Neurosurg Psychiatry. 2013 Sep 12. doi: 10.1136/jnnp-2013-306132. [Epub ahead of print]
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