Gilenya's Impact on Cognitive Function and Thalamic Volumes

Cognitive impairment is a well-recognized manifestation of multiple sclerosis (MS) with prevalence estimates ranging from 43 to 70%. It is also known to occur as early as the first demyelinating event and is a major factor contributing to quality of life in MS. Treatment strategies for cognitive impairment in MS are limited. Several agents have been tested as therapeutics for MS-related cognitive dysfunction and have showed no major benefit. Cognitive rehabilitation has shown some promise, but the data are limited and many studies have suffered from methodological shortcomings. Given the lack of well-established treatment options and the substantial impact of cognitive impairment, protection of cognitive function from the earliest stages of the disease is of great importance. Cognitive outcomes received relatively little attention in the pivotal studies of MS disease modifying therapies (DMT), but some data suggest that DMT may have a positive impact on cognition. Gilenya is of special interest because it was found to have a significant protective effect on whole brain atrophy when compared against placebo and intramuscular interferon β-1a in two phase III studies, showing a 31-35% reduction in percentage brain volume change. Gilenya's effect on whole brain atrophy leads to the natural hypothesis that it may have a beneficial effect on cognitive function in MS. Also of particular interest is the extent to which protection of the thalamus and cortex contributes to Gilenya's effect on whole brain atrophy and possible effects on cognition. The study will enroll 15 subjects from the Cleveland Clinic Mellen Center patient population. Participants must have been on Gilenya for at least 6 months at the time of study entry. The study will involve three assessments: at baseline, six months, and one year. At each time point, participants will undergo 7T MRI of the brain with and without contrast. Participants will also undergo a battery of neurometric testing at each time point. The tests will include the Brief Visuospatial Memory Test - Revised (visuospatial skills), the iPadTM Processing Speed Test (processing speed), the Selective Reminding Test (verbal learning and memory), and the Delis-Kaplan Executive Function System Sorting Test (problem-solving skills; can only be administered at baseline and one year due to version limitations).