The study, “Improvement in Cognitive Function as Measured by NeuroTrax in Patients with Relapsing Multiple Sclerosis Treated with Natalizumab: A 2-Year Retrospective Analysis,” was published in the journal CNS Drugs.
About 40-65% of MS patients have cognitive impairment, one of the disease’s most disabling symptoms. It strongly affects patients’ quality of life, in both their personal and professional areas, and can impact their employment prospects.
NeuroTrax is a validated computerized screening test of cognition that provides a global score based on seven domains — executive function, memory, attention, visual-spatial processing, information processing speed, verbal function, and motor function.
A large-scale study using NeuroTrax showed that MS patients have poorer cognitive abilities than healthy people, particularly in areas involving information processing speed and executive function — and such problems worsen with disease duration. The test is rarely used, however, to assess treatment response in MS patients.
Tysabri, developed by Biogen, is an approved RRMS therapy that has been shown to lower MS-related disability and disease activity. It is also associated with improved cognitive function after one to three years of treatment.
Researchers collected data to evaluate Tysabri’s impact on cognitive function, assessed by Neurotrax, in 52 adults with RRMS treated at a New York center between May 2007 and August 2012. The patients, 39 women and 13 men, used Tysabri (300 mg intravenous infusion) every four weeks for at least two years.
Their mean age was 45.9 years, and 22 patients (42.3%) had a disease duration of five or fewer years while 30 (57.7%) were diagnosed at least six years ago. Tysabri was the first treatment given to 12 of these 52 patients (23.1%).
NeuroTrax data was evaluated before treatment, and one and two years after therapy initiation. A score increase of one value from baseline (pre-Tysabri treatment) was considered a clinically significant change, and a score below the mean of cognitively healthy individuals by one value was considered cognitive impairment.
Prior to starting on Tysabri, 21.2% of participants showed global cognitive impairment, with information processing speed being most affected — difficulties here were found in 39.2% of the patients analyzed.
A clinically significant improvement in overall cognitive function was detected in 21.6% of patients after one year of treatment, and 32.7% after two years. No differences were seen between treatment-naive patients and those who had taken prior therapies.
Overall, a change from baseline in global cognitive scores of 2.06 was recorded after year of treatment, and of 3.43 after two years.
Improvement were also seen in all seven cognitive domains, with significant positive changes in verbal function at one year of treatment, and in information processing speed, attention, memory, and visual-spatial processing after two years of treatment.
The greatest improvement in cognitive function after one and two years was found in information processing speed — the domain showing the greatest deficits before treatment.
Overall, the team concluded that Tysabri “significantly improved NeuroTrax global cognitive score over 2 years of treatment, regardless of whether patients were treatment-naive or were previously treated with other disease-modifying therapies.” But the researchers added that long-term studies are needed to confirm these results.
They also suggested that NeuroTrax may be useful to assess cognitive function in MS patients.
The study reported that Biogen funded this work, and three of its 11 researchers — Sourav Santra, Christophe Hotermans, and Lily Lee — are Biogen employees.