No Association Between MRI Measures and Primary Progressive Multiple Sclerosis

Results from clinical trials that included patients with relapsing-remitting multiple sclerosis (RRMS) do not appear to be consistent for patients with primary progressive multiple sclerosis (PPMS), according to Markus W. Koch, MD, from the University of Calgary in Alberta, Canada.

“For this study, we wanted to see how MRI measures that we often use relate to clinical outcomes,” Koch said during a session at the 31^st Congress of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS 2015) in Barcelona, Spain. Previous research on MRI measures in patients with RRMS do not match those with PPMS.

“Although MRI measures are often used in PPMS trials, their association with clinical outcomes remains uncertain,” Koch noted.

Patients collected from the PROMiSe dataset underwent MRIs at baseline and then yearly. Confirmed disability progression (CDP) was identified at 12 and 24 months using the Expanded Disability Status Scale (EDSS) and Timed 25-Foot Walk (T25FW), with a three-month confirmation period. MRI predictors were the presence of gadolinium-enhancing lesions (Gd+) and brain fraction (BF), the inverse of the normalized cerebrospinal fluid volume. Lesion volume (LV), the sum of T1 and T2 lesion component volumes, was also used as a measure.

The outcomes revealed that a significant amount of people had disability progression. The EDSS determined that it rose 19.8% after 12 months and 30.1% after 24 months. The T25FW also showed increasing results with 29.7% disability progression after 12 months and 43.3% after 24 months.

“Baseline EDSS and T25FW were associated with CDP at 12 and 24 months in all models,” Koch verified.

At baseline, 14% of patients had lesions and that percentage did not change very much over time. Brain volume, on the other hand, had an average loss of 2.5% after two years.

“Interestingly though, neither lesion load or brain volume is associated with disease worsening,” Koch divulged. Meaning that the change in lesion load and brain volume did not influence the risk of CDP. However, factors that did predict worsening disability progression was age and being male both one and two years into the study.

These findings indicate that unlike RRMS, there is not an association between MRI measures and PPMS disability progression. At the end of the presentation, an audience member asked if the failed association could have something to with the available imaging tools.

“We definitely need better imaging in the spinal cord,” Koch concluded.