Moderate–high-efficacy disease-modifying therapies reduce relapse activity in late-onset multiple sclerosis, an Australian-led international study has shown.

The findings published in Neurology, Neurosurgery & Psychiatry [link here] also demonstrated a non-statistically significant trend to reduced confirmed disability progression, further supporting initial use of these therapies, the researchers said.

The multicentre cohort included 1032 participants from the MSBase registry who had symptom onset after age 50, of whom 560 received low-efficacy disease-modifying therapies (DMTs) and 472 received moderate-high-efficacy DMTs.

The total number of relapses was 105 and 248 for moderate-­high-efficacy DMT and low-­efficacy DMT, respectively, over a median follow-up time of 3.3 years and 4.2 years, respectively.

Findings showed moderate–high-­efficacy DMT use was associated with a reduction in annualised relapse rate (ARR) by 32% when compared with low-­ efficacy DMT (ARR ratio 0.68) and longer time to first relapse (HR 0.66 in favour of moderate–high-­efficacy DMT). However, relapse rates overall were low.

Results were similar when follow-­up was limited to two years (ARR ratio 0.57).

Among 856 participants with adequate follow-­up information, 37% experienced confirmed disability progression over a median of four years, with 84% of events attributable to progression independent of relapse activity, the researchers said.

Moderate–high-­efficacy DMT use reduced the hazards of confirmed disability progression and relapse-­associated worsening by 22% and 31% respectively, although neither of these findings reached statistical significance.

Dr Yi Chao Foong.

“Overall, our findings support the first-line use of moderate-high-efficacy DMT in late-onset MS, given the significant relapse reduction and trend towards reduced disability progression,” said the researchers, led by Dr Yi Chao Foong and Associate Professor Anneke van der Walt from the University of Tasmania Menzies Institute for Medical Research and Monash University, Melbourne, respectively.

“Our findings also support the notion that current high-moderate-efficacy DMTs are efficacious in preventing focal inflammation, but ineffective in reducing chronic inflammation/neurodegeneration or encouraging remyelination.

“This has significant implications for treatment strategies in late-onset MS.

“There is also a need for a more holistic approach towards preventing disability accrual in late-onset MS, such as treating comorbidities, optimising functional reserve and maximising brain health.”

The researchers didn’t examine safety data for moderate-high-efficacy and low-efficacy DMTs, but said that this would be an important addition to future studies, given the greater propensity for infections and malignancies with increasing age.