Early treatment of highly active multiple sclerosis improves outcomes, according to research sponsored by Biogen.

Researchers compared 233 patients who began natalizumab within a year of the onset of MS symptoms with 179 and 144 patients who started it one to five years and more than five years after symptoms emerged. Over three years, the likelihood of worsening on the expanded disability status scale (EDSS), which assesses MS severity, did not differ significantly between the groups.

However, the likelihood of confirmed 24-week improvement in EDSS was significantly greater for those patients who received natalizumab within a year of MS symptoms emerging (49.3 per cent) than for those treated between one to five years (38.1 per cent) or more than five years (26.3 per cent) following symptom onset.

Natalizumab reduced the annualised relapse rate by about 93 per cent in all three groups.

The authors suggest that, “disability early in the course of MS may reflect inflammation that can be mitigated by timely treatment with natalizumab, whereas later disability may be more resistant to recovery”.