Real-world efficacy of natalizumab and B-cell depleting therapies in relapsing forms of MS are incompletely understood — especially when used as first line therapy.

Clinical trials of natalizumab and B-cell depleting therapies (ocrelizumab, rituximab, ofatumumab) have demonstrated that these drugs are highly effective in preventing relapses and new MRI lesions and moderately effective in slowing down disease progression over a two-year period.  

This was an IRB approved retrospective chart review from The Brown Neurology Multiple Sclerosis Center between 2007-2021. 

This study included 162 patients (N=75, B=87) with an average age of 38.5 years. Patients were followed for an average of 2.4 years (range:0.1-9.5). 14 (8.6%) patients had a confirmed relapse (N= 10, B=4) with an annualized relapse rate of 0.03. 17 (10.5%) patients had changes on MRI when compared to baseline MRI (N=14, B= 3). 6 had symptoms corresponding to MRI changes while 11 were asymptomatic. The average baseline EDSS score was 2.47 (range: 0-7) which decreased to an average EDSS of 1.97 (range: 0-6.5) after treatment. The EDSS score remained stable or improved in 144 patients (88.8%). The NEDA rate was 45.1%% (73 patients, N=30, B=43). 19 natalizumab patients (25.3%) discontinued treatment while all ocrelizumab patients remained on treatment. 11 (14.7%) natalizumab patients seroconverted to JCV antibody positivity. Of these, 9 of 11 patients switched to other therapies. 4 natalizumab patients developed anti-natalizumab antibodies. There were no serious adverse events.

As first line therapies, both natalizumab and B-cell depleting therapies are highly effective in preventing relapses, MRI lesions and slowing disability progression with no significant or serious adverse events. B-cell depleting therapy treated patients are more likely to remain on treatment when compared to natalizumab treated patients.