Ocrelizumab can be effective in treating patients with relapsing-remitting multiple sclerosis (RRMS) who showed suboptimal responses to other disease-modifying treatments, according to results of the CHORDS clinical trial published in the Multiple Sclerosis Journal.

During the trial, 576 patients with RRMS, aged 18 to 55 years, who had a suboptimal response to another disease-modifying treatment after a period of 6 months or more were treated with ocrelizumab at a dose of 600 mg every 24 weeks. A suboptimal response was defined as 1 clinically reported relapse and/or lesion activity. 

The primary outcome measures of the trial were no evidence of disease activity and no infusion-related reactions. No evidence of disease activity was defined as the absence of protocol-defined relapses, confirmed disability progression, and T1 gadolinium (Gd)-enhancing lesions and new/enlarging T2 lesions on brain magnetic resonance imaging (MRI).

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The results showed that almost half of the patients (48.1%) showed no evidence of disease activity over 96 weeks of ocrelizumab treatment. Most patients (89.6%) were free from a protocol-defined relapse. The same percentage of patients were free from confirmed disability progression. Almost all patients (95.5%) were free of T1 Gd-enhancing lesions, and 59.5% had no new or enlarging T2 lesions.

“Consistent efficacy of [ocrelizumab] on clinical and magnetic resonance imaging (MRI) disease activity measures and progression was shown in patients with RRMS and a suboptimal response to prior [disease-modifying treatments],” the researchers wrote. They also reported that “no new safety signals were observed” during the trial. 

Suboptimal response to a certain disease-modifying therapy is common in MS. The reason for this may vary between patients. It is important to switch these patients to a more effective option before significant neurological damage occurs; only then can disease progression be minimized and long-term outcomes optimized. 


Weinstock-Guttman B, Bermel R, Cutter G, et al. Ocrelizumab treatment for relapsing-remitting multiple sclerosis after a suboptimal response to previous disease-modifying therapy: a nonrandomized controlled trial. Mult Scler. Published online August 12, 2021. doi:10.1177/13524585211035740

A study of ocrelizumab in participants with relapsing remitting multiple sclerosis (RRMS) who have had a suboptimal response to an adequate course of disease-modifying treatment (DMT). ClinicalTrials.gov. December 22, 2015. Updated May 26, 2020. Accessed August 18, 2021.