Lower-cost off-label Drug Rituximab Matches Ocrelizumab in Relapsing MS Trial
A randomized phase 3 study found that lower-cost off-label rituximab performed similarly to ocrelizumab for MRI disease control in newly diagnosed relapsing multiple sclerosis
For people newly diagnosed with relapsing multiple sclerosis, rituximab was noninferior to ocrelizumab in preventing new or enlarging brain MRI lesions over 2 years. The trial does not prove the drugs are identical in every way, but it gives clinicians stronger randomized evidence that rituximab may be a practical first-line anti-CD20 option where access, affordability, and payer policy matter.
Study Details
Multiple sclerosis is an immune-mediated disease in which the body attacks the central nervous system. In relapsing MS, patients can experience episodes of neurologic symptoms followed by partial or full recovery, while MRI scans may show ongoing inflammatory activity even when symptoms are quiet.
Ocrelizumab is an approved anti-CD20 therapy for relapsing and primary progressive forms of MS. Rituximab also targets CD20-positive B cells, but it has long been used off-label for MS despite being formally approved for other diseases such as certain blood cancers and autoimmune conditions.
The practical question has been whether an older, often cheaper anti-CD20 drug can deliver similar disease control to a newer approved MS therapy.
The OVERLORD-MS trial directly tested that question in newly diagnosed relapsing MS. This is important because prior comparisons between rituximab and ocrelizumab often relied on observational data, which can be affected by differences in patient selection, prior treatment history, and local prescribing patterns. The clinical trial record described OVERLORD-MS as a prospective, randomized, double-blind, multicenter noninferiority study in treatment-naïve relapsing-remitting MS patients diagnosed within the prior 12 months.
Methodology
Researchers enrolled adults in Sweden and Norway with newly diagnosed relapsing MS and recent disease activity. Participants were randomly assigned to receive rituximab or ocrelizumab every 6 months for 24 months. Patients who had already used MS disease-modifying therapy were excluded, which makes the study especially relevant to first-treatment decisions.
The primary endpoint was MRI-based: absence of new or enlarging T2-weighted lesions between months 6 and 24. This matters because MRI lesions can signal ongoing inflammatory disease activity even when a patient does not have an obvious relapse.
The study was designed as a noninferiority trial. In practical terms, the researchers were not trying to prove rituximab was better than ocrelizumab. They were testing whether rituximab was not meaningfully worse than ocrelizumab by a prespecified margin.
Key Findings
At 2 years, the estimated probability of having no new or enlarging T2-weighted MRI lesions was 92.2% with rituximab and 94.8% with ocrelizumab.
The risk difference was -2.6 percentage points, with a 95% confidence interval from -9.4 to 4.3, meeting the trial’s prespecified non inferiority criterion.
Annualized relapse rates were low in both groups, at 0.09 with rituximab and 0.04 with ocrelizumab.
Disability progression sustained for at least 6 months occurred in 3% of the rituximab group and 7% of the ocrelizumab group.
Cognitive performance profiles appeared similar between the two groups.
Infections were more common with rituximab than with ocrelizumab, occurring in 82% versus 69% of participants, but most were mild upper respiratory infections.
Serious adverse events were similar between groups, at 8% with rituximab and 7% with ocrelizumab. Serious infections were rare and occurred in four participants in each group.
Implications for Practice
For patients, the central message is not that anyone should switch therapies on their own. The message is that a lower-cost off-label option now has stronger randomized evidence behind it for newly diagnosed relapsing MS. That may matter for patients facing insurance barriers, high out-of-pocket costs, or limited access to approved branded therapies.
For neurologists, this trial strengthens the case for discussing rituximab as part of the anti-CD20 treatment conversation, especially in health systems where cost-effectiveness and access are major constraints. It also adds pressure to distinguish between regulatory approval, clinical evidence, payer policy, and real-world affordability. A drug can be off-label and still be evidence-supported, but off-label use requires careful consent, monitoring, and documentation.
The infection signal deserves attention. More patients on rituximab had infections, even though most were mild and serious infection rates were similar. In practice, clinicians still need to review vaccination status, infection history, immunoglobulin levels when appropriate, and patient-specific risk factors before starting B-cell depleting therapy.
There are also limits. Follow-up was relatively short for a lifelong disease. The trial was powered for MRI disease activity, not for rare safety events or long-term disability outcomes. Participants were mostly of Northern European ancestry, so generalizability to more diverse populations remains an important question.
The larger takeaway is that MS treatment decisions should not be driven by drug price alone, but price should not be ignored when comparable outcomes are plausible.
This trial gives patients, physicians, and payers a stronger evidence base for a more transparent conversation about value in relapsing MS care.