Study finds Ocrevus better than rituximab at preventing MS relapse

A study, published in JAMA Neurology has shown Ocrevus, also known as ocrelizumab, to be more effective at reducing multiple sclerosis (MS) relapses in relapsing remitting patients than rituximab. However, when it comes to disability progression outcomes between the two drugs were comparable.

Researchers wrote, ‘Study findings suggest that the effectiveness of rituximab on MS relapses was inferior to that of [Ocrevus].’ Adding, ‘The study did not find evidence for a difference in the probability of disability accumulation or improvement.’

Both drugs belong to Anti-CD20 monoclonal antibody class of drugs which work to reduce disease activity by depleting B-cells, a known type of inflammatory cell.

The group of researchers used data from two large databases – the international MSBase and the Danish Multiple Sclerosis Registry – to compare outcomes among relapsing remitting MS patients treated with the two drugs.

‘Although both therapies have similar mechanisms of action, the significantly lower cost of rituximab may motivate its preferential use despite off-label status. Whether these 2 therapies are interchangeable, however, remains an ongoing topic of debate,’ the researchers said.

This study identified 1,500 people who received one of the two drugs for at least six months between 2015 and 2021. There were some notable differences between the two groups prior to treatment, with patience showing more pronounced disability and more disease activity given rituximab.

To account for these differences, the researchers conducted matching analyses to identify people on these therapies who were similar in their pretreatment characteristics.

‘To our knowledge, the present study is the first noninferiority direct comparison of [Ocrevus] and rituximab, using rigorous methodology to mitigate group differences that allows direct comparison between therapies,’ the researchers said.

The final analysis of the data included 710 people who were given Ocrevus and 186 who were given rituximab. They were followed for an average of 1.4 years. Most of the patients had been living with MS for more than a decade and already tried two or three other therapies before being treated with an anti-CD20 treatment. The researchers did note that the findings from this analysis may not apply to the other populations, such as newly diagnosed patients starting on a first treatment.

The results showed that the average relapse rate was significantly lower for patients given Ocrevus compared with those given rituximab, which presented a 80% lower risk of relapse with Ocrevus.

The difference remained statistically significant in further sensitivity analyses and after allowing for potential unmeasured confounding variables. However, based on the Expanded Disability Status Scale scores there was no significant difference found between disability progression between the two drugs.

The researchers highlighted that this study is limited by its observational nature, and unlike clinical trials where conditions are rigorously controlled, real-world data is messier and can have undetected biases.

Clinical trials directly comparing rituximab and Ocrevus are currently taking place in Denmark, such as the Phase 3 study DanNORMS (NCT04688788).