Biosimilar Truxima Works as Well as Rituximab Originator in MS, Study Finds
Rituximab — marketed as Rituxan in the United States — is an antibody-based therapy that works by killing B-cells, which are immune cells that drive inflammation in MS and other conditions. While not approved for MS itself, rituximab is used off-label as an MS treatment. It is marketed in Europe by Roche as MabThera, with other brand names used elsewhere in the world.
The study, “Comparison of rituximab originator (MabThera) to biosimilar (Truxima) in patients with multiple sclerosis,” was published in the Multiple Sclerosis Journal.
As patents have expired, biosimilars of rituximab have emerged. Biosimilars are therapies that are highly similar to its originator treatment, and have no clinically meaningful differences from an existing approved reference product.
Researchers in France now have directly compared the rituximab biosimilar Truxima to MabThera (rituximab originator) as a treatment for MS.
The team used data from people with MS treated with rituximab off-label at the University Hospital Timone in France from December 2015 to June 2018.
Individuals treated up to October 2017 (105 people) received MabThera, while those treated after that date (40 people) were given Truxima. There were no significant differences between the two groups in terms of sex, age, disability, MS types, and other clinically relevant factors.
All participants were followed up for one year, and outcomes were compared between those given the originator or the biosimilar. Not all individuals had data available for every time point.
Results showed that, at both six months and one year after starting treatment, the numbers of B-cells in patients’ blood were not significantly different between the two groups.
Similarly, the amount of inflammation in the brain, as assessed through magnetic resonance imaging (MRI), did not differ significantly between the two treatment groups.
Among participants with relapsing-remitting MS (RRMS, 72 in the MabThera group, and 22 in the Truxima group), the annual relapse rate did not differ significantly based on treatment; on average, relapse rates were 0.02 per year with MabThera, and 0.025 per year with Truxima.
In addition, the disability scores, as assessed through the expanded disability status scale (EDSS), were stable in both groups during the follow-up period.
The safety profiles of MabThera and Truxima also were similar. No patient had a serious reaction to treatment, and no infusion was incomplete. The most common adverse side effects were infusion-related side, such as skin rashes and throat irritation — 4.8% with MabThera, and 5% with Truxima.
During follow-up, the most common non-infusion-related side effects were urinary infections (15.5% with MabThera, and 10% with Truxima), and physical weakness (6.7% with MabThera, and 15% with Truxima). None of the patients showed severe or opportunistic infections, and no patients discontinued rituximab treatment after one year.
Overall, the team concluded that the “efficacy and safety of the rituximab biosimilar Truxima seem equivalent to the originator MabThera in MS patients,” they wrote.
The team suggested that “Truxima could represent a relatively cheap and safe therapeutic alternative to MabThera, and could help improve access to highly-efficient therapy for MS in low- or middle-income countries.”
Notably, Teva and Celltrion, the manufacturers of Truxima, were not involved in this study.