In a global first that could transform the treatment of multiple sclerosis, Roche’s experimental humanised monoclonal antibody ocrelizumab has shown efficacy against primary progressive multiple sclerosis, while also outperforming a popular therapy for relapsing forms of the condition.

The Swiss drug giant said data from the OPERA I and OPERA II Phase III in people with relapsing MS, which affects around 85% of people at the time of diagnosis, showed ocrelizumab beat Rebif (interferon beta-1a) in reducing the three major markers of disease activity over a two-year period.

The trials showed a 46% and 47% reduction in the annualised relapse rate, as well as a 43% and 37% risk reduction in confirmed disability progression for 12 weeks compared with interferon beta-1a. On the safety side, the proportion of patients with adverse events was similar across both groups; the most common associated with ocrelizumab was infusion-related reactions (34.3% compared to 9.7% for interferon beta-1a).

In the Phase III ORATORIO trial in people with PPMS, a form of the disease marked by steadily worsening symptoms for which there is no approved treatment, ocrelizumab significantly slashed the progression of clinical disability by 24% versus a for at least 12 weeks (the primary endpoint), and by 25% over 24 weeks (a secondary endpoint).

Given that the drug is designed to selectively target CD20-positive B cells, Roche said the fact that efficacy was shown across both forms of MS “validates the hypothesis that B cells are central to the underlying biology of the disease”.

The data, which were presented at the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) this week, will be submitted to regulatory authorities early next year.