Summary
Health Canada has recently approved a new drug for relapsing-remitting multiple sclerosis called Ocrevus (ocrelizumab). Developed and marketed by pharmaceutical company Roche, the drug is administered via intravenous infusion and targets white blood cells called B cells, which are believed to be involved in the abnormal immune response in MS. Ocrelizumab binds to CD20, found on the surface of B cells, and causes cell lysis (breaking down of a cell) leading to a dose-dependent depletion of B cells.
Clinical Trials
The approval was based on results from two pivotal phase III clinical trials called OPERA I and OPERA II. OPERA I and II were double-blind, double-dummy trials which compared the effects and safety of ocrelizumab (300 mg infusions on Days 1 and 15 for the first dose followed by single infusions of 600 mg for all subsequent infusions every 24 weeks) to the approved disease modifying therapy (DMT) interferon beta-1αor Rebif (44 µg three times a week) for 96 weeks. Clinical outcomes from 1,656 participants enrolled showed a 46% and 47% reduction in the annualized relapse rates with ocrelizumab compared to interferon beta-1 α at 2 years in OPERA I and OPERA II, respectively. Secondary outcomes showed ocrelizumab had a 40% lower risk of disability progression at 24 weeks compared to interferon beta-1α in a pooled analysis of OPERA I and OPERA II. From week 24 to 48, the number of lesions was 94% lower in the ocrelizumab group vs the interferon group in OPERA I and 96% lower in the ocrelizumab group than in the interferon group in OPERA II trial. From week 48 to week 96, the number of lesions was 98% lower and 97% lower in the ocrelizumab group than in the interferon beta-1a group in the OPERA I and the OPERA II trail, respectively.
In terms of safety, more people who were treated with ocrelizumab had infusion-related reactions compared to those who received interferon beta-1α, including itchy skin, rash, throat irritation, and flushing.
Comment
Today, with the approval of ocrelizumab, there are 14 disease-modifying therapies available for Canadians who are diagnosed with relapsing forms of MS. Having a range of treatment options available enables individuals to select a regimen that accommodates their needs and lifestyles. Selecting an MS therapy should be done in consultation with a health care team. The MS Society of Canada will provide updates on availability and public coverage of ocrelizumab as they become available.
For more information on ocrelizumab, check out the ocrelizumab FAQ.