According to an editorial, side effects need to be taken into account such as susceptibility to infections and impaired immune surveillance of new cancer cells, which could increase the risk of neoplasms. It adds that to date, infection with JC virus causing progressive multifocal leukoencephalopathy, has not been seen with B-cell depletion in multiple sclerosis, but there does appear to be a higher-than-normal risk of herpes reactivation and of neoplasms, especially breast cancer. These side effects will need to be studied in future trials and in phase 4 monitoring in the community to understand the extent of the risk.
Also in the same journal, data from another RCT (n=732) reports that use of ocrelizumab in primary progressive multiple sclerosis is linked to lower rates of clinical/MRI progression vs. placebo at 12-weeks (disability progression=32.9% vs. 39.3%; HR 0.76; 95% CI, 0.59-0.98; p=0.03). It was however associated with more frequent infusion reactions/respiratory tract infections/oral herpes.
Ocrelizumab is an investigational, humanised monoclonal antibody designed to selectively target CD20-positive B cells, which are thought to be a key contributor to myelin and axonal damage.
A licensing application is currently sitting with the FDA who has extended the review period due to submission of additional data by Genentech regarding the commercial manufacturing process of the drug.