Good Test Results for Primary-Progressive MS Drug Ocrelizumab

My neurologist tells me “the buzz is good” about ocrelizumab.

The investing web site Motley Fool calls it “the revolutionary Multiple Sclerosis drug you’ve never heard of.”

Ocrelizumab, which Genentech hopes to market under the name Ocrevus, is special because it’s designed to treat primary-progressive, as well as relapsing-remitting, MS.

How does it work?

I’m not a scientist, but after reading a lot of scientific writing here’s my best attempt to ‘splain it in “people-speak.”  (I’ve linked to some of these reports in case you want to wade through yourself).

B-cells are white blood cells that create infection-fighting antibodies. In MS patients some of these B-cells carry abnormal antibodies. Scientists believe these “rogue” B-cells play a role in the way the immune system attacks the brain and spinal cord tissues in MS patients.

Ocrelizumab binds to a molecule called CD20 on the surface of B cells and depletes those cells from the circulation. The result appears to be a reduction in MS activity while still leaving the immune system capable of fighting off infections such as PML, a very dangerous potential side effect of the current group of powerful MS drugs.

Ocrelizumab is similar to rituximab, marketed as Rituxam, in the way it works. But rituximab is a CD20 antibody that is derived from mice and humans.  Ocrelizumab is derived from humans.

Encouraging test results

Genentech recently announced encouraging results from a Phase 3 study of 732 primary-progressive MS patients.  Ocrelizumab was administered intravenously; two infusions given two weeks apart every six months. The results showed that the drug reduced the risk of disease progression, as measured by the Expanded Disability Status Scale (EDSS), by 24-25 percent compared to a placebo.  MRIs also showed a large 17 percent reducti0n in the rate of brain volume loss.

Data from two related Phase 3 studies, testing the efficacy of ocrelizumab in 1,656 patients with relapsing forms of MS, found that it was superior to interferon beta-1a, reducing the annualized relapse rate by nearly 50 percent over two-years of treatment.

What’s next?

This past February the Food and Drug Administration designated ocrelizumab a Breakthrough Therapy for use as a possible primary-progressive MS treatment.  That designation allows quicker drug development and FDA review.

Roche says ocrelizumab is the first investigational medicine to show very positive results with both primary-progressive and relapsing-remitting MS patients. The company says it plans to submit data from all three studies to the FDA this year.  If so, it’s possible there could be FDA action on the drug by the end of the year.