Ocrevus (Ocrelizumab): The New MS Therapy

Newly Approved MS Therapy for Relapsing and Primary-Progressive MS

Nurse injecting medicine into IV bag
Ocrelizumab: An MS Drug in the Pipeline. Echo/Getty Images

The monoclonal antibody Ocrevus (ocrelizumab) is FDA-approved for treating both primary progressive MS and relapsing types of MS. This is a huge MS breakthrough, as there is currently no other medication for treating people with primary progressive disease.

What Is Ocrevus?

Ocrevus (ocrelizumab) is a humanized monoclonal antibody that selectively binds to a molecule called CD20, which lies on the surface of B cells (a type of immune system cell). By binding to CD20, the number of B cells is decreased in a person's bloodstream.

Since B cells play a role in myelin sheath loss and damage in multiple sclerosis, depleting these particular B cells has been shown to reduce MS disease activity. That being said, because Ocrevus only targets B cells, other cells within the immune system (like T cells) remain intact, helping to maintain a person's immune function.

Ocrevus in Phase III Trials MS

Ocrevus was examined in three phase III trials for treating both relapsing MS and primary progressive MS. In two trials, Ocrevus was compared to Rebif for treating people with relapsing-remitting MS. Since there is currently no FDA-approved medication for primary-progressive MS, Ocrevus was compared to placebo in that trial.

A little reminder—while phase II trials examine the safety and benefit of a drug, phase III trials are larger and compare the drug to the standard of care drug.

Treating Relapsing MS With Ocrevus

In the two phase III trials of people with relapsing MS, over 1600 participants were randomized to receive either an Ocrevus infusion every six months or Rebif (interferon beta-1a) three times weekly for 96 weeks (nearly two years). Rebif is a subcutaneous injection, meaning it is given underneath the skin with a thin needle.

Results revealed that the yearly relapse rate was 46 to 47 percent lower in the participants who received Ocrevus than in the participants who received Rebif.  In addition, the progression of the participants' disability was measured at both 12 weeks and 24 weeks using the EDSS scale.

In both time frames, the participants who received Ocrevus had lower disability progression than those who received Rebif.

Also, there were 94 to 95 percent less gadolinium-enhancing lesions on MRI in the Ocrevus group than the Rebif group.

Adverse effects in these two trials included:

  • Infusion-related reactions in the Ocrevus group (in a little over a third of the participants): like rash, flushing, or itchiness
  • Serious infections occurred in 1.3 percent of those in the Ocrevus group and 2.9 percent in the Rebif group
  • New, abnormal tissue growths (called neoplasms) occurred in 0.5 percent of those in the Ocrevus group and 0.2 percent in the Rebif group.

Treating Primary-Progressive MS With Ocrevus

In a phase III trial of Ocrevus in primary-progressive MS (PPMS), over 700 participants received either Ocrevus or a placebo infusion every 6 months for at least 120 weeks.

Results revealed that at 12 weeks, there was a 24 percent reduction in confirmed disability progression in the participants who received Ocrevus, as opposed to those who received the placebo infusion. At 24 weeks, the confirmed disability progression was reduced 25 percent in the participants who took Ocrevus.

Ocrevus was also found to decrease the time it took for participants to walk 25 feet by nearly 30 percent when compared to the placebo infusion.

On brain MRI, after 120 weeks, there was 3.4 percent less total volume of T2-hyperintense brain lesions in the Ocrevus group versus 7.4 percent more lesions in the placebo group.

In terms of adverse effects, the Ocrevus group had more infusion-related reactions, upper respiratory tract infections, and oral herpes infections. The infusion-related reactions (like rash, itching, flushing, and throat irritation) were more common after the first infusion and improved with next doses.

Serious infections occurred in 6.2 percent of the Ocrevus group and 5.9 percent of the placebo group—so similar in both groups. The researchers carefully defined what a serious infection was—an infection that was fatal, life-threatening, required hospitalization, resulted in disability, or required medical intervention (like intravenous antibiotics) to prevent death or disability.

It's interesting to note that there were more neoplasms in the Ocrevus group (like breast and skin cancer) than the placebo group. It's unclear why this is the case and warrants further investigation.

A Word From Verywell

Ocrevus (ocrelizumab) is the first FDA-approved medication to treat primary progressive MS, which affects approximately 10 to 15 percent of people with MS, so this is extremely exciting and hopeful. Of course, it is exciting too for those with relapsing types of MS, as many people have continued to develop relapses despite current MS treatments. Ocrevus now provides them with another option.

This all being said, it's important to remember that choosing the right MS treatment for you is a delicate and individualized process. In addition, the results of the three trials on Ocrevus do not predict how you will respond to the medication.

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Article Sources
  • Hauser SL et al. Ocrelizumab versus Interferon Beta-1a in relapsing multiple sclerosis. N Engl J Med. 2016 Dec 21.
  • Montalban X et al. Ocrelizumab versus placebo in primary progressive multiple sclerosis. N Engl J Med. 2016 Dec 21.
  • Sorensen PS, Blinkenberg M. The potential role for ocrelizumab in the treatment of multiple sclerosis: current evidence and future prospects. Ther Adv Neurol Disord. 2016 Jan;9(1):44-52.