The Food and Drug Administration (FDA) has approved ocrelizumab (Ocrevus), a recombinant humanized monoclonal antibody, to treat adults with relapsing or primary progressive forms of multiple sclerosis (MS). Ocrelizumab is the first drug to gain FDA approval for primary progressive MS. It is administered as an infusion every 24 weeks.

MS is a chronic autoimmune disease of the nervous system that can cause muscle weakness, damage to coordination, and paralysis. Most patients with MS have periods of remission followed by relapse. However, patients with primary progressive MS (about 15% of MS patients) generally experience a steady worsening in function, without remissions. Onset of this form of MS is usually 10 years later than that of relapsing MS, and men and women are more equally effected (in relapsing MS, women are affected two to three times as often as men). (For more information on MS, see http://www.nationalmssociety.org.)

Ocrelizumab is believed to exert its therapeutic effect by binding to CD20, a cell surface antigen found on pre-B and mature B lymphocytes, and breaking the cells apart (cytolysis). Ocrelizumab was studied in two randomized, double-blind, double-dummy, active comparator-controlled clinical trials of patients who had relapsing forms of MS. In both trials (a total of 1,656 patients), ocrelizumab was found to significantly lower the annualized relapse rate and the proportion of patients whose disability progressed at 12 weeks compared with the active drug comparator. In a third study, a randomized, double-blind, placebo-controlled trial of 732 patients with primary progressive MS, patients who received ocrelizumab had a significantly longer time before disability progression than those who received placebo.

The most common adverse effects of ocrelizumab for both forms of MS are upper respiratory tract infections and infusion reactions, which can be severe and life threatening. Other common adverse effects for those with primary progressive MS are skin infections and lower respiratory tract infections. Contraindications to ocrelizumab include active hepatitis B virus infection and a history of life-threatening infusion reactions to ocrelizumab.

Ocrelizumab must be diluted prior to administration. Nurses administering ocrelizumab via intravenous injection should premedicate patients with methylprednisolone or another corticosteroid and an antihistamine, such as diphenhydramine, before every infusion to prevent infusion reactions. Additional premedication with an antipyretic is another option. Patients should be assessed for at least one hour after infusion to confirm that no reactions have occurred.

Nurses should ensure that patients are negative for active hepatitis B viral infection-or any active infections-prior to beginning ocrelizumab. If patients require vaccination with live-attenuated or live vaccines, they should receive these at least six weeks prior to starting ocrelizumab treatment. Nurses should teach patients about the potential adverse effects of ocrelizumab, including the signs and symptoms of infusion reactions and the risk of infections. For specific information about dilution, techniques for administration, and treatment of infusion reactions, refer to the drug's label: http://bit.ly/2p19fp4.