With nine biologic medications available to treat rheumatoid arthritis, it can be difficult knowing which to choose and how they compare.  Read my previous post - Biologic Medications for RA: The Big Picture - for a run-down of medications including Actemra, Cimzia, Simponi, Rituxan, Orencia, Humira, Kineret, Remicade and Enbrel.

Today, we’re comparing Actemra, Rituxan and Orencia which are medications FDA-approved for the treatment of moderate-to-severe rheumatoid arthritis.

The Immune System in RA

The exact cause of rheumatoid arthritis is unknown.  However, RA is most likely triggered by a combination of factors, one of which being an abnormal autoimmune response.  Involved in the inflammation associated with rheumatoid arthritis are B-cells and T-cells, which belong to a class of white blood cells called lymphocytes.

If the T-cell recognizes an antigen as "non-self," it will produce cytokines (such as TNF-alpha, IL-1, or IL-6) which cause B-cells to multiply and release immune proteins (antibodies). These antibodies circulate in the bloodstream, recognizing the foreign particles and triggering inflammation to rid the body of the invasion.  For reasons that are still not completely understood, both the T-cells and the B-cells become overactive in patients with RA.

What do these drugs do?

Each of these drugs interfere with the communication between cells which cause excess inflammation associated with rheumatoid arthritis.  ACTEMRA (tocilizumab) is an interleukin-6 (IL-6) receptor inhibitor.  ORENCIA (abatacept) is a selective costimulation modulator with inhibits T-cell activity.  RITUXAN (rituximab) is a monoclonal antibody therapy which binds to CD20+ B-cells and causes their destruction.

ACTEMRA, RITUXAN and ORENCIA are intended for patients who have had inadequate response from at least one TNF-inhibitor medication (such as Cimzia, Simponi, Humira, Remicade and Enbrel).  Read RA Biologics: Cimzia vs. Simponi for more information.

Dosing Schedule and Delivery

ACTEMRA, ORENCIA and RITUXAN are each given by a healthcare provider (either in your doctor’s office, an infusion center, or hospital outpatient center) through a needle placed in a vein (IV or intravenous infusion) in your arm.

For ACTEMRA, the infusion takes about one hour to give you the full weight-based dose of medicine, not to exceed 800mg per infusion.  A reduction of dosage is recommended for management of certain laboratory changes in your blood tests.  You will receive a dose of ACTEMRA about every four weeks. 

For ORENCIA, the infusion takes about 30 minutes to give you the full weight-based dose of medicine, not to exceed 1000mg per infusion.  ORENCIA infusions are repeated two weeks and four weeks after the first dose; then you will receive ORENCIA every four weeks.

RITUXAN is used in combination with methotrexate and the first infusion takes about six hours.  One course of treatment consists of two separate 1000mg IV infusions given two weeks apart.  A second course of treatment can be given 24 weeks later (six months), but no earlier than 16 weeks from the previous course.