How Does Orencia Differ From TNF Blockers?

Not All Biologic Drugs Are the Same

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Question: Orencia vs. TNF Blockers - What's the Difference?

How is Orencia (abatacept) different from TNF blockers? What is its mechanism of action? Who is a candidate to successfully use Orencia? Is it prescribed for patients before they have tried or failed other biologics?

Answer:

Orencia (abatacept) for Rheumatoid Arthritis

Orencia (abatacept) was approved by the U.S. Food and Drug Administration (FDA) on Dec 23, 2005 as the latest drug to treat the signs and symptoms of rheumatoid arthritis.

Orencia joined three other biological DMARDS at the time in slowing the progression of structural damage, including the tumor necrosis factor antagonists (anti-TNF drugs):

Simponi (golimumab) and Cimzia (certolizumab pegol), two more TNF blockers, were approved later.

Orencia is approved for moderately to severely active rheumatoid arthritis patients who have had an inadequate response to one of the disease modifying drugs (DMARDs) which in addition to the TNF antagonists include:

How Is Orencia (abatacept) Administered?

Similar to Remicade (infliximab), Orencia is given as an intravenous infusion (IV). Orencia though is administered over 30 minutes, unlike infliximab which is administered over about 2 hours.

Following the initial administration, Orencia is given at 2 and 4 weeks, then every 4 weeks thereafter.

Orencia may be used as monotherapy (alone) or concomitantly with other DMARDS that are not TNF antagonists due to an increased risk of toxicity with the combination.

As of July 2011, a subcutaneous self-injectable formulation of Orencia was approved by the FDA.

What Side Effects Are Associated With Orencia (abatacept)?

Side effects include but are not limited to:

  • allergic reactions that rarely can be life threatening
  • infection
  • respiratory problems (especially in patients with underlying chronic obstructive pulmonary disease and malignancies)

Facts to Consider Before Trying Orencia (abatacept)

The cost of Orencia including its monitoring is most likely more than the injectable TNF antagonists adalimumab and etanercept but less than infliximab. Orencia has shown only mild benefit when used alone so it is best prescribed with another DMARD such as methotrexate or others to achieve optimal results.

In my practice, until there is more clinical experience with Orencia, I plan to reserve it for patients who have failed (side effects or lack of benefit) at least two out of the three TNF antagonists, due to the fact that these arthritis drugs have been on the market since etanercept was introduced in 1999 and demonstrate a favorable benefit-risk ratio.

Comparing Orencia to Anakinra

Anakinra is seldom used to treat rheumatoid arthritis due to its need for daily injections and the limited benefit compared to the TNF antagonists which block the activity of TNF (a cytokine or messenger between cells).

TNF is a compound that has a key role in causing the inflammation and damage in rheumatoid arthritis.

T cells also play a role in causing the clinical signs and symptoms of rheumatoid arthritis. Orencia blocks the signal in the blood that is necessary for T cells to due their damage. Kineret (anakinra) blocks the cytokine IL-1 which plays a role in the damage to bone that is part of rheumatoid arthritis.

Answer provided by Scott J. Zashin, M.D., clinical assistant professor at University of Texas Southwestern Medical School, Division of Rheumatology, in Dallas, Texas. Dr. Zashin is also an attending physician at Presbyterian Hospitals of Dallas and Plano. He is a fellow of the American College of Physicians and the American College of Rheumatology and a member of the American Medical Association.

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