Rheumatoid Arthritis Drugs' Role in Infections, Cancer

New meta-analysis of previous studies confirms the link.

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Arthritis drugs and cancer. Steve Sucsy / Getty Images

Humira And Remicade Linked To Serious Infection And Cancers

Rheumatoid arthritis patients being treated with either Humira (adalimumab) or Remicade (infliximab) have three times the risk of developing certain cancers and twice the risk of developing serious infections. Mayo Clinic researchers, led by Eric Matteson, M.D. reported the study results in the May 17 issue of Journal of the American Medical Association (JAMA).

The aforementioned conclusions were drawn following a meta-analysis of previous studies. Besides the triple risk for developing cancer and twice the risk for developing serious infection, it was concluded that cancers were much more common in rheumatoid arthritis patients treated with high doses of TNF blockers.

Be Aware Of Possible Complications With TNF Blockers

Over a half million patients have been treated with TNF blockers, many very successfully. The benefit seen by many patients is undisputable but researchers also believe patients and health care providers must be aware of the possible complications.

The study involved:

  • a search of literature for trials of TNF-blocking antibodies for rheumatoid arthritis.
  • searching abstract databases of ACR meetings and EULAR meetings.
  • interviewed manufacturers of Remicade and Humira.
  • 9 trials involving 3,493 patients who received TNF blockers (29 cancers found) vs. 1,512 patients who received placebo (3 cancers found).

    Serious infections, including cellulitis and pneumonia, were found in 126 patients on TNF blockers and 26 on placebo.

    What Causes The Increased Risk Of Infection And Cancer?

    The lead researcher, Dr. Matteson reportedly suggested that the increased risk of infection and cancer may be due to the drugs interference with immunological mechanisms which are vital to fighting infection as well as the body's normal ability to recognize cancer cells.

    Rheumatoid arthritis patients are known to have twice the risk of serious infection as healthy individuals. Taking TNF blockers increases the risk even more. Therefore, Dr. Matteson considers the additional risk from TNF blockers to be moderate. It should be noted that Enbrel (etanercept) was not included in this study.

    TNF blockers should not be abandoned, according to Dr. Matteson, because so many rheumatoid arthritis patients benefit from the treatment. Matteson believes patients on TNF blockers have a responsibility:


    • A spokesperson from Abbott, the maker of Humira, stated the studies were too short to monitor cancer incidence.
    • A spokesperson from Centocor, the maker of Remicade, stated that most of the analyzed studies used higher than recommended doses of Remicade.
    • Also, reports of a correction published in JAMA with regard to incorrect statements on funding/support and the role of sponsors as well as incorrect and incomplete financial disclosures. Do these errors and omissions impact the validity of the report? JAMA has requested that Mayo Clinic College of Medicine conduct an investigation.

      Related Resources - TNF Blockers / Biologic DMARDs

      Related Resources - Rheumatoid Arthritis

      Sources: Rheumatoid Arthritis Drug Linked To Serious Infections And Cancers, Newswise; Anti-TNF Antibody Therapy And Adverse Events, JAMA, May 17, 2006; Cancer Risks Detailed For Arthritis Drugs, AP, May 16, 2006

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