The US Food and Drug Administration (FDA) has just announced an investigation into the link between certain drugs known as tumor necrosis factor (TNF) blockers and the development of cancer in children and young adults taking these medications.  TNF blockers are routinely prescribed to children aged 18 and younger to treat conditions such as Juvenile Idiopathic Arthritis (JIA), formerly known as Juvenile Rheumatoid Arthritis (JRA), Crohn’s disease, and other diseases of the immune system.

There have been almost 30 reports of children and young adults developing cancer after a history of taking TNF blockers since they were first approved for use in 1998.  The young people who developed cancer were taking other immunosuppressant medications in addition to the TNF blockers.  Some of these additional medications include 6-mercaptopurine, azathioprine, and methotrexate.

Two forms of TNF blocker, marketed under the brand names Enbrel and Humira, are approved for treatment of JIA in children.  Remicade has met FDA approval for the treatment of Crohn’s disease in children.  A fourth TNF blocker, Cimzia, is approved for adult use only.

In the body, TNF is known to cause inflammation that can lead to diseases of the immune system, such as JIA and Crohn’s disease.  TNF blockers work with the immune system to block the action of TNF.

Of the children developing cancer in conjunction with TNF use, about half the cancers have been lymphomas, including both Hodgkin’s and non-Hodgkin’s-type lymphomas.  Lymphomas are cancers that strike the cells of the immune system and are not known to be generally associated with either JIA or Crohn’s disease.

Other cancers reported in children taking TNF blockers include melanoma, leukemia, and attacking the solid organs of the body.

The FDA investigation is expected to continue for at least 10 years.  Since cancer often takes many years to develop, studies of shorter duration may not be as conclusive as the long-term investigation the FDA has under way.

At this time, the FDA urges parents and physicians to continue to use the TNF blockers as prescribed.  It is the agency’s belief that the potential benefits of taking the TNF blockers outweigh the risk of developing cancer.