Authorities in the United States are investigating certain types of drugs used to treat arthritis and other conditions.
The Food and Drug Administration (FDA) is concerned that a class of drugs called Tumor Necrosis Factor (TNF) blockers may be linked to cancer.
The agency has received 30 reports in the last decade that the drugs caused cancer in children and young adults.
TNF blockers work by suppressing the immune system by blocking the activity of TNF, a substance in the body that can cause inflammation and lead to immune system-related diseases.
Arthritis, usually thought to be a problem only affecting older people also affects children and young people and it is the use of the drugs in the young that has raised the concern.
The reports are of cancer occurring in children and young adults who began taking TNF blockers when they were ages 18 or less, to treat Juvenile Idiopathic Arthritis (JIA), Crohn's disease or other diseases.
Half the cancers were lymphomas and included both Hodgkin's and non-Hodgkin's lymphoma - lymphoma is a cancer of the cells in the immune system and is not a recognized complication of JIA or of Crohn's disease.
Other cancers reported included leukemia, melanoma, and solid organ cancers.
The FDA says while cancers are known to occur in children and young adults, the reports of these events in children and young adults receiving TNF blockers are of concern and deserve further investigation.
The four TNF drugs causing concern are Remicade, Enbrel, Humira, and Cimzia - they reduce the signs and symptoms of arthritis and Enbrel is used in patients from age 2 and up.
They are each approved to treat one or more of a number of immune system diseases including JIA, rheumatoid arthritis, psoriatic arthritis, plaque psoriasis, Crohn's disease, and ankylosing spondylitis.
The drug companies say the FDA has been aware of the possible association between the use of TNF blockers and the development of cancers, since the prescribing information for all four TNF blockers warns about the possible risk of cancer.
The FDA has asked the makers of the TNF blockers approved for use in children (Remicade, Enbrel, and Humira) to provide information about all cases of cancer reported in children taking TNF blockers.
The makers of Cimzia will also conduct a decade long study starting in 2009 to assess long-term risks of the product, including lymphoma and other cancers.
The FDA says at present it believes that the potential benefits of the use of TNF blockers outweigh the potential risks in certain children and young adults having one of the diseases for which the TNF blockers are approved to treat.
The FDA urges both healthcare professionals and patients to report side effects from the use of Remicade, Enbrel, Humira, and Cimzia, to the FDA's MedWatch Adverse Event Reporting program.