The drugs already carry a black-box warning that they may cause cancer. But the FDA now says the warning labels must highlight the drugs' possible risk of lymphoma and other cancers in children and teens.
TNF blockers neutralize a protein, tumor necrosis factor alpha, that is overproduced in inflammatory diseases. The drugs are used to treat juvenile rheumatoid arthritis, juvenile idiopathic arthritis (JIA), psoriatic arthritis, psoriasis, Crohn's disease, ankylosing spondylitis, and other autoimmune diseases.
TNF, however, has a normal function in the body: fighting cancer.
In a June 2008 alert, the FDA announced that it was investigating the link between TNF blockers and cancer in children and teens. That investigation, now complete, identified 48 cases of malignant cancers in children and teens and 147 cases of leukemia in all patients (including adults) taking TNF blockers.
Eleven children and teens died of lymphoma or complications of treatment; 26 of the 30 deaths among leukemia patients were linked to TNF blockers.
Because immune diseases themselves raise cancer risk, and because most patients take other immune-suppressing drugs along with TNF blockers, the FDA cannot say for sure that the TNF blockers definitively caused the cancers.
But the agency warns doctors and patients to be aware of the risk and to be on the lookout for any early signs of cancer.
The FDA investigation also links the TNF blockers to new-onset psoriasis that sent some patients to the hospital. Most patients improved after they stopped taking the drugs.