UPDATE: FDA: Requires Stronger Warnings For TNF Blocker Drugs

The Food and Drug Administration said Tuesday there's an increased risk of lymphoma and other cancers associated with the use of drugs like Remicade and Humira in children and adolescents.

The agency said a new cancer-related warning will be added to the boxed-warning that's already on the drugs, which are known as tumor necrosis factor, or TNF blockers. The boxed warning, which is the FDA's strongest drug warning, currently warns of the risk of developing serious infections that can be fatal.

The drugs, which also include Enbrel, Cimzia and Simponi, are approved to treat various immune system diseases including juvenile idiopathic arthritis, rheumatoid arthritis, psoriatic arthritis, plaque psoriasis, Crohn's disease and ankylosing spondylitis. As a class, TNF blockers are among the top selling drugs in the U.S., according to IMS Health, with Enbrel and Remicade having a combined $6.5 billion of U.S. sales in 2008.

The drug labels previously discussed a possible risk of cancer. The drugs suppress the immune system by blocking TNF, a substance in the body that causes inflammation and can lead to various immune-system related diseases.

The FDA said it was working with manufacturers - including a unit of Johnson & Johnson (JNJ), which makes Remicade and Simponi, Abbott (ABT), the maker of Humira and Amgen (AMGN) and Wyeth (WYE) which co-market Enbrel - to define the risk of cancer in children and adolescents.

Cimzia, made by UCB SA's (UCB.BT), and Simponi are currently approved for use in adults. UCB was previously asked by FDA to conduct a multi-year study looking at long-term cancer risk associated with Cimzia. Last June the FDA announced it was conducting a safety review of the TNF blockers after receiving about 30 reports of cancer in children and young adults over a 10-year period who had been treated with one of the TNF blockers and other drugs like methotrexate that also suppress the immune system starting before age 18.

The agency said about half of the cancers were lymphomas, a cancer of cells in the immune system, and included both Hodgkin's and non-Hodgkin's lymphoma.

-By Jennifer Corbett Dooren, Dow Jones Newswires; 202-862-9294; [e-mail]