NEWS: Rheumatoid Arthritis Drugs May Not Raise Cancer Risk - Forbes.com

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Rheumatoid Arthritis Drugs May Not Raise Cancer Risk

08.31.06, 12:00 AM ET

THURSDAY, Aug. 31 (HealthDay News) -- Concerns that rheumatoid

arthritis drugs called TNF blockers and related medications could

cause cancer appear to be unfounded, a new study shows.

Rheumatoid arthritis sufferers do tend to have higher rates of cancer

than people without the autoimmune illness. But a team of U.S. and

Canadian researchers found no increased risk for cancer among

patients using drugs such as TNF blockers compared to those using

other medications.

However, cancer can develop over decades, and the drugs in question

have only been around for a few years, the experts noted. They also

said it's difficult to determine what's driving the higher rates of

cancer seen in rheumatoid arthritis patients -- the drugs they take

or the illness itself.

In any case, medications such as tumor necrosis factor (TNF)

antagonists remain " amazing drugs " for easing arthritis symptoms,

said Dr. Harminder Sikand, a pharmacist at Scripps Mercy Hospital in

San Diego. He was not involved in this study.

TNF blockers include infliximab (Remicade), etanercept (Enbrel), and

adalimumab (Humira). The drugs work by dampening down the immune

system, which becomes hyperactive in patients with rheumatoid arthritis.

An estimated two million Americans have the disorder, where chronic

inflammation leads to joint damage, pain, and stiffness.

Scientists have long noticed a connection between cancer --

especially leukemias and lymphomas -- and autoimmune diseases like

rheumatoid arthritis, explained another expert, Dr. Clifton O.

Bingham III, assistant professor of medicine at the s Hopkins

University Arthritis Center.

But the reasons behind the arthritis-cancer link have remained

unclear, Bingham said. One prevalent theory: Anti-arthritis drugs

like TNF blockers might allow cancer to occur because they suppress

the immune system's ability to fight off tumors.

" When we think we come in with these [pharmaceutical] magic bullets,

we may be knocking out something that we need, " Bingham said.

Earlier this year, a review of research suggested that the risk of

cancer was 3.3 times higher in patients who took TNF-blockers

compared to those taking a placebo. The overall risk of any one

patient developing cancer remained very small, however.

According to that review, 154 people would need to be treated with

one of the drugs for each single person who would go on to develop

cancer within six to 12 months.

In the new study, researchers from Harvard Medical School, Boston,

and the University of British Columbia, in Vancouver, examined the

medical records of 1,152 people who took TNF-blockers or a related

drug called anakinra (Kineret), as well as 7,306 who took another

rheumatoid arthritis drug, methotrexate (brand named Rheumatrex and

Trexall).

An estimated 70 percent of rheumatoid arthritis patients are on

methotrexate, Bingham said.

Reporting in the September issue of Arthritis & Rheumatism, the

researchers concluded that users of TNF-blockers and related

medications are " unlikely " to have a significantly higher risk of

cancer than those who take methotrexate.

While the study results are encouraging, Bingham said they aren't the

" final word " on the subject.

It's possible that longer-term studies may still reveal higher cancer

rates, said Bingham, who's received funding from companies that are

developing TNF blockers.

What should patients do? Sikand, the pharmacist, suggested they

consider the potential costs and benefits of the drugs.

The benefits can be great, Sikand said. " For those who are afflicted

by this disease, these drugs have changed their lives. They're able

to have a normal life. "

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