Cancer risk from arthritis drugs overstated-study
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Two biotech drugs used to treat rheumatoid arthritis—Abbott Laboratories Inc.‘s Humira and Johnson & Johnson’s Remicade—may raise the risk of cancer and infections but not as much as was feared, researchers said on Tuesday.
A series of letters published in the Journal of the American Medical Association show that several teams have taken a fresh look at the safety of the two drugs and find that they may double the risk of cancer and infections.
Most of the researchers, and the U.S. Food and Drug Administration, agree that patients need to know about the risks but say the benefits mean the drugs should stay on the market.
In May, a study published in the Journal showed that Humira, known generically as adalimumab, and Remicade, known generically as infliximab, tripled the risk of cancer and some infectious diseases such as tuberculosis in patients who used them.
This information had already been included in labels put on the drugs after a directive from the FDA six months earlier.
Dr. Eric Matteson and colleagues at the Mayo Clinic in Rochester, New York, who did the study published in May re-analyzed the data and added more data from other studies they had not considered before.
“We re-did the analysis completely,” Matteson said in a telephone interview. The new analysis showed the cancer risk was 2.4 times greater among patients who used the drugs, and the risk of infectious disease was 1.8 times greater.
“The magnitude is still higher in treated groups than in untreated groups,” Matteson said.
This would be expected. Rheumatoid arthritis is an autoimmune disease, in which the immune system mistakenly attacks the joints. The drugs target TNF-alpha, one of the immune system’s signaling compounds.
“Anything that modifies our immune systems does have the potential for causing cancers,” Matteson said.
His team is looking at a third drug in the same class, Amgen’s Enbrel, known generically as etanercept. “We don’t have data yet,” Matteson said. “We do think that there’s a concern, which is why we are looking.”
So far, studies have shown no link between Enbrel and cancer or infectious diseases.
Rheumatoid arthritis affects about 2 million Americans and represents a rapidly growing market that could reach more than $11 billion by 2014, according to market research company Research and Markets.
Drugs approved to treat it also often work against skin conditions such as psoriasis, ulcerative colitis and similar autoimmune conditions.
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