ACR: No Cancer Link Found with New Rheumatoid Arthritis Agents

WASHINGTON, Nov. 15 -- There is no link of significance between major cancers and new biologic therapies for rheumatoid arthritis, FDA-mandated warnings not withstanding, a researcher said here.

"The bottom line is that, in general, these drugs are safe," said Fred Wolfe, M.D., of the National Databank for Rheumatic Disease (NDBRD) in Wichita, Kan., at the American College of Rheumatology meeting.

The FDA, prompted by reports of an increased risk of lymphoma seen in some clinical trials of the medications, added a warning on the labels of Remicade (inflixumab), Enbrel (etanercept), and Humira (adalimumab).

"In contradistinction," Dr. Wolfe said, "we found no overall increase in the rate of cancer associated with biologic therapies."

Skin cancer was an exception, with melanoma and non-melanoma skin cancers both slightly increased among users of biologic therapies, Dr. Wolfe said.

The findings come from an analysis of 13,000 participants in the rheumatic disease database between 1998 and 2005, who reported all medication use as well as all cancers semi-annually.

The rates seen in those with rheumatic disease were compared to those seen in the general population and reported to National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) database, Dr. Wolfe reported.

The comparison found:

• Nearly half of the rheumatoid disease patients (48%) used one of the biologic therapies.
• Over the study period, there were 623 incident cases of non-melanoma skin cancer and 537 other cancers, including 32 cases of melanoma.
• The standardized incidence rate for all cancers was 1.0, with a 95% confidence interval from 0.9 to 1.0.

There was a slightly increase risk of non-melanoma skin cancer. The odds ratio was 1.5, with a 95% confidence interval from 1.2 to 1.8, which was statistically significant at P<0.001.

The risk of melanoma showed the highest rise (with an odds ratio of 2.3) but the increase was not statistically significant (P=0.07), Dr. Wolfe said.

There were no other statistically significant increases in risk, he said.

"The data from the clinical trials do not provide adequate guidance for the safety of these drugs," he said.

The link had been biologically plausible, he said, because the therapies alter the function of the immune system, and changes in the immune system are known to render a person more vulnerable to a malignancy.

Cancer is a "significant concern because patients today are very well-informed," commented John Cush, M.D., of Presbyterian Hospital of Dallas, who was not part of the study. The issue has to be put in perspective by physicians, he said.

"I think this is reassurance" both for patients and for doctors who may not have extensive experience with the biologic medications, Dr. Cush said.

Some of the odds ratios for cancer are high -- notably those for skin cancer -- but "the risk to any one individual is still very low," he said.

Dr. Wolfe said he has had research support from several pharmaceutical companies, including Amgen, Aventis, Bristol-Myers-Squibb, and Centocor.