ACR: Humira Does Not Affect Flu Vaccination Efficacy

WASHINGTON, Nov. 16 -- Vaccination against influenza or pneumococcal disease is safe and effective in patients with rheumatoid arthritis who are taking Humira (adalimumab), a researcher said here.

The finding, which emerged from a large randomized placebo-controlled study, should provide reassurance for both patients and their doctors that the vaccinations remain a valuable tool against infection, said Alan Kivitz, M.D., of the Altoona Center for Clinical Research in Duncansville, Pa., at the American College of Rheumatology meeting here.

There had been some concern about the efficacy of the vaccines inferred from clinical trial data of Humira, which suggested a higher rate in infections, said Dr. Kivitz.

Some patients and physicians had worried that the TNF-alpha inhibitors might interfere with the immune response, rendering a vaccination useless and possibly even dangerous, he said. "I had a patient just last week who wanted to receive a flu shot and wondered if it was safe and effective," Dr. Kivitz said.

At least in the case of Humira, he said, those worries can be laid to rest. Both for pneumococcal disease and influenza, vaccines produced protective immune responses in patients taking the drug and those taking placebo at roughly the same levels, Dr. Kivitz reported.

He said other, smaller trials have shown similar results for other biologic therapies.

Dr. Kivitz and colleagues enrolled 226 volunteers with rheumatoid arthritis who had not been taking any biologic therapy for at least two months, although they were allowed to be taking methotrexate or prednisone.

They were randomized to either Humira or placebo, during the 2004-2004 flu season, and those in the active arm were given an initial dose of 80 mg of the drug, followed by 40-mg injections at two-week intervals.

At day eight of the 36-day study, the researchers took baseline antibody titers and vaccinated the volunteers against either the flu or pneumococcal disease.

Some volunteers already had protective antibody levels, the study found, but:

• Among those who were vulnerable to pneumococcal disease, 57% of the placebo group and 67% of the Humira group had a protective response at day 36. The difference was not statistically significant.
• Among those who were vulnerable to the flu, 87% of the placebo group and 97.6% of the Humira group had a protective response at day 36. The difference was not statistically significant.

The bottom line, Dr. Kivitz said, is that "our RA patients can be safely and effectively vaccinated."

He said the finding will probably not change clinical practice, because most rheumatologists are already recommending vaccination. "I think this gives us reassurance that for adalimumab patients with RA, we now have confirmation that we are inducing an appropriate immune response," Dr. Kivitz said.

"Hopefully this type of study will remind doctors (to offer vaccination) and also let patients know that it's safe and they're not going to get worse," commented John Cush, M.D., of Presbyterian Hospital of Dallas, who was not part of the study.

"If the average person gets the flu, he's down for five days, feels lousy, misses work," Dr. Cush said. In rheumatoid arthritis patients, "it's not unreasonable to expect a more serious disease course, including hospitalization and even death."

The great part of Dr. Kivitz's study, he said, is that it tells both doctors and patients that the vaccinations produce an immune response without adverse effects.

One of the authors reported receiving consulting fees from Abbott and another one of the authors is an employee at Abbott.