Biologics battle joint, skin diseases

March 1, 2006

In patients for whom rheumatologists once hoped to achieve 20 percent improvement, Dr. Lisse says that with TNF inhibitors, "We're now looking for 50 or 70 percent, or even remission."

Tucson, Ariz. - As in psoriasis and other dermatologic diseases, biologic drugs represent a powerful weapon against autoimmune illnesses that attack the joints and sometimes the skin, a leading rheumatologist tells Dermatology Times.

He says that, in a nutshell, "TNF is actually a mediator that, in response to an inflammatory stimulus, turns on the immune system."

"TNF has been found in abundance in the synovial lining of peripheral joints in patients with rheumatoid arthritis (RA), and the synovial lining in the spinal joints of patients with ankylosing spondylitis (AS)," he explains.

In light of this, he says that although TNF inhibitors were originally developed for another purpose, they've been very effective in treating these diseases. "Psoriatic arthritis may feature either peripheral or spinal inflammation," he adds.

In patients for whom rheumatologists once hoped to achieve 20 percent improvement, Dr. Lisse says that with TNF inhibitors, "We're now looking for 50 or 70 percent, or even remission."

And putting patients into remission saves money on disability and other long-term costs of chronic autoimmune diseases, he adds. As such, Dr. Lisse says, "It's been a very exciting time for us with these products, because we can do a lot more for our patients than we ever could in the past."

At the same time, TNF inhibitors' success has raised the bar on patient expectations, Dr. Lisse concedes.

"The downside of the medications include the fact that they are parenteral," he adds, with Enbrel (Amgen) being injected subcutaneously either once or twice weekly, Humira (Abbott) every week or two.

Conversely, he says, rheumatologists administer Remicade (Centocor) intravenously at a starting dose, then loading doses two and four weeks subsequently, followed by every eight weeks thereafter.

Dr. Lisse says that because TNF is an inflammatory mediator and may play a key role in immune response to infection, rheumatologists are always on guard against infections in patients using TNF inhibitors. Additionally, the expense of these drugs, which he says can easily cost at least $16,000 per patient per year, dictates that very few patients can pay for them out of pocket.

"That's just a starting dose," he adds. "With Remicade and Humira, one can end up increasing the dose and cost" over time.

Since etanercept, adalimumab and infliximab have earned Food and Drug Administration (FDA) approval for treating PsA, he says, "It's clear that they benefit the joints. And for rheumatologists, there's the advantage that they also benefit the skin."

The medications having earned approval for PsA, moreover, makes it easier for rheumatologists to get TNF inhibitors approved by insurance plans, he adds.

TNF inhibitors have a different safety profile compared to conventional alternatives, Dr. Lisse says.

"One needn't worry about liver problems or blood counts as much as we do with some of the (oral) medications we're using," he explains.

Moreover, Dr. Lisse says it appears that methotrexate may not improve treatment efficacy when added to biologic drugs.