Given by injection just underneath the skin, rilonacept (IL-1 Trap) blocks interleukin-1, a protein involved in inflammation. A new study of 10 people with severe gout shows that it substantially decreases both disease activity and pain.
The findings were presented at the American College of Rheumatology's Annual Scientific Meeting in Boston.
"Lots of gout patients can't take standard anti-inflammatory drugs such as nonsteroidal anti-inflammatory drugs (NSAIDs), colchicine, or systemic steroids because they may have kidney problems, heart problems, or diabetes," explains researcher Robert Terkeltaub, MD.
Terkeltaub is section chief of rheumatology-allergy at the VA Medical Center in San Diego and a professor of medicine at the University of California, San Diego. "Now we can help break the inflammatory loop in these patients," he says.
"IL-1 is a lynch pin of gout inflammation, and if we can block the lynch pin, we can stop the inflammatory cascade," Terkeltaub tells WebMD.
Gout is a condition characterized by "flares" of intense pain, redness, inflammation, and warmth in the affected joint. It is caused by an accumulation of uric acid crystals in joints, which can also build up in other areas of the body. As the disease progresses, these flares may become more frequent and patients may develop joint deformity and large deposits of crystals, which can become visible under the skin (called tophi). Patients with gout can also develop kidney stones and kidney damage.
Uric acid is found naturally in the body. In gout, there is generally a problem with either too much production of uric acid or problems in getting rid of the uric acid, or both. During an attack, gout is typically treated with drugs that cool inflammation. In addition, uric-acid-lowering drugs are sometimes prescribed.
Some uric-acid-lowering drugs actually cause flares, and it is possible the new drug may be used along with drugs to lower uric acid to help prevent such flares.
In the new study of 10 people (average age 62) with severe, chronic gout, participants received two weekly injections of a dummy drug followed by six weekly injections of rilonacept. In the second through eighth week of the study, 70% of participants had at least a 50% improvement in their pain; 60% of participants had at least a 75% improvement in their pain. By contrast, none of the participants showed improvement while they were receiving the dummy injections.
Levels of C-reactive protein in the blood, a marker of inflammation, decreased about 59% by the end of rilonacept therapy. Mild to moderate reactions at the drug injection sites were reported, but there were no deaths or serious adverse effects reported from this study.
"It's really gratifying to see patients that are considered the worst of the worst respond," Terkeltaub says. "If it works in the worst of the worst, we are hopeful it will work in the less than worst of the worst."
Michael Hershfield, MD, a professor of medicine and biochemistry at Duke University School of Medicine in Durham, N.C., tells WebMD that "a drug like this or any other that blocks IL-1 could prevent flares that occur when we are having a dramatic effect in lowering uric acid levels. The two could work very well together." Hershfield developed a new uric-acid-lowering drug called pEG-Uricase, which is now in clinical trials.
All in all, the new drug "looks very promising," he says. "There is a lot more recognition of the problem of severe refractory gout and a lot of people working on different approaches at the anti-inflammatory and the uric-acid-lowering level," he says.