A new approach to preventing gout attacks looks promising for people not already helped by existing treatments.
Researchers are looking at an anti-inflammatory drug called canakinumab (Ilaris) to treat this painful form of arthritis.
Very large effect
Instead of targeting excessively high uric acid levels as existing gout drugs do, the new strategy aims to reduce overall inflammation. The drug goes after a specific inflammatory molecule called interleukin-1.
The result was a 50% drop in gout attack risk, the researchers found.
"This was a very large effect," said study lead author Dr Daniel Solomon, a rheumatologist with Brigham and Women's Hospital in Boston.
He acknowledged it was "very surprising" that the drug packed an equally protective punch whether patients had normal uric acid levels or very high levels.
But Ilaris is unlikely to be the preventive drug of choice any time soon, said Solomon.
For one, it has not yet received approval for gout treatment in the United States. And most patients already achieve risk reduction with standard uric acid-lowering treatments, such as allopurinol (brand names Zyloprim, Aloprim).
What's more, decades-old allopurinol is a cheap daily pill.
"Canakinumab is very expensive," said Solomon. Its main role to date is as a last-ditch treatment for rare, so-called "orphan" diseases. At its current price, he said, "it is not a viable option for most patients with gout".
Also, it must be injected every three months by a caregiver.
Still, Solomon said Ilaris may have a clinical role for patients who don't respond to or tolerate standard medications.
Prior research had shown that interleukin-1B inhibitors can shorten gout attacks, but it wasn't known if they could prevent them, the study authors said.
The new research was funded by Novartis, the maker of Ilaris. The results were published online in Annals of Internal Medicine.
Gout is the most common form of inflammatory arthritis. When a chemical called uric acid builds up in the body, it triggers the formation of tiny jagged crystals that cause severe joint paint, most often in the foot, particularly the big toe. Gout's prevalence has increased considerably in recent decades.
Heart disease and gout often overlap, the researchers noted. To explore whether Ilaris has potential as a preventive measure, investigators conducted a secondary analysis of the so-called Canakinumab Anti-Inflammatory Thrombosis Outcomes Study (CANTOS). This enlisted more than 10 000 heart attack patients to see if Ilaris might help reduce future cardiovascular complications among high-risk individuals.
The researchers found that patients treated with four injections of Ilaris a year faced half the risk for a gout attack, compared with those given a dummy (placebo) treatment, regardless of uric acid levels.
"We have no strong reason to believe that [Ilaris] would be less effective in patients without known heart disease," said Solomon.
Howard Feinberg, a professor of rheumatology at Touro University in Vallejo, California, agreed.
Based on the current and prior research, "we can assume that this drug will work for most patients", including those without a history of heart disease, he said.
Feinberg said he "would not recommend its use for someone who did well on older medications" because of its high cost and the need to give it as in injection.
"The type of patient who would benefit the most is someone who was allergic or could not take standard therapy," Feinberg said, mentioning patients with kidney disease. "This treatment is also ideal for someone whose gout could not be controlled on allopurinol or other older therapies."
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