New Treatment for Gout

Sept. 4, 2008 -- A study by researchers at Duke University Medical Center shows that a new drug designed to regulate levels of uric acid in people with difficult-to-treat gout may help them cope with the painful condition.

About 5 million people in the U.S. suffer from gout. The disease develops from an excess of uric acid in the blood. This buildup may be because of increased production of uric acid or problems in ridding it from the body. Excess uric acid may deposit crystals in joints -- usually the big toe, foot, ankle, or knee -- causing a painful inflammation.

Maintenance treatment often includes use of drugs such as allopurinol and probenecid, which reduce blood levels of uric acid. However, some patients cannot tolerate medications or are not helped by drugs. Researchers developed a drug called pegloticase, which converts uric acid into a chemical compound that is more soluble in blood and easier to excrete.

"The generally accepted goal of therapy is to reduce serum urate concentrations to less than 6 milligrams per deciliter, and we found that pegloticase can do that very, very quickly," says John Sundy, MD, a rheumatologist at Duke and the lead author of the study. "Perhaps what is most important is that it did this in patients who had run out of therapeutic options."

Sundy, along with his colleagues in other medical centers and at Savient Pharmaceuticals, the company that is developing pegloticase, studied the use of the drug in 41 patients who were randomly assigned to one of four treatment groups. Participants received either 4 or 8 milligrams of the injectable drug every two weeks, or 8 or 12 milligrams every four weeks, for a 12- or 14-week period.

The results of the phase II trial showed that pegloticase regulated patients' uric acid levels within six hours on average, and those levels were maintained throughout the study in the two groups at the higher dosage levels. The most effective dose was found to be 8 milligrams every two weeks. During the treatment, 88% of the patients experienced gout flares. The most common adverse events included kidney stones, joint pain, anemia, headache, muscle spasms, nausea, and fever. Most were deemed "mild or moderate in severity," according to the researchers.

The results of the phase three trial of pegloticase will be presented at the annual meeting of the American College of Rheumatology in October 2008. A patent is pending on the drug.