Gout is a painful condition that is caused by an excess of uric acid in the blood. This excess may be deposited in joints resulting in pain and inflammation. The joints most often affected are in the big toe and other parts of the foot, as well as the ankle and knee.
Treatment often includes drugs such as probenecid and allopurinol. However, some patients do not get relief with these drugs or are unable to tolerate them.
Researchers at Duke University Medical Center and Savient Pharmaceuticals have recently conducted a phase II trial of a drug called pegloticase which shows great promise in reducing the level of uric acid in the blood to targets levels within a few hours. Pegloticase works by converting the uric acid into a substance that the body can more easily excrete.
The study included 41 patients who were randomly assigned to one of four different treatments – 4 or 8 mg injectible medication every 2 weeks, or 8 or 12 mg every 4 weeks – for a 12 or 14 week period. The treatment was given as an infusion which required about 2 hours.
Most of the patient’s uric acid levels reached “normal” levels within six hours, regardless of which dosage or frequency they received. In addition, those levels were sustained for the entire treatment period in those groups receiving the higher dosages. The most effective dose was found to be 8 mg every 2 weeks.
“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.
“We were delighted to see this response, because all of the patients in our trial had already tried all the existing treatments for , and nothing was helping them,” said Sundy, who added that more studies need to be conducted to confirm and expand the findings.
During the treatment period, 88% of the patients did experience flares. Some of the patients also experienced mild to moderate side effects, including joint pain, anemia, muscle spasms, nausea, headache, kidney stones and fever.
The study findings were published online and in the September issue of the journal Arthritis & Rheumatism. Results from a phase III study are expected to be presented in October at the annual meeting of the American College of Rheumatology, in San Francisco.