Gout Drugs in the Pipeline
Four decades have passed since a new gout drug has become available for people who experience the agonizing pain of needlelike uric acid crystals piercing their joint tissues. That doesn’t mean that researchers haven’t been working to develop one, or to investigate gout further. Studies are under way:
• Febuxostat. Like allopurinol, this drug blocks the enzyme xanthine oxidase, which breaks down purines and converts them into uric acid. Blocking xanthine oxidase decreases the formation of uric acid. One of the most recent febuxostat studies shows a 62 percent reduction in uric acid level in 760 people who had gout for one year. Febuxostat may be up for FDA approval in late 2008 or early 2009.
• Oxypurinol (Oxyprim). A xanthine oxidase inhibitor, study results show that oxypurinol is an option for people whose gout is so severe that kidney function has declined. When kidney function is impaired, allopurinol can become toxic, so high doses of it are no longer an option for reducing the uric acid level. Oxypurinol helps reduce uric acid, while preventing the toxic effects of allopurinol.
• Pegloticase (Puricase). Most animals produce the enzyme uricase, which makes uric acid soluble. Through evolution, however, humans and other primates lost the ability to produce it, meaning uric acid levels can increase and crystallize. Pegloticase, a form of the uricase enzyme made from mammals, puts the missing enzyme back into humans. Results of a new phase III study – the last phase of testing before FDA approval is sought – show that infusions of pegloticase every two or four weeks not only reduced uric acid level and gout symptoms, but also dissolved tophi and improved the quality of life.
• Rilonacept. In an attempt to decrease the swelling and symptoms caused by gout, rilonacept targets interleukin-1, a protein that sparks inflammation. This experimental injectable drug would provide a way to treat people with gout who are unable to take colchicine, corticosteroids or nonsteroidal anti-inflammatory drugs to reduce inflammation. In a small study, 60 percent of people injected with rilonacept had a 75 percent improvement in pain, and a measure of inflammation dropped 59 percent.
