The FDA approves new drug for gout

The Food and Drug Administration said Tuesday that it has approved a new drug to treat gout in patients who do not respond to existing therapy. The drug is called Krystexxa and is manufactured by Savient Pharmaceuticals Inc. of East Brunswick, N.J. The FDA had rejected the drug in August of 2009 because of manufacturing problems.

In a letter to the company then, the agency said that the potential commercial supplies of the drug were not identical to the product used in clinical trials.

Gout occurs because of an excess of the metabolic waste product uric acid, which precipitates out of the bloodstream and into joints and soft tissue as needle-like crystals that can be very painful. They also cause intermittent swelling, redness, heat, pain and stiffness in the joints. Although most people tend to associate the disorder with rich foods, it is more commonly linked to obesity, high blood pressure, high cholesterol and diabetes. It is most common in men, post-menopausal women and people with kidney disease.

The conventional treatments include the drugs allopurinol and febuxostat, both of which inhibit the enzyme xanthine oxidase, which produces uric acid from DNA in food. Krystexxa, known generically as pegloticase, is an enzyme that acts directly on uric acid, converting it into harmless chemicals that are excreted in the urine. The drug is given by an intravenous infusion every two weeks.

"About 3% of the 3 million [American] adults who suffer from gout are not helped by conventional therapy," Dr. Badrul Chowdhury, director of the FDA's division of pulmonary, allergy and rheumatology products, said in a statement. "This drug offers an important new option for them."

But the agency cautioned that about 1 in every 4 patients receiving an infusion of the drug suffers a severe allergic reaction and urged physicians to give patients a corticosteroid and an antihistamine before infusing the drug.