Krystexxa is manufactured by Savient Pharmaceuticals of New Jersey.

Krsytexxa’s new drug application has been under review since December. The FDA already has delayed a decision on the drug once.

Krystexxa is an injectable enzyme designed to lower the body's uric acid levels when administered either once or twice a month. Gout is a condition caused by a buildup of uric acid in the body. The drug appears to reduce gout’s symptoms such as relieving swollen joints and pain flare up. Gout affects about 8 million Americans and is most common in men over 40.

In a clinical study, about 24 percent of patients taking Krystexxa suffered a serious side effect, compared with 12 percent of patients taking a placebo pill. There were six deaths among patients taking the drug compared with three among patients taking placebo, though FDA noted many of them had pre-existing heart conditions.

"Because most of the patients developing the serious cardiovascular adverse events had other cardiovascular risk factors... there was uncertainty concerning whether the cardiovascular adverse events represent a genuine safety signal," states Dr. Bob Rappaport, FDA's director for rheumatology products, in a review posted to the agency's Web site.

The FDA is scheduled to ask a panel of outside arthritis experts next Tuesday to weigh in on the drugs risks and benefits. Though not required not required to follow the group's advice, the FDA generally adopts their recommendations. A final decision on Savient's drug is expected by the end of July.

It is possible that the FDA will consider whether additional studies are needed to evaluate Krystexxa's impact on the heart.

An analyst said the drug can likely win approval so long as the company agrees to limit its use to the target patient population and closely monitor negative side effects. The company is specifically seeking an indication for gout patients who are not receiving relief from other treatments.

For more information: http://www.fda.gov/AdvisoryCommittees/Calendar/ucm155149.htm

Labels: death, drug application, enzyme, FDA, Gout, Krystexxa, savient, uric acid