UPDATE 2-Savient gout drug gets mixed marks, shares jump

* FDA says drug appears effective, but cites safety issues

* Savient shares jump 48 percent

* FDA to seek advice from panel of advisers Tuesday (Adds analyst comments, shares)

By Susan Heavey

WASHINGTON, June 12 (Reuters) - The U.S. Food and Drug Administration said on Friday Savient Pharmaceuticals Inc's (SVNT.O) proposed gout drug Krystexxa appears effective, lifting its shares 48 percent despite serious serious health issues cited by the agency.

The FDA's review of two company studies raised several concerns, including one about a greater number of patients taking Krystexxa who suddenly died or had heart failure, Dr. Bob Rappaport, head of the FDA division that handles such rheumatology drugs, wrote in a memo released on Friday.

But the agency "does not dispute the efficacy" of Krystexxa at the currently proposed dose regimens of every two or four weeks, Rappaport said in the memo, which was released ahead of a public meeting on Tuesday to discuss whether to recommend approval of the drug.

Savient is seeking U.S. approval for the drug to treat patients whom other therapies have not helped.

At the meeting, agency officials will ask the panel whether Savient has enough data to determine if the benefits of the drug outweigh its risks. The FDA usually, but not always, follows its panel recommendations.

Leerink Swann analyst Joseph Schwartz interpreted the FDA comments as favorable on both the effectiveness and safety of Krystexxa.

He said the FDA division of cardiovascular and renal drug products "concluded that the distribution of cardiovascular deaths and serious adverse events was not obviously unusual in view of the fact that they occurred in patients predisposed to such events."

Savient, in a separate document also released on Friday, said the drug was important for patients who have no other options and that it "can be successfully managed with careful clinical monitoring."

The agency posted the memo to its website here

Shares of Savient were up $2.87 at $8.80 in morning trading on the Nasdaq. (Additional reporting by Ransdell Pierson; Editing by Steve Orlofsky)