Keryx shares more than doubles on kidney drug data

NEW YORK (AP) -- Shares of Keryx Biopharmaceuticals Inc. more than doubled in value this week even after a steep drop Friday as Wall Street responded enthusiastically to clinical trial data for Zerenex, an experimental treatment for a side effect of kidney disease.

Keryx said Monday that Zerenex, which is designed to treat elevated serum phosphate levels in patients with end-stage kidney disease, worked much better than a placebo in a late-stage study. The drug was better than a placebo at reducing serum phosphorus levels and improving iron levels, and patients treated with the drug did not need as much iron or other treatments for anemia.

The New York company has no approved drugs, and its shares surged 82 percent Monday. The stock kept rising even after Keryx said it would sell more stock, a move that often causes share prices to decline. The company is selling $55 million in stock to fund prelaunch activities for the drug.

On Thursday Keryx shares peaked at $9.98, their highest price in more than five years. The stock fell more than 20 percent Friday to close at $7.11, but that was still more than double its closing price from a week ago and almost triple its price at the end of 2012.

The shares fell more than 65 percent in April after the company said its colorectal cancer drug capecitabine failed in a late-stage study.

Keryx plans to file for marketing approval of Zerenex in the U.S. and Europe during the second quarter.