(Reuters) - Keryx Biopharmaceuticals Inc said a late-stage trial of its experimental drug for kidney disease met the main study goal of reducing phosphate levels in blood, sending the company's shares up as much as 49 percent.
The level of phosphate in blood increases when kidney function declines. Keryx is testing Zerenex as a treatment for elevated serum phosphorus levels, or hyperphosphatemia, in patients with end-stage renal disease on dialysis.
The drug showed a statistically significant reduction in patients' blood phosphate level compared with a placebo over a four-week period.
Zerenex also met the two secondary goals of increasing the levels of two proteins in the blood and reducing the need for intravenous iron and erythropoiesis-stimulating agent (ESA), an agent used to stimulate red blood cell production. Declining kidney function often leads to anemia.
"The trial has demonstrated profound benefits not just in the primary endpoints but also in the secondary endpoints. As such, we think the risks of this drug, one - being approved, and two - being a commercial success, go down dramatically," Maxim Group analyst Jason Kolbert said.
The company expects to file for regulatory approvals of the drug in the United States and Europe in the second quarter of 2013.
Zerenex, the company's only clinical candidate, is also being tested in a mid-stage study in patients with chronic kidney disease who are not dependent on dialysis.
If approved, Zerenex will compete with Renagel and Renvela, both developed by Sanofi's biotech subsidiary, Genzyme Corp.
Shire Plc's Fosrenol and Fresenius Medical Care's PhosLo also claim market share for the same indication.
These drugs are called phosphate binders as they attach themselves to phosphate in the gastrointestinal tract and prevent its absorption in the body.
"In our view, the differentiated profile of Zerenex represented by these results, positions it, if approved, to potentially overtake Renvela as the market leader in the phosphate binder market over time," MLV & Co Investment Research analyst Ed Arce said in a note.
Maxim Group's Kolbert said even in the face of current standards of care, with drugs like PhosLo or Renvela going generic, there will be substantial health and pharmaco-economic advantages associated with Zerenex.
"We have said all along that Zerenex is the only phosphate binder that has the potential to transcend into another dialysis category, in this case anemia management, and generate a benefit," Keryx CEO Ron Bentsur said on a conference call.
Shares of New York City-based Keryx were up about 40 percent at $4.80 early on Monday on the Nasdaq.
(Reporting by Esha Dey and Pallavi Ail in Bangalore; Editing by Roshni Menon and Sreejiraj Eluvangal)