(Adds details from conference call, analyst comments, background; updates share movement)
By Vrinda Manocha
Nov 5 (Reuters) - Keryx Biopharmaceuticals Inc's kidney drug proved effective in treating chronic kidney disease patients not on dialysis, sending the company's shares to a seven-year high on hopes the drug could achieve blockbuster status.
Keryx shares rose as much as 27 percent to $14.07 on Tuesday morning on the Nasdaq.
Chief Executive Ron Bentsur said the drug, Zerenex, could exceed $1 billion in sales, even if it penetrated only 7 percent of the market for chronic kidney disease patients not on dialysis.
Analysts said this market could be larger than that for end-stage renal disease patients on dialysis, another condition for which Zerenex has been tested.
"This is great news that opens up the pre-dialysis market for the company," Maxim Group analyst Jason Kolbert told Reuters.
Sanofi SA, which markets two similar drugs that will lose patent protection next year, could partner with Keryx to develop or market Zerenex, Kolbert said.
Sanofi's Renvela and Renagel are considered standard treatments to reduce phosphorus levels in kidney disease patients on dialysis.
"A wide range of companies from Big Pharma to biotech ... companies like Johnson & Johnson and Amgen could (also) partner with Keryx," Kolbert said.
Keryx said on Tuesday that Zerenex met the main goals of a mid-stage trial in patients with chronic kidney disease who had iron deficiency anemia and elevated levels of serum phosphorus.
The drug showed a statistically significant reduction in serum phosphorus, high levels of which are associated with progression of the disease and increased rate of death, after 12 weeks of treatment compared with a placebo.
Zerenex also increased the percentage of iron available in the body to make red blood cells, Keryx said.
"The results show for the first time, a significant benefit in both decreasing phosphate levels and a benefit in iron storage parameters and hemoglobin," H.C. Wainwright & Co analyst Reni Benjamin said.
Zerenex will reduce the need for chronic kidney disease patients to take intravenous (IV) iron and erythropoiesis-stimulating agents (ESAs) to boost red blood cell production. ESAs are expensive and carry the risk of causing blood clots, heart attacks and strokes.
"The only real competition for pre-dialysis patients are IV iron and ESAs, but those are not well used and represent a sort of last option for patients," Benjamin said.
"Oral pills are more convenient to administer and may better regulate iron store in the body."
Zerenex is safe and well-tolerated, Keryx said. Serious adverse events occurred in six patients taking the drug compared with 10 taking the placebo.
The company said in January that Zerenex met the main goal of a late-stage study, reducing phosphate levels in the blood of patients with end-stage renal disease on dialysis.
The U.S. health regulator is expected to review the drug to treat that condition on June 7 next year.
Keryx shares were up 20.5 percent at $13.38 on the Nasdaq. (Editing by Kirti Pandey)