* Drug under review for treating allergy-related eye itch
* Advisory panel meets Friday to evaluate data
* Ista shares gain more than 5 pct (Adds analyst comments, updates share movement)
By Lisa Richwine
WASHINGTON, June 24 (Reuters) - No serious safety problems were reported in studies of Ista Pharmaceuticals Inc's ISTA.O proposed eye drops for allergy-related itching, U.S. drug reviewers said in documents released on Wednesday.
In one study that evaluated risks, 25 percent of patients treated with the drug reported a change in taste, such as a bitter taste or aftertaste, said staff in the Food and Drug Administration division that reviews eye drugs.
The analysis was prepared for an advisory panel that meets Friday to consider if adequate safety and effectiveness has been shown for the drug, called Bepreve.
Shares of Ista gained 5.5 percent in afternoon trading to $3.99 on the Nasdaq.
Several medicines are approved for treating allergies, but Ista said there was a need for new options with fewer side effects. Approved drugs may cause sleepiness, dry mouth and other problems.
Bepreve reduced eye itching "with few mild and transient" side effects, the company said in a separate summary released by the FDA.
SunTrust Robinson Humphrey analyst Frank Pinkerton has forecast Bepreve sales of $12 million in 2010 if the drug wins approval for U.S. sales.
The advisory panel, a group of outside experts, will discuss whether adequate evidence of safety and effectiveness was provided for Bepreve as well as for another drug, River Plate Biotechnology's proposed solution to treat dry eye.
FDA reviewers, in a separate analysis prepared for the meeting, said they had identified "three major statistical issues" in River Plate's application to market a hyaluronate sodium solution under the name Rejena.
One of the company's key studies lacked a "robust treatment effect" for the product, the reviewers said. An earlier study failed to meet its main goal to show effectiveness and an FDA reviewer could not replicate the company's finding that secondary goals were met, the FDA staff said.
Alcon Inc ACL.N holds U.S. marketing rights for the River Plate drug. The product already is sold in Europe.
In a separate summary, River Plate said there was "compelling and scientifically thorough evidence" of effectiveness, safety was "widely established" and the drug's "benefit-to-risk evaluation is overwhelmingly positive."
UBS analyst Marc Goodman, in a research note, said there was a "strong likelihood" the FDA panel would recommend against approval of the River Plate drug and might urge additional studies. Goodman said he had no sales forecast for the drug and maintained a "strong positive view" of Alcon overall.
The FDA will consider the advisory panel's input before deciding whether to approve the drugs. The agency usually follows panel recommendations.
Alcon shares were up 0.2 percent at $113.68 on the New York Stock Exchange on Wednesday afternoon.
The FDA posted the meeting documents here. (Reporting by Lisa Richwine; Editing by Lisa Von Ahn, Gerald E. McCormick and Matthew Lewis)