"Substantial" toxicity seen with PegIntron use

WASHINGTON (Reuters) - Schering-Plough Corp's injectable drug PegIntron carries "substantial toxicity" and had no effect on overall survival in melanoma skin cancer patients undergoing surgery, U.S. Food and Drug Administration staff reviewers said in documents released on Thursday.

Schering is seeking FDA approval to sell its drug, PegIntron, for use with surgery in cases where the melanoma has spread to the lymph nodes and surgery is needed to remove both the cancer and the surrounding lymph nodes.

PegIntron, also known as peginterferon, is already approved for liver disease. It is also approved for use in conjunction with the company's Rebetol for chronic hepatitis C patients with liver disease.

The FDA released the documents ahead of an advisory committee meeting on Monday to discuss whether to approve new uses for the drug. The agency usually takes the advice of its outside experts but not always.

PegIntron is a type of alpha interferon protein-based drug that aims to boost the body's immunity and help cells function normally.

In a separate document, Schering said the drug increased the time before the cancer reoccurred, with patients who were only observed experiencing a relapse a median of 25.5 months compared with 34.8 months with PegIntron.

The only other approved drug for use after surgery for melanoma is Schering's Intron A, which has the same active ingredient as PegIntron and has been shown to prevent relapse but does not give patients a survival advantage, the company said.

Intron A also requires the drug be given intravenously five times a week for four weeks, whereas PegIntron can be given by the patient at home once a week, Schering said.

FDA staff agreed that there was "highly significant" increase in the length of time before relapse with PegIntron just as with Intron-A.

"However, there was no effect on overall survival observed and substantial toxicity occurred with treatment regimen administered in this study," they concluded.

Shares of Schering were down less than 1 percent at $28.05 in morning trading on the New York Stock Exchange.

The FDA posted the staff memo and the Schering document on its website here

(Reporting by Susan Heavey and Julie Vorman; Editing by Derek Caney, Dave Zimmerman)