Pfizer Inc. is in talks to buy Wyeth in a deal potentially worth more than $60 billion, the Wall Street Journal reported Friday quoting people familiar with the matter.

The anonymous source said the two companies have held discussions for several months but the deal wasn't imminent, and warned that the talks are specially fragile and could collapse due to the volatility in the market and the uncertainty in the economy, the newspaper reported.

Shares in Wyeth rose 13.5 percent in Frankfurt's trading on Friday after the report. The increase was the highest since August 2007 , according to Reuters.

European pharmaceutical stocks also benefited early Friday from the news.

The companies have not confirmed the report.

Pfizer