Bristol-Myers Squibb, the American drugs group caught up in a patent dispute over a generic version of the Plavix blood-thinner, has ousted Peter Dolan, its chief executive for five years, after pressure from a US Government monitor.

Bristol-Myers which distributes the blockbuster drug in America for its European partner Sanofi-Aventis, also said Richard Willward, its general counsel had left the company.

Both departures are effective immediately and Bristol-Myers named director James Cornelius as an interim replacement for Mr Dolan until a permanent replacement is found.

Mr Willward will be replaced temporarily by Sandra Leung, vice-president and corporate secretary.

The dramatic moves follow a board meeting yesterday during which Frederick Lacey, a former federal judge who has been monitoring developments in a high-profile patent dispute with Apotex of Canada, urged Bristol-Myers to terminate the contracts of Messrs Dolan and Willward.

Judge Lacey has been presiding over a probe into a "deferred prosecution agreement" struck between Bristol-Myers, Sanofi-Aventis and Apotex over its cheap generic version of Plavix.

Mr Dolan has faced criticism for agreeing to a deal that would have seen Bristol-Myers and Sanofi-Aventis pay Apotex as much as $40 million to delay selling its version of Plavix until 2011. Last year, Plavix generated $3.8 billion of sales.

But last month, after the agreement was rejected as being anti-competitive by American authorities, Apotex launched its generic version anyway and flooded the market with an estimated $1 billion of sales within three weeks.

Both Sanofi-Aventis and Bristol-Myers succeeded in securing an injunction preventing further sales of the generic, but no product recall was ordered and third-party sales were permitted.

The success of Apotex's drug prompted Sanofi-Aventis to issue a profits warning and substantially downgrade its profits forecasts for the year. Bristol-Myers has also cut its full-year earnings forecasts.

Bristol-Myers stressed today that both Judge Lacey and the US Attorney found that no violation of the deferred agreement had taken place. It also said neither the company nor any of its employees had been found to have acted illegally.

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