Elan Pharmaceuticals chief financial officer Shane Cooke has exercised his options over 413,000 shares in the biotech group.

Mr Cooke paid $2.11 a share for 400,000 of the shares and $2.79 a share for the balance, a total outlay of $880,270. He subsequently sold 163,000 shares back into the market at a price of $8,1768 a share, or $1.33 million, yielding him a profit of more than $450,000 on the transaction.

Mr Cooke has been chief financial officer at Elan since 2001. He was made an executive director last May.

Following the transaction notified to the Irish Stock Exchange yesterday, Mr Cooke continues to hold 250,000 shares in the company, worth just over $2 million at last night's close. According to the statement to the Irish Stock Exchange, Mr Cooke holds no other options over Elan stock following this week's dealings.

People close to the company stressed that Mr Cooke's decision to sell some of the shares acquired under the options should not be read in a negative light.

Market sources said the decision to sell a portion of the shares was probably related to tax liabilities arising from the exercise of the options.

The dealings on the New York Stock Exchange came a day after the company notified the Securities and Exchange Commission that chief executive Kelly Martin had negotiated an enhanced severance deal with Elan in the event of losing his job as part of any change in control at the company.

Elan is currently looking to win approval from the US regulator to resume sales of its key multiple sclerosis drug Tysabri, which was withdrawn in February after two trials patients fell seriously ill, one fatally.